Tales From the Dark Side: Putting Car Tires on Motorcycles

Tales from the Dark Side

From the Dark World of Nonconformity They Emerged…On Car Tires.

Have you ever found yourself unwittingly in the middle of a heated religious or political debate between two vehemently opposed participants? Not since the dispute over conventional oil vs. synthetic oil have I seen such polarized and passionate opinions in the motorcycle world. The question is, unlike the face off over the slippery stuff, could this practice by those known as “Dark Siders” actually be a dangerous one?

“I’m interested in signing up for one of your Stayin’ Safe training tours,” the email began. “But before I register, I want to make sure it’s OK to participate if I have a car tire mounted on my Gold Wing.” A what? Did he say a “car tire?” I have to admit I had never heard of such a thing. Nor could I fathom why anyone would want to do it. As difficult as it is for me to turn any rider away who is interested in improving his or her skills, my response was, “I’m afraid we have to say no.” I was concerned about the potential risk for this rider and others on the tour—especially knowing our tour would include some tight and technical mountain back roads with switchbacks. My decision to turn this rider away (along with a handful of his riding buddies) was based on my belief that riding with a car tire on a motorcycle could not possibly be a good idea or a safe practice. But I had to admit—and I did to this gentleman—my knowledge of the practice was extremely limited. I would need to learn more. As it turns out, that would require a trip to the Dark Side.

Behold, the Dark Side: A growing sect of riders that promotes the use of car tires on motorcycles

A car tire has a flat profile and is designed to stay flat rather than lean over. But Dark Siders claim they work fine and are cheaper and last longer than motorcycle tires.
A car tire has a flat profile and is designed to stay flat rather than lean over. But Dark Siders claim they work fine and are cheaper and last longer than motorcycle tires.

Dark Siders (they call themselves that) are part of one of the most evangelical groups of motorcyclists I’ve encountered. They are deeply passionate about their practice of using car tires in place of prescribed motorcycle tires on their bikes. And they are more than anxious to profess those beliefs in the hope others might also see the light. Or the dark, as it were. It borders on a religious movement. Needless to say, it was not difficult to get their side of the story. In fact, after I broke the news to the prospective student, I was soon flooded with emails from other Dark Siders, each enthusiastically sharing his personal testimony, telling of his conversion to a life of riding on the dark side, never to return to conventional practices again. “Remember, the earth was once flat too,” one Dark Sider offered.

Another went further to explain the extent of their mission, “Being that we are free thinkers, we push the envelope all the time trying new, different, bigger, winter, summer, truck tires on our various scoots.” These riders believe, rightly or wrongly, that car tires provide more economy and are less likely to fail than motorcycle tires. Some even believe them to be safer. Others were quick to accuse tire companies, claiming they know how to make motorcycle tires that last longer and cost less but, instead, scheme to make as much money on riders as they can.

Hector Cadematori illustration Dark Siders

Personally, I view motorcycle tires as high-performance tires and expect that to come at a price. When compared to their high-performance brethren from the automotive world, I have found motorcycle tires to be on par when it comes to performance, cost and wear characteristics.

Although it has spread to other makes and models, this movement appears to have originated among a number of luxury-touring motorcycle riders who claim to have experienced repeated motorcycle tire failures on these behemoth machines. Issues reportedly extended from very rapid tire wear to poor handling to blowouts and tire delamination (potential causes and preventive measures for these issues can be found in the accompanying story). So, some riders turned to car tires as a fix. And, once they found a shop willing to mount the car rubber on a bike rim, they began to accumulate miles without serious consequences (although most admit to the bike handling “differently”). The practice of mounting car tires to the rear of motorcycles began to expand and the order of Dark Siders grew as other riders were attracted by economics. Car tires, at least the ones they were choosing to fit to their bikes, tend to be less expensive and reportedly provide longer tread life. Predictably, some riders even began to mount car tires on the front rim, as well, and others have followed.

Dark Siders claim to have collectively ridden millions of miles on car tires without a reported crash resulting specifically from car tire failure (although there is no clear way of knowing if tire handling issues have played a contributing role in any crashes). One Dark Sider proudly claims that on one forum alone there are more than 1,000 touring bike owners who swear by them. Realistically, there have also been millions of incident-free miles covered by helmetless or poorly dressed riders, but I’m not ready to leave my gear at home simply because others have been able to do so without landing in the hospital or morgue.

Two BMWs. Both executing the same curve. Each with distinctly different handling characteristics and demands on tires.
Two BMWs. Both executing the same curve. Each with distinctly different handling characteristics and demands on tires.

BMW R 1200 GS leaning into a turnAdmittedly, I appreciate people who think differently. It is unconventional thinking that has led to some of the most significant inventions and greatest advancements in human history. Unfortunately, not all alternative ideas are good ones. In fact, most aren’t. The time I tried to use my walk-behind lawnmower as a snow thrower during one particularly bad winter comes to mind. It is true that necessity (or was it desperation?) often is the mother of invention. Just for the record, despite my own freethinking and stubborn determination, a lawnmower makes a horrible snow thrower. Even after you remember to remove the bagger. The point is, experimentation—especially when conducted outside of a testing facility and beyond the collaboration of industry experts—can have a dark side of its own.

Shedding light on the Dark Side argument: The industry’s view on the role of the motorcycle tire

In search of a balanced argument, I reached out to motorcycle manufacturers, tire manufacturers, heralded motorcycle safety experts and industry leaders to get their take on the subject. Not all are quoted here, but their input for this story was consistent.

A motorcycle tire has a round profile and is designed to handle cornering loads. But Dark Siders say they're overpriced and wear out too quickly.
A motorcycle tire has a round profile and is designed to handle cornering loads. But Dark Siders say they’re overpriced and wear out too quickly.

Before we delve into any comparisons to car tires, let’s first look at motorcycle-specific tires themselves and the role they play. One of the first things that the motorcycle manufacturer points to is the tire as a vital consideration in the overall design of a motorcycle. Tire choice is never an afterthought for the manufacturer. Quite frankly, it can’t be. Nathan Boyd, P.E., Director, Product Integrity at Harley-Davidson explains, “We look at the motorcycle as a complete system where the tires, the wheels, the swingarm, the forks and the frame are designed to perform together. Changing even one of those components can alter the bike’s intended characteristics.” So naturally, tire specifications are developed for each machine and then tested extensively to assure the optimum performance the product development team was looking for is achieved. Any deviation from that formula would potentially influence handling and safety. With so much thought, analysis and evaluation put into making sure that tires work as part of the bike’s overall system, it’s easier to understand why the factories urge riders to stick with what has been proven to work by highly skilled engineers, researchers and testers. Boyd punctuates that point. “As a motorcycle manufacturer, we feel strongly that use of tires outside our specifications is inappropriate, including using automobile tires on motorcycles.” Like all manufacturers, Honda has developed clear tire guidelines and specifies approved tires for its motorcycles, including the Gold Wing, and recommends that owners refer to their owner’s manual when making tire choices.

Even among motorcycle-specific tires, there can be tradeoffs when fitting non-specified tires to certain bikes. Imagine the potential compromises associated with installing a tire that was never intended to function on a motorcycle in the first place.

A one-track mind: The differences between car and motorcycle tires

According to Mike Manning, Dunlop Motorcycle Product & Marketing Manager, “There are several considerations when looking at tire design and use for a single-track ‘camber’ vehicle such as a motorcycle vs. a 2-track vehicle like a car or truck. Tire profile, construction and compounds are developed specifically for each type of vehicle.” Why? Because cars and motorcycles handle differently. A lot differently. Take a look at the images of the sports car and the bike negotiating the same sharp left-hand bend. Although both are BMWs, their handling—and the demands on their tires—are remarkably unalike. The bike leans into the bend, rolling onto the inside edge of its tires. The car remains relatively flat or leans out of the curve, placing the vehicle’s weight on the outer edge of the outside tires. Is there any wonder why the tires for each are designed differently to handle the unique forces placed upon them?

Motorcycle tires have a U-shaped profile and a contact patch that changes size and shape during cornering.
Motorcycle tires have a U-shaped profile and a contact patch that changes size and shape during cornering.

As the Motorcycle Industry Council puts it in its Tire Guide (developed in cooperation with the Motorcycle Safety Foundation and the major tire and motorcycle manufacturers), “Because a motorcycle is a single-track vehicle and leans as it turns, motorcycle tires are quite different than car tires. Whereas car tires have a fairly flat profile and a contact patch that varies little in size or shape, motorcycle tires have a U-shaped profile and a contact patch that changes size and shape during cornering.” The shape of a motorcycle tire is designed to maintain a consistent contact patch throughout lean. A car tire in this application would be flat and fat when upright and thin and narrow when leaned. “Car tires and motorcycle tires are constructed and designed differently due to the different ways in which they are used,” warns John Mosby of Kumho tires, one of the auto tire brands often selected by Dark Siders. “Kumho passenger car tires are not made to absorb the reduced contact patch at high camber angles that motorcycle tires frequently experience. Because of this, durability can be affected by operating at such high camber angles, which can lead to tire failure. We strongly discourage anyone from using Kumho passenger car tires on their motorcycle.”

The profile of a motorcycle tire clearly has one large-diameter ring in the middle that tapers to smaller rings at each side (creating the U-shape). As the bike leans, this makes rounding curves much easier than if the tires were square like those of a car. Here’s a quick demonstration. Grab an empty soup can from the recycling bin and a tapered coffee cup (that empty caramel macchiato cup will do nicely). Lay each on its side and roll them across the table. The can, shaped like a car tire, will track straight. But the tapered coffee cup, because it has larger and smaller diameters much like one side of a motorcycle tire, will want to turn. As you lean your bike from the large ring in the center toward the smaller ring on either edge, you are also in effect reducing the gearing of your bike, thereby slowing it in a curve. That makes it easier to add throttle through the bend as prescribed by most riding proficiency experts, which in turn stabilizes the bike’s chassis for smooth cornering. The square car tire does not provide that advantage when leaned.

Beyond tire profile, sidewall stiffness plays an important role in motorcycle tires. The sidewall acts as a suspension component and must also provide enough rigidity to not only stand up to the unique forces placed upon it during cornering, but to also take advantage of those forces for precise handling. According to Dunlop, “When the bike is vertical, the bike’s suspension system does much of the work in keeping the tire in contact with the ground and controlling the ride. When the bike is leaned, there is less mechanical suspension and more tire suspension characteristics at play. The bike tires are designed and constructed specifically for this use.”

Motorcycle tires are uniquely designed to maximize the contact patch for greater grip at all lean angles.
Motorcycle tires are uniquely designed to maximize the contact patch for greater grip at all lean angles.

Most modern motorcycle tires use multiple rubber compounds; harder compounds in the center to maximize tread life for highway riding and softer compounds toward the edges to maximize grip when the bike is leaned. Car tires have just one compound since they are not designed to be leaned over or to contend with camber forces.

While use of a car tire might have no severe consequences during normal riding, it could be problematic when performance really counts, such as when a threat unexpectedly appears directly in the path of the rider. The bike fitted with a car tire cannot be relied upon to respond as well as one with a motorcycle-specific tire when maximum traction and precise handling are needed. Is it ever acceptable to give up even a small degree of performance advantage when that small compromise could be enough to make an avoidable crash an unavoidable one? Stayin’ Safe founder Larry Grodsky once had a rider ask him if he really needed to wear protective gear. “No,” Larry replied. “Just wear it on the day you crash.” I suppose the same could be said for tires. Just use the motorcycle tires on the days when you need to avoid a crash.

The bottom line? The manufacturers, engineers and safety experts I spoke with all said the same thing; riders need to realize that this is not a good idea. The Motorcycle Industry Council puts it more directly, “Never mount a passenger car tire on a motorcycle rim; the flat profile of a car tire is incompatible with the dynamics of a vehicle that leans as it corners, and the section of the tire in contact with the rim (the ‘bead’) is incompatible with motorcycle rims.” A motorcycle calls for a tire that was developed to be a specialist in single-track vehicle dynamics. Dare I suggest that it’s not unlike the way brain surgery calls for a specialist in neurology. Would you turn to a gastroenterologist for that procedure because he or she has a lower hourly rate than a neurosurgeon? Both may be experts, outstanding in their respective fields, but neither would be a wise choice to fill the other’s role. As motorcyclists, we have need for a specialist: the one that was developed specifically for the demands of motorcycling.

The darker side of the Dark Side argument

Still not convinced? Even if you believe that running a car tire on your motorcycle fits within your acceptable risk threshold on the road, you may have left out an important consideration that can strike a little closer to home. Can the rider with a car tire mounted on his motorcycle have complete confidence that, in the event of a crash, he will be covered by his insurance? Or that others injured in a crash won’t target him with a costly lawsuit because he fit his motorcycle with tires that were not designed or intended for motorcycle use and may have contributed to the crash? Are the few dollars saved by turning to a car tire outweighed by the potential loss of a house and whatever dollars may be squirreled away for retirement?

As motorcycle safety expert and AMA hall-of-famer David Hough said during our recent conversation on this topic, “Motorcycle engineers get up awfully early in the morning to calculate what works best for bikes. An owner who disregards the engineers’ advice should think carefully about his or her talents in being more clever than the engineers. The owner who installs tires not designed for the task must take full responsibility for the results.” While the practice of fitting a car tire to a motorcycle may work suitably for some—even over many miles—there is no escaping that the rider must accept full liability for a practice that is not endorsed by the industry. Riders must consider carefully what accountability they may have as they openly encourage other riders to adopt a practice that is ardently discouraged by virtually all experts in the industry, including those who have no financial gains in selling more motorcycle tires.

Being a safety-oriented rider and writer, I’m inclined to make decisions that will limit my exposure to potential danger and to personal liability. While I am a huge proponent of creative and unconventional thinking, I am opposed to casual experimentation when life is on the line. Although I am tempted to trust the word of the many riders who have been able to clock thousands of miles on car tires, I place more trust in the collection of specialists working together on a daily basis to make sure that all components of a motorcycle work in harmony—not just to create a better rider experience, but also to avoid lawsuits due to product failures. So, upon careful investigation and consideration, my answer to the gentleman who inquired about taking our Stayin’ Safe on-road course with a car tire mounted to his bike would still be the same. Only now, I feel that I have done the due diligence to understand why.

(This article was published in the July 2012 issue of Rider magazine. Below are links to sidebars that accompanied the article as well as letters to the editor following its publication.)

Avoiding Tire Failure: Getting the Most From the Tires That Were Meant For Your Bike

Erasing Doubt: Car Tires on Motorcycles

Letters to the Editor: Dark Side


  1. (Although it has spread to other makes and models, this movement appears to have originated among a number of luxury-touring motorcycle riders)
    Sorry Eric, but you are wrong about where this all started. While I don’t endorse the practice I do know it’s been going on since at least the 50’s, (probably earlier) with Bobbers & Choppers. Speeds in rural areas averaged more towards the 45 mph range due to road conditions, and the bikes involved. A 45 ci Harley wasn’t very fast, and 50 miles was a hard days riding here in West Virginia. My Dad didn’t use car tires (He was too fast to trust them), but a multitude of his ridding buddies did. In the 60’s I had a bike with a 15″ rear wheel, and tried it too. Seemed to do OK to me at the time, but most of my riding was on gravel, and woodland trails. A skinny V W mud & snow tire, and I never got stuck in the mud.
    That was then. Now most bikes have no trouble doing the ton, and beyond. Even my old 650 Yamaha will do 110. Car tires? not anymore, but there was a time back in the good old days when motorcycling was fun & inexpensive.

    • I was going up Angeles Crest one Sunday morning and a big bike came up behind me kinda fast. So once I determined it was probably a Goldwing and not a cop, I stepped up the pace a bit. Then a bit more, finally I did the right thing and let him by. Ok it is a Wing with bags and a little flag no less. I should be able to keep up with this, right? Turns out he really know the road and I was more than a little embarrassed that I could barely keep up. Especially since I was in a new Porsche Cayman! After a little conversation at Newcombs Ranch he told me he was running a car tire from a Mini Cooper because they worked better and lasted longer. Alot longer. If that tire was not capable of handling the side loads I would have been calling the CHP for a rescue helicopter not avoiding them.

      • The tire may seem like it’s handling the side lpads but it’s not. That rider is simply pushing the limits of a tire not designed for a motorcycle and they are just lucky that it doesn’t fail. If they were riding two up with a fully loaded, or overloaded motorcycle, and most gold wing riders tend to carry way more weight than the bike is designed for, then the odds of something happening to that car tire increase. Just stating my opinion!

        • Being a long time darksider I can tell you that your fears are unfounded. Many of not most darksiders are running ZP (commonly called run flat) tires. So if your motorcycle tire will run for 50 miles with no air pressure in it then I would think your motorcycle tire is as strong as mine is.

          • i have lost two close friends from using the wrong tyre on their bike because a mate told them it was ok and ask their families if they wouldn’t pay the extra 80 dollars to get their loved father back !!

        • Your opinion is yours and you are entitled to it, no matter how wrong it is. I ride a 900#+ bike two up, loaded with an extra 75#+ or luggage, plus two riders weighing an extra 400#. I’ve gone through 2 car tires in 68k miles and I ride WV, E Kentucky mountain roads. You are wrong, PERIOD!

  2. In the words of vehicle dynamics expert Chris Rock…

    “Yeah, you can do it…but it don’t mean it’s to be done! Sh@t! You can drive a car with your feet if you want to; it don’t mean its a good f*%kin’ idea!”

    • On my third car tire and needing another, I will certainly stay on the darkside. simply because I can ride on it flat with two up. I ride daily and many miles in adverse weather and even horrible roads, that your weekend bikers would not even consider, all thanks to the “Darkside”!

  3. If dynamic limitations dominate the safety side of the car tire vs. bike tire argument, then a follow-up article should be done pitting a typical cruiser fitted with fresh motorcycle tires against a typical sport-standard fitted with an average sportscar tire if the appropriate width. Am I not correct in assuming that a modern sporting “standard” would still possess vastly superior dynamic performance, even when fitted with a sportscar tire? If so, then (in the absence of any evidence pointing to higher failure/pressure loss rates for car tires in motorcycle applications), the best advice from a safety standpoint would have to be first, not to ride cruisers, and then second, not to ride on car tires. Or am I missing something?

    • You are missing one other point. If motorcycle manufacturers are so carefully matching their products with adequate tires, how come virtually every customer replaces the universally crappy OEM rubber with vastly superior aftermarket motorcycle tires that better suit their riding style and their motorcycle? Why only those that don’t know better buy only OEM oil and filters?

      Let’s face it – all manufacturers will fit the cheapest OEM tires they can get away with, just like they’ll charge you a premium for generic oil with their logo on it. Sure, the bikes may be designed for and/or tested with said tires and oil but that doesn’t mean those products are best for them. At most, they are a (relatively) safe bet for those that don’t know better. Anyone who says different needs to get their head out of …

      • Sorry Vlad, you are wrong. Ducati uses Diablo Rossos….. almost all bikes come as a SYSTEM, engineered with certain tires installed. All new bike tests are done with STOCK OEM RUBBER. You couldn’t be more wrong.
        Except Harley… because with Harley, you just never know… LOL

        • Apples and oranges. Neither Ducati nor Harley are typical. It’s true that all new bike tests are done with OEM rubber. I have yet to read a test where they did not replace OEM tires with something different as soon as they were worn or even sooner.

      • Man, you hit that one on the head. My HD stock tires lasted like 5000 miles. R u , kidding? Replaced w/ after markets, 15k and still going. Next, Rider will try to justify why motorcycle batteries cost more than car batteries, and why most 2016 bikes cost as much or more than a car does. Since advertising companies comprise most of their profits, I doubt they would ever offer a better/less $$ alternative to advertisers merchandise. Car tires are great example. Rider would NEVER condone that! Even if it were true. Funny, that most bike reviews put on non stock tires, after a few miles. It’s all about politics, and not offending advertisers, just like the rest of the world.

        • Oh, and anything you do to save some $$ is always unsafe!! Helmets are only good for (X) amount of years, whether you drop it, or not. Oh wait, if you drop it from over 4 feet, it needs to be replaced. That’s what the manufacturers say, (at least with my helmet, a $500 Shoei). And it’s supposed to protect your head in an accident? Really? Etc., etc., etc.

        • I agree on the cheap OEM tires. I have a big 800+ pound cruiser and the OEM’s only lasted 5K. Subsequently got some Dunlap E3’s and they lasted 15K. Hence, got another set of E3’s and they are wearing well. I have always ridden Honda’s, 6 of them, and they are great bikes that mechanically have never given me any trouble. But the last one, even though it is a touring model, came with a cheap standard seat, and as indicated, cheap OEM tires. Hence, new tires after 5K ($500) and a new mustang seat with back rest after 1k miles ($650). So when I get ready to buy a new bike, those are two things I am going to consider intially. Based on 30 years of riding, Harley’s look better, and their OEM seats are nicer, but have higher mechanical maintenance. Alternatively, the Jap bikes, and I have looked at OEM seats on the Suzuki, Kawasaki and Yamaha, have cheap seats and sometimes don’t have the nice accessories that Harley’s do. So pick your poison. I love riding, and will continue to ride. One more comment, or really a question: Tires are too important to try and cut corners, but I am wondering about the possibility of a car tire on the back of a bike, but a motorcycle tire on the front? Just didn’t know if having the rounded tire was as important on the back as on the front. Any info would be appreciated.

          • Usually going double dark reference is to putting a rear motorcycle tire on the front.. reason, I couldn’t find a dual compound front tire for my wing, so found a dual compound rear, reversed rotation( because of the direction of braking forces, as opposed to acceleration on rear) installed on front and immediately got 15k as opposed to 5-6 on normal fronts. Even worn to slick on sides before tread wore out in middle

        • They went the liability route which is justifiable if wimpy. I change my stock 2007 HD Road King tire because it looked like a car tire and I didn’t enjoy the way it rode. Went with a Metzler 880 and proceeded to drag my floor pans around just about every corner. I also suffered a blowout on the rear from pushing the tire beyond it’s useful life. If I was ever to start logging serious highway miles I would feel comfortable using a quality car tire if the bead looks up well.

      • Manufacturers compromise. Thats why most people change out oem tires to suit their style. a company builds a bike and tries to determine the type of rider who will ride it. will they do long distance trips or twisties. are they tracking the bike, will they drag race or circuit race. then they put on a tire that will do decently on what they determine most of their riders will be doing. which means they aren’t particularly good at any of them but is capable. As for oils and filters I have often found oem to be cheaper than the aftermarket, but that just might be where I live. However oils are usually designed with additives based again on how the manufacturer designed other parts like the clutches and engine tolerances. Not saying aftermarket doesn’t make good stuff but I wouldn’t say OEM is always bad its just often compromised to cover the most bases. If you know what you want out of your tires and oil and filters than more power too you. lots of aftermarket companies create their oil to work with various motorcycle companies specs.

  4. I’ve been riding with a car tire for over 2 years with over 15,000 miles, rode twisties from Arkansas to West Virginia. I have worked in manufacturing for 25 years. One thing I’ve learned is that there are alot of technical, scientific or safety related reasons something should not work but you try it and it just does, I’d like to see instead of you telling us it should not work, do some actual riding/testing and prove it will not work.

    • Dave, I have been riding the darkside on my Yamaha Roadstar for the last 19,000 miles and love it. I think there is too much on why it shouldn’t work either. Hell, when I was in the Navy, I worked on Helicopters, and according to “Theory” they aren’t supposed to be able to fly either. Scientifically, they should never leave the ground…. but don’t tell Bell or Sikorsky that.

      I know I can ride 90 safely with mine. I have a higher load rating for riding 2 up with full saddlebags and luggage on the pack. I have better stopping power and that makes me feel good on wet or snow covered roads (I ride all winter in Wisconsin too).

      BTW, I only run a CT on the rear of the bike, and to start another argument, I run a MC rear tire mounted in reverse on the front… also adds more stopping power.

    • I’m glad to see someone use a car tire and prove it works. So far all I see are school boy idiots saying they would not recommend it with no proof or statistics OF ANY KIND! I ‘m tired of cycle tires that wear out every 7000 miles. Thank you for your input on this site!!!!

      • I’m sorry, but the fact that a number of people use car tires on motorcycles and are happy with them does not prove anything.

        Let’s face it – science and logic are on the side of motorcycle specific tires and darksiders have only anecdotal evidence and no hard facts or figures. We don’t – and likely never will – know how much less safe CTs are, but I think everyone with a sense of logic would conclude that they are less safe than motorcycle specific tires. Individual’s tolerance for perceived risk or trade-off would determine the choice. Consequences of that choice are not likely to affect anyone else but the rider and his family, so there’s no need to argue about it. It’s like arguing against skydiving.

        All that said, the next tire on my scooter will be a car tire and my sport-touring bike will remain on MT.

        • Doesn’t prove anything? Actual use sure does prove that car tires work. Safety is pushed so hard that even the slightest difference in danger is proclaimed to be ” a lot of difference”. Too much exaggeration! I’ve even had people tell me that Goodyear Speedgrips that used to be made had ” poor handling”. This after I had ridden 165,000 miles them and found NO handling problems. Those tires lasted me 18,000 to 20,000 miles besides. Too many people think they’re experts running their mouths off. I’ll believe the ones who use the tires long before I believe someone with a mouth and only an imagination. If someone runs a sportbike they may have a reason to stay with MC tires but they are usually kids and push their luck way too hard. After riding for 51 years I want a tire that lasts not one that helps me take curves at foolish speeds.

        • I’m a big advocate of car tires. However, in the absence of scientific research and concrete evidence my “seat of the pants” impressions are just anecdotal and I would never consider them definitive, especially not for other people. After all, I just rode 800Km of gravel on a scooter with a car tire, so I am not like other people :).

          All I’m saying is: Try it and come to your own conclusion. It’s cheap enough and definitely safe enough to do your own test. No amount of academic discussion, graphs and numbers means anything to those that tried it and liked it. Those scared of their own shadow are just trying to persuade themselves that they are not doing it because of safety concerns.

          • A lot of people with car tires I’ve talked to said they get close to 30,000 miles on those tires. I run Dunlop Elite 4’s on my GL1500 GoldWing and I get around 24,000 out of the rear tires and have gotten close to 32,000 miles on the front tire. I also pulled a camper trailer for 75% of those miles. That’s good enough for me.

        • I have not seen any CT user say it was responsible for the motorcycle accident and they won’t ever be doing THAT again. I’ve read a couple of folks say they tried it and it’s not for them. I can respect that. Everybody has a right to their personal preference. Everybody also has a right to the reasons they they apply to support their preference.

          Why do car tires on motorcycle rear wheels last longer than motorcycle tires mounted on same. If you are comparing tires of equivalent speed ratings the following applies:
          High power-to-weight ratio, speed, size of footprint and other aspects explain why motorcycle tires wear out quicker than car tires.

          This information was take from:

          Also taken from this site is the following:
          “Can I use a car tire on the back of my motorcycle?

          No. The design of automotive tires and motorcycle tires are very different. The profile of automotive and motorcycle rims are different with a different bead seating area. An automotive tire will not seat properly on a motorcycle rim, making it more susceptible to problems such as rim slip, which can cause balance problems.

          Motorcycles are designed specifically with a unique tread profile for leaning over when cornering. Under emergency or extreme maneuvering conditions, an automotive tire on a motorcycle may not allow the bike to handle as it was intended, which can lead to accident, injury or death.”

          This response is something of a mixture of truth and lie. To say “No” to the question posed is a lie. You CAN use a car tire on your rear motorcycle wheel. Folks do it all the time. The honest answer would be, “It is not recommended.”

          The rest of the answer is something of a mixture. The video above of the sports bike demonstrating handling performance while riding on a car tire should put the issue to rest as to whether cornering abilities are compromised with a car tire. Obviously they are not. While I do not ride a sports bike, I’ve toured my cruiser through the mountains and rural roads of West Virginia without problem and I’m not putting along.

        • “I’m sorry, but the fact that a number of people use car tires on motorcycles and are happy with them does not prove anything”

          Yes it does – it is called EMPIRCAL evidence.

          When the rear tire on my Nomad wears out, I will be most likely be replacing it with a car tire. If I don’t like it, then I will switch back.

          • I’d rather call it anecdotal evidence. You can find a larger number of people claiming that they’ve seen Elvis with their own eyes (after he died 🙂 ).

            I’ve been running a car tire for over 20,000Km and will never go back to MC tire. Many other people have similar experience – a vast majority of those who bother to share their experience. What makes them more believable is the fact that they have experience with both. It’s like when a car driver who never rode a motorcycle argues against motorcycles – the opinion of those that drive/ride both types of vehicle carries much more weight.

            So again, there is no scientific evidence until proper blind, placebo-controlled and randomized trial is performed, but that doesn’t mean we should listen to what those with no experience say..

      • I’m looking to buy my 4th CT, riding this one to the wear bar and beyond, with a nail in it and a slow leak. “Stupid” Maybe ; “Confident” beyond words! my last CT went flat 200+ miles from home, I rode it loaded down with no issues at all. try that on a MC tire.

    • I ran 2 rear hankook tires on. My ST1300. Got 20k out of each, could have stretched to 23k. Like it, no problems, if you’re a high miles rider, tires are a constant expense, along with the hotel in Tucson or Canada or wherever the core starts to show. I would run car tires again, and stop this dark side bs.

    • I’ve been on a Rear CT for 3 years and having it replaced after 37K miles with another CT. Have ridden the Twisted Sisters and Tail of the Dragon while scrapping floorboards, have had Bike up to 95 & 100 with no issue. Won’t return from the Darkside

  5. There’s one glaring inaccuracy in the article:
    “Predictably, some riders even began to mount car tires on the front rim, as well, and others have followed.”

    That’s simply not true. I am not aware of anyone who has mounted a car tire to the front wheel of their motorcycle. If you’re referring to those who do what is known as “Double Darksiding,” that is the practice of mounting a rear motorcycle tire to the front of a bike, not a car tire.

    The article seems to be a lot of talk and absolutely no action, intended to bolster only one side of the argument – The author’s belief that car tires on the rear of a motorcycle are a bad idea. Instead of writing the article from a desk, how about Rider magazine does some real-world and/or track performance testing to see how a car tire really stacks up to a motorcycle tire? Do the testing that all the manufacturers refuse to do?

    Tire and motorcycle manufacturers claim a car tire simply can’t work as well as a motorcycle tire because it wasn’t designed for the task. Riders who actually TRY it claim differently. There’s only one way to resolve it: Test identical bikes with car and motorcycle tires in braking, swerving, and handling tests! Test tire hardness and traction ability between MC and Car tires (did you know car tires are SOFTER?) and measure the actual shape and size of the contact patch on a car tire when used on a motorcycle.

    I’m not disregarding what the engineers know. The article is correct, they’ve worked hard to ensure the whole motorcycle works as a whole, and designed tires to work well for that task. However, just because something isn’t designed for the specific purpose doesn’t mean it can’t handle the task just as well, if not better in some respects.

    After the first rear Metzler ME880 Marathon motorcycle tire on my Kawasaki Vulcan 2000 only lasted 4500 miles before wearing out (flat in the middle), I researched carefully and decided to try a car tire (General Altimax HP) on my motorcycle two years ago, which I have ridden with for almost 8000 miles now. From my research and personal experience, I’ve understood that car tires are designed to take much more weight and much more strenuous forces on a car than they ever experience on a motorcycle. They provide better traction because of their softer rubber compound than a motorcycle tire. While the contact patch gets narrower when the bike is leaned than when the bike is going in a straight line, the sidewall “flexes” to keep a large contact patch on the ground when the bike is leaned over – the contact patch gets longer as it gets narrower, the tire never rides up on the edge or sidewall. I’ve already put almost twice the mileage on this car tire as I got out of the previous motorcycle tire, and have pushed the performance of this tire much harder than I ever did the MC tire. I have yet to be disappointed or find anything it can’t handle.

    I challenge Rider magazine to do some thorough investigation of the issue instead of allowing bias to determine the result.

    Frank LeClair
    Springfield, OR

    • ” While the contact patch gets narrower when the bike is leaned than when the bike is going in a straight line, the sidewall “flexes” to keep a large contact patch on the ground when the bike is leaned over – the contact patch gets longer as it gets narrower, the tire never rides up on the edge or sidewall.”

      A friend told me the same thing. I followed his Gold Wing with a car tire across West Virginia and observed the opposite. The side wall did not flex enough to keep the tread on the pavement. In every corner it rode up on the edge so that only a narrow strip of rubber was on the road. The more he leaned, the less rubber was on the road. At a stop you could see how the tread was rounded on the edges. This tread was not designed to be the only point of traction in a curve and was designed to act against cornering forces from the opposite direction.

      He kept the pressure low enough that I could see the tire deforming over bumps. This added a weave when the bump was in a corner. In spite of this, he claimed it held a steady line. After what I saw, I would never try a car tire on a bike.

      • Bruce,
        Great observation. I also have a friend that ran a car tire on the back of his Rocket III
        Tour. After it wore out, he changed back to the motorcycle tire. Even though he got about 20,000 miles out of the car tire, he said the trade off of poor handling in the curves (bike would not hold a line) was not worth the savings. Most everyone I have seen that runs a car tire, never comes close to riding a bike to its potential. It is just natures way of thinning the herd.

        • Actually… the 1st car tire I ran was a Goodyear TT and it had more of a squared profile and therefore caused increased counter-steer pressure.
          The 2nd tire (current) had a more rounded profile and handles very much like a MT.
          – Shorter stopping distance with CT.
          – When riding in the rain you can feel the traction.
          – Very neutral in handling, no counter-steer pressure needed in a turn.
          – More traction in turns… seriously.
          (I could break loose the MC tire anytime in a turn, but not on the CT)
          I have ridden all my life and instructed for the MSF and currently have near 70K miles on CT’s, I’ll not be going back to a MT.
          The bottom line… the CT works, and works well.

          • WHAT TIRE WOULD YOU RECOMEND FOR A Honda GOLDWING? Seems you have a bit more experience than some here, I do most riding on freeways,, No Tail of the Dragon anymore,, Planning a long road trip front tire will do the trip,, rear,, historically will not, Any advice would be helpful

      • Those guys are amateurs 🙂


        This doesn’t prove that you can ride on the sidewall all the time, but it shows that it can withstand more than double the normal car load at an angle no car was meant to be driven at. For a short time and at low speed, at least.

        Back to the matter at hand, I have nothing but positive experience with the car tire in all road/weather conditions and at any pace. There is not a single moment where I thought an MC tire would perform better, and I rode both back-to-back-to-back on the same bike. I only wouldn’t take it to the race track, but based on my experience while sport-touring on it I suspect it would perform much better than expected.

        From now on, my only response to naysayers will be to get some first hand experience or shut up. I don’t want to hear any more reasons why it shouldn’t work from people who are too cheap, to lazy or too afraid to try it.

  6. Well, with 10,000 miles on my 14 inch Bridgestone on the rear of my 09 650 Burgman, I can report no problems, very little wear, and I suspect at
    least 25-30,000 more miles of use. My daily riding is 44 miles mixed secondary and freeway. Darksiding seems to be a bit more popular with us scooter riders. Some have reported as many as 100,000 miles of “darksiding” on their scooters with no issues to speak of.
    If I were sport riding and touring, I would have stayed with the recommended scooter tire.

      • Dan, I’m riding a Bridgestone Potenza 165/65 R14 on the 09 Bergy 650.
        I have not changed the front from OEM recommendations, although I am on my second front tire. I have not seen anything on Bergman usa website about changing the front tires to an auto type. There may even be some clearance issues in the front as well..not sure.

  7. I’m a member of the luxury touring bike forum you spoke of in your story. (I call it a story as it produces no real world technical data to prove the claims of car tire use as a safety issue.)

    I am also a double darksiders , as I run a Bridgestone BT-45 battalax rear tire on the front wheel and a Michelin Primacy Alpin PA3 ZP. (run flat) on the rear wheel. I’ve always until now ran motorcycle tires on motorcycles . after long searches on each motorcycle I’ve had ,I finally found a tire combination for each bike that balanced tread wear and traction to achieve the best of both.

    The Goldwing is a completely different animal in those regards, it eats tires for lunch under normal riding conditions and when rode hard in twisties tires don’t last any time at all.

    So, I challenge you and the motorcycle tire manufactures to come up with a motorcycle tire that will give us long tread life, traction and the safety of a MT that you so claim at a reasonable cost.

    I also challenge you to take a ride on a Wing with a car tire mounted on it and give a real review of that experience , instead of the typical propaganda the tire manufactures are stuffing down your throat because they are paying your bills.

  8. While I agree with Eric’s reasoning on not using a car tire on a two wheeled motorcycle, those arguments don’t seem to hold for trikes. A trike doesn’t lean and the tires are subject to similar forces a car puts on it’s tires, so why not?

    • I agree, trikes only use a 3 inch patch , the rest of the tire is wasted. Why pay for special tires when it’s not necessary? Besides, all trikes have car tires on the rear already.

    • Trikes are not motorcycles in the strict sense of the word (they lean the wrong way in corners) and they do not use motorcycle tires on back wheels. You just demonstrated that you don’t know anything about motorcycles, trikes or tires on either. Just the right person to agree with this pathetic article.

  9. I agree with Frank…I think Rider magazine should do some testing on a GL1800 Goldwing with both a car tire and a motorcycle tire. Put it through the paces and even try them both at the track where the tires will REALLY be put to the test! Reading an article like this from someone that has not even TRIED what they are writing about is basically an insult to people that have logged hundreds of thousands of miles on car tires.
    Eric Trow is just another naysayer about car tires just like a lot of others were until they actually TRY running a car tire and really do some REAL WORLD testing with them and make an INFORMED decision on their use.
    Honestly it is beyond me why this article was allowed to be printed on heresay. I myself am now running a Pirelli run flat on my Goldwing and am loving it!!! The day that those experts on motorcycle tires make a RUN FLAT motorcycle tire…that will be the day a lot of darksiders might think about going back….or maybe not.

    • And if they do a test and you don’t like the results…. will you then find another complaint about that article….there is no pleasing you people….other than to whole heartedly agree with you on this polarized subject.

      • No I just wish that people make an INFORMED decision and comment on a subject they actually experienced for themselves before passing judgement on how unsafe something is. I have no problem with someone trying a car tire and then deciding it is not for them…where I do have the problem is people with the doom and gloom attitude on something they know nothing about!

        When you say YOU PEOPLE…obviously you have not experienced it either. If you don’t…that’s ok. I know how it is and the safety of a run flat not to mention the higher load bearing tire. I am happy with my decision to run my car tire.

        If they test the tires and compare them to the hottest motorcycle tires I can bet they will be very surprised.

        • Actually, Seventhson appears to be one of the very few people who tried a car tire on his machine (Yamaha Stratoliner) and didn’t like it. Had some stability issues (a wobble at higher speeds) as well as didn’t care for the way the car tire “wallows” in highway ruts, or other road surface irregularities.

          I’ve had my car tire on my Vulcan 2000 for about 8000 miles now without any complaints. The way it handles uneven surfaces like highway ruts or pavement seams is a minor inconvenience compared to the other advantages like increased traction, much longer tire life, and smoother ride. Solid as a rock at high speed, (even stable at 70mph on gravel!)

        • I currently run the Pirelli Eufori 195/55 R16 on my wing. I have about 6500 miles on it so far and not one instance of instability or problems with cornering. It does tend to follow groves in the road at low speeds like coming up to a stop light at times but overall has been a great tire. My next tire will be the Michelin Primacy Aplin which has been dubbed the closest to a MT.

          The thing that sticks in my side are the ones that say you will crash and burn running a CT and have never tried it for themselves. I would love to hear if anyone can remember any car tire delaminating…I can tell you of MANY MT’s that have done so and the flat spot that forms on MT’s give them a weird feeling when cornering.

        • Consulting engineers from both motorcycle and automobile tire manufacturers is in fact making an INFORMED decision. The automobile tire manufacturers clearly state their tires are not designed for motorcycle use.

        • Sean,

          The Hitachi Magic Wand was also not designed for what your girlfriend uses it for but if it gets the job done better than you do shouldn’t she use it?

          Bread was not designed to hold slices of meat, I don’t see anyone complaining about sandwiches today.

          I could pick so many things apart about this article it’s not even funny. Perhaps I will do a detailed breakdown of this article later and point out the many flaws, misinformation, out right lies and how about every other sentence is worded in a manner that drips with disdain towards those who choose to run a CT.

          You can tell that this writer never checked into darksiding for the intent of giving it an unbiased chance. He had his mind set before he ever started researching. His ungrounded hatred toward it seaps out in almost every sentence.

          This article is great for one thing. Showing who the real zealots and religious nuts are.

  10. I too spoke out against the use of a car tire on a motorcycle. The article is skewed in that they asked Dunlop Motorcycle Manufacturers what they thought. Of course they would be one sided. The facts are I put a Michelin Alpin PA3 Car Tire on the rear of my 2010 Goldwing with a Bridgestone B709 MT on the front. Why to prove the Darksiders wrong. Three months latter and I have proved myself wrong. The tire has a more round profile very simular to the Dunlop D250 MT. The Michelin stops better, takes curves BETTER than my old MT, has a larger contact patch, is a runflat and can be run with no air, is safer in the event of an air leak, is smoother and does not cup. This article is total crap as is the magazine.

  11. This article has not been technically researched, in my opinion. the people referenced were not engineers or manufacturing types but were marketing and company representatives. So we have a ‘journalist’ spewing opinions from others …who have opinions. We also have people who are stating facts that they have done it and the results of doing it. your magazine is becoming less creditable.

  12. The problem with your theory is that certain car tires actually work very well on big touring bikes like the Gold Wing or Electra Glide. They work so well that you can take them to a track day and fly around corners raising sparks. Check YouTube and see for yourself.

  13. Dunlop seriously needs to go back to making car tires, we call them DUNFLOPS for a reason! They make tires for the manufacturers of the motorcycles so they have a contract. The quality is subpar, the handling is terrible and the amount of mileage I get is about 4500. I agree with the other readers here you should do some testing! You should at the minimum ask someone other than DUNFLOP mfg. The worst MC tire ever made!

    • It’s not the price, but durability and longevity. Catastrophic tire failures are not rare on Goldwings and motorcycle tires don’t last long on them anyway. if you can’t afford a Goldwing, don’t question decisions of those that can.

  14. I read this article with much enthusiasm because I have a co-worker that runs a car tire on the back of his highly modified Triumph Rocket III. He swears by it, mainly because he’s pushing well over 200 hp at the wheel. Everything he has said about running the car tire seems to fit right in with what the article states. Very interesting stuff!

    • I own a 2008 Rocket111 and wore a flat 4-5in flat spot in 3000 mile Granted I was loaded to heavy but that’s the point of my considering a car tire Please let me know what you have been using so I can look into it

  15. In regards to insurance coverage, if my Triumph and BMW call for Metzlers and I use Dunlops of the same size and ratings because of cost and possible mileage gains, am I also screwed in the event of an accident? I switched to a car tire rear on my Rocket 111 and after a short learning curve am quite happy with it. It does handle differently because it is quite wide but two up it is just as flickable as with the old Metz, which was fubar at 6000 miles. I have 10,000 on the CT with no discernable wear or problems…and it cost a hundo mounted.

  16. Since when does Rider magazine write articles for the sole purpose of mocking a large group of riders because of their equipment preference. The author was intent on insulting this group rather than providing any actual test data or trying to understand why car tires on motorcycles has become so popular.

    The author says he has never tried a car tire, so how would he be qualified to make a judgement. He’s not. This was simply an article about his opinion, not fact.

    As a result, this is one long time subscriber who will not renew. Roadrunner is a far superior magazine with great touring articles and downloadable GPS tracks.

  17. Agreed, complete opinion piece. I did over a year of research prior to going to the Dark side. On my cruiser, I will never buy a MC tire again, at least not until the tire prices come down and the longevity comes up, and maybe not even then, as they simply don’t have the contact patch of a CT. Hey, check this out, too- There are still many MC tire blowouts, delaminations, and general tire failures. Can any of you remember the last time you had a car tire fail you from manufacturing defects? I do recall Firestone had a bad go with some tires Ford was using in the early ’90’s, but that’s about it. The overwhelming majority of car tire failures are from road hazards, potholes, nails, screws, gashes from debris on the road, or significant others potentially tearing them open with a kitchen knife! They also fail occasionally due to dry rot. When’s the last time you saw a MC tire with dry rot? Never, if it’s ridden with any frequency. Why? Their tread surface wears out long before the rubber compounds begin to deteriorate.

    I can also tell you that his tin can/styrofoam cup “test” is invalid. Simply go on Youtube and search for video of darksiding motorcycles. You will see, even in full peg-dragging cornering, there’s still almost 50% of the tread surface contacting the road!

    Sorry, I won’t believe a story written by someone who did no actual research, has not experienced it, and relied only upon those who stand to lose money or business by endorsing this. I have contacted my insurance, and been informed that if the tire is DOT legal, there is no problem with coverage.

    Eric Trow, stop the fear-mongering! I don’t tell anyone they should go to the dark side. However, if you are considering it, there are a ton of resources out there for your education. Utilize that prior to making your decision. Don’t base that decision on an ill-informed opinion-filled story.

    San Antonio, TX

    • There is no research supporting or debunking this. One thing I couldn’t find on youtube is breaking in a hard corner on a car tire. That tire changes geometry based on load and rotational speed, I am concerned with that effect on an emergency brake in a hard corner. (might be a nil effect because you have to straighten up to stop on both tires)

      I will stick to motorcycle tires but to each his own, my real concern is that the people I ride with will maintain their third party liability. Good to hear that your insurance company is ok with it, who insures you? Just so I can pass it on to the car tire riders in my group.

  18. There is an issue that the article failed to address, and that is “load factors”. With these ‘behemoths’ weighing in at heavy, plus a full-size rider and their full-size SO as a passenger, there is no weight left over to fill the tank without overloading the MC tyre!

    If the manufacturers are designing their machines from the tyres up, then they should make sure the tires that they are selecting are able to carry the loads that their machines are required to carry.

    I looked at this article hoping that it would provide balance, and found it full of opinions, hear-say, and advertising-speak that does nothing for the reputation of the author or the magazine. Grow up, or give up! There is no room for articles of this poor quality, content, or just plain annoyance on what should be a serious discussion with both sides plainly put, backed up by real world experience.

    I would suggest you give up your day job, and ride some to get some knowledge before you write again.

    Len in South Australia

    • Very good safety point, Len. My ’13 Wing lists the payload as #410. This includes everything you put on or in the bike. Don’t forget the added on parts and accessories! I’m sure that two up I am way over the limit imposed by Honda. So I have to make the decision to ignore the load limit of the bike if I am going to ride. The Michelin run flat care tire at least gives me a slight safety margin in that it is rated for more weight and it is a run flat design. With the tire pressure monitoring on the bike, I have some warning also. I never try to convince anyone to go to a car tire, but I will share my personal reasons and experience about it. A sport bike or high performance bike could probably go beyond the handling capability of a car tire, but a Goldwing or Ultra Classic will start shedding metal components as sparks long before the limits of the tire can be reached. I sure would like to see some real testing done about this. Anyone reading this understand I am not telling you to do it. And please don’t admonish me for doing it. I respect your right to choose, so please do the same for me. Thanks!

  19. I too have plenty of experience with a car tire on my Star Stratoliner (General Exclaim 205/55-17) It was a mistake….period. The wonderful handling of this low centre of gravity bike was no longer there. I have read from those who promote this foolishness that it “just feels different”….well “different does not come close to describing the way the straight line tracking is adversely affected by imperfections such as road patches, grooved pavement or lane furrows that are created by heavy truck traffic etc…etc…etc…Every day riding is just not as enjoyable with a square profile tire….here is why…
    With M/C tires front and back, your bike tracks a single line, but with the square profile rear tire you are now riding a narrow triangle. This is the source of ALL the straight line handling problems. Take the truck lane furrows that I mentioned earlier….the side of the square profile that is in contact with the furrow steers the bike in the opposite direction. In other words, when the left side of the rear tire is in contact with the furrow, your bike wants to lean right and vise versa To avoid this greasy, wobbly feeling, you end up riding the centre of the lane, where the pavement is somewhat flatter.
    My strong recommendation to less experienced riders…DON’T DO IT !!
    My bike also demonstrated a severe high speed wobble that was not there with a motorcycle tire. Those of you who promote this foolishness should keep you’re opinions off the internet….as you have no idea how a car tire might affect a motorcycle other than your own. Motorcycle manufacturers carefully select certain tires for their bikes. The choices they make come from hundreds of hours of R&D. The wrong tire choices can be adverse and worse…unpredictable and dangerous.

    • Perhaps you chose the wrong tire to run on your bike. On gold wings the tire choices that are popular and work well are the Kumho run flat, the Perelli Euforia run flat, and the Michelin Primacy Alpin (winter snow tire). The Michelin is the latest most popular tire because of it’s rounded profile edge that many people are saying performs like a motorcycle tire. At least you tried it and found it was not for you…unlike the person writing this article.

      • So…. in other words picking the right car tire for my bike is a crap shoot. Maybe some riders are willing to compromise and maybe others actually have found the right car tire but from the extreme way it altered my bike I just think most dark side riders accept the handling compromises to save some money.
        I guess my main point here is that sooner or later….or maybe it has already happened….some poor sucker is going to install a the wrong car tire, hop on the bike and kill himself.

        • I think most people these days know how to use a computer and can look up about the subject. In doing so they can come across forum that are for darkside riders. There they can ask all the questions and talk to people that run certain tires and make an informed decision from people that put thousands upon thousands of miles on these tires.

          Here is one of them for gold wing riders for example:


          AS far as compromise…I really do not know of ANY compromise I am having to deal with with my tire besides at 5 mph it wants to follow groves in the road like coming to a stoplight. There is minimal more effort on turning and really I cannot tell much of a difference at all.

          I looked up all the information before I decided to go darkside and asked the people on the forum etc. The rest is history and I am happy with my choice.

        • Many a poor sucker have hopped on a bike and killed themselves, and not because of a d.o.t. Approved tire. I write from experience, I have put many miles on a cruiser of mine using a car tire on the rear. Now, I am on my second Goldwing, a 2012, and will continue this practice. I have been riding since 1972, and can tell you for sure that there are many safe habits one can practice that very well could save your life while cruising. There are many individual choices to be made, the right bike for you, fit, and what type of riding you enjoy. The choice to stay not only sober, but free of alcohol. I would think that with the huge possibility of harm while enjoying one of our favorite pastimes, then why would one injest anything known to slow down your response time ! Arn.

        • “So…. in other words picking the right car tire for my bike is a crap shoot.”

          No, putting a tire on your bike without doing proper research is a crap shoot.

          Simple logic tells you that using what many other people have used before and have had success with means it will likely work for you as a well.

    • I am not a darksider but find the idea and physics interesting. I have been reading a lot of the replies here and one point that needs to be brought up is that a car tire’s tread now a days is directional. So when it is mounted on a motorcycle, I believe it HAS to be mounted as if it was a left rear on a car. Mounting a tire so the tread and sipes are backwards would probably cause some of the handling issues you bring up and VERY bad in the rain.

      • The Michelin Alpin Z ( or run flat) is a directional tire. Most other tires used on bikes as “darkside”are directional. Just put the arrow on the tire carcass in the direction of rotation. They don’t make directional tires for each corner of a car, just an arrow showing rotation direction. I’m not sure what you mean by mounting “as if it was a left rear on a car tire”.

    • If you experienced wobble that wasn’t there previously, that should tell you that you either got a defective tire or it was not mounted/balanced properly. I have installed literally hundreds of tires during the course of my automotive career and have seen the end result of some very expensive tires that failed prematurely because they were not installed correctly or were new defects. I am also a rider spending $500 every 12-15 months for tires. There has to be a better option, maybe a car tire.

    • Thank you for sharing your experience, it’s good to finally hear from someone who tried it and didn’t like it. However, choleric tone, name calling and bad grammar do not help promoting your view. More details about the tire you used, pressure you ran it with, distance, etc. might.

      So far, all we have is one exception. It may as well prove the rule, especially when presented like that.

      I found that lower pressure improves the handling of the car tire to a great extent. For example, a 25psi car tire performed noticeably better in fast sweepers (120-140Km/h) than MC tire at 36psi. No other characteristics were negatively affected except maybe tire wear, but it’s already beating the MC tire by at least 3/1.

      Tire: Achilles Platinum 7
      Bike: Yamaha Majesty 400
      Distance: 4,500Km asphalt, 800Km gravel
      Conditions: dust/sand/gravel, hot asphalt, wet and dry

      There are no conditions under which I would prefer a MT over CT on my scooter and I rode each for at least 5,000Km during the same season.

    • Note that a Wing is about 100lbs heavier than your Stratoliner…and, notably, a WIng is a very rear-heavy bike! The rider sits well behind the engine, the fuel tank is set back, the pillon rider is right over the rear wheel, and all the gear is carried on the rear tire.

    • Thank you for your opinion, absolutely devoid of any experience or facts.

      The fact is that thousands of riders have tried it, for millions of accumulated miles, with no evidence of it being unsafe.

      Seventhson’s experiences he relays in a previous comment are one of the few negative experiences I’ve heard of. Myself, I’ve ran a car tire on the rear of my Kawasaki Vulcan 2000 for about 8000 miles, and the handling on highway ruts or uneven pavement is fairly minor and the only negative aspect I’ve found so far to the car tire.

  20. Having been around the block a time or two the only part of Eric’s article that has any substance is the first paragraph, which like a few other subjects will only bring out the worst and for unfortunate reasons. Not currently a DS’r there are a few points I take issue with on a diatribe such as this.

    First it is difficult to embrace such an article when it is presented so lopsidedly, opinion will never stand up to something well researched. Research in this situation requires something more than a few emails and talks with industry insiders. On example being the presentation of potential insurance issues, I made a quick call to my agent, who is with one of the nations top 3 insurance providers and he understood the issue and stated there was no weight to the potential of not being covered. Research is work and generally requires more than calls and emails. I doubt Rider does nothing less when performing road test and comparisons of equipment.

    Secondly, much ado is pushed on performance, exactly what are we talking about here? Aren’t the majority of motorcycle (and cars for that matter) engineered way beyond the max performance the average or even above average rider can use? Even if the average rider had the skills to maximize a bikes performance, where could they do so, not on any of the roads you and I use day in and day out. It seems fairly simple to deduce that even a car tire can handle any performance the general motorcycle population places on the average bike

    Thirdly, there was discussion regarding “handling differences”. So what does THAT mean; allow your tires to drop in pressure=handling difference; new tires vs old tires=handling difference; ape-hangers= handling difference, hard tail vs soft tail= handling difference, shoot cruisers vs sport vs touring vs standards = handling differences. You pays your money and you takes your chances.

    In conclusion, Eric wraps up saying he had done ‘due diligence’, personally I believe that from the responses here we can see that is far from the truth. Honestly the only thing accomplished here was mouthing the words of marketing insiders, we live in a world consumed with litigation, I doubt you can find one manufacturer of anything that would endorse the use of their particular product for something other than what it was made for. They can’t, it would open up a court room door. The by line of the article uses the word nonconformity, maybe it is about time to look at that word as something to embrace rather than ridicule, if my memory serves that was one of the principles that made this country great. Shoot to most of the driving public motorcycle riders are nonconformists to the max, DS’ing is not for everyone, so be it but lets not throw the baby out with the bath water simply because we heard it was the thing to do. Eric is a better writer than this and I believe that Rider is a better magazine than this, next time either go the full monty and truly do due diligence or allow sleeping dog to lye.

    • I agree with Norm and the eloquent way he put his thoughts into words. While searching the web for information about DSing I came across this article. Eric Trow does nothing but tell me how against a CT on motorcycles he is.

      I have been considering DSing with my 2010 wing after a trip of 2500 miles, riding 2 up and pulling a trailer. I noticed after the trip my rear tire was flat in the center. A CT may be the solution to this but I would like more information before I make that decision.

      Information is key!

      • This information should be taken as a guideline and not fact (disclaimer here).

        Having information is key but getting it is a task! If you want honest information on the subject, do not accept the opinions of those who have not tried a car tire (CT) on a motorcycle rear wheel. Invariably you will find articles like the one posted on this site that start with something to the effect that “we’ll take another look at the idea” and regurgitate the same old opinion. Initially you are left with the thought that the author MAY have tried it! But as you read on you discover that they have not because (this is implied in anything any expert ever says on the subject) it is too dangerous.

        One place to go for direct information is here:

        Youtube has plenty of videos from folks who have are using CTs. You can even find some folks running them on sport bikes!

        I have about 20,000 on my CT which I put on an 1999 Yamaha Royal Star Boulevard. It’s probably good for another 5,000 miles or so.

        As to why the tire on your Wing is flat in the center after 2,500 miles:
        most of your riding is done upright so most of the time the weight is being supported by a very narrow section of the tire width. Narrower tires wear faster. Wider tires wear slower. Because a motorcycle tire does not provide the full width of the working face of the tire for the bulk of riding it is like riding on a much narrower tire.

        The question is this, do you REALLY need a tire with rounder shoulders on a motorcycle to make cornering possible? Watch the youtube videos of folks demonstrating this very concept!

        Folks Dark Siding or considering the practice do so for one reason only, they put a lot of miles on their motorcycles and do not want to replace the rear tire every couple of months or so.

        I’m sure that in your case, if your rear tire could last an entire year of use the way you use your bike, you’d stick with a motorcycle tire (MT).

        It all comes down to this, why do rear motorcycle tires wear out faster than car tires? We ask this question after hearing that CTs on motorcycle rear wheels last many times longer than you average motorcycle tire in the same position.

        There is a web site called Dunlop Motorcycle Tires that answers this question. The wording and presentation have gone through minor changes. I will paraphrase the points which they used to provide in a bullettted fashion:
        – the speed of the bike
        – the power to weight ration
        – the size of the contact patch
        – other factors

        When we opt to use a CT on the rear wheel of our bike we change the size of the contact patch making it larger/wider.

        Why does a wider tire last longer? Among other things, a wider tire distributes the load on the rear wheel across more surface area at any given instant in time. This increased load bearing cross sectional area loses tread depth at a slower rate for any given usage than a narrower tire used in exactly the same fashion. Just take a look at all high mileage car tires and you will notice that they tend to be wider tires. Wider tires increase rolling resistance so reduce fuel economy. It all comes down to trade offs. If you want a higher mileage tire you will get somewhat poorer fuel economy. If you want better fuel economy you may opt for a tire that does not last as long.

        But what about rubber hardness? OK what about it? All substances have frictional properties. These properties are reflected in tables that contain the frictional coefficients of substances. Rubber is no exception. Substances that provide greater friction have higher frictional coefficients. Softer rubber provides higher friction that harder rubber. As rubber heats up it gets softer and has more grab. Things with greater friction wear more. Car tires driven at higher speeds wear faster because they have greater friction. it has been theorized that wider tires wear better because the provide a larger heat sink for the tire to dissipate and so run cooler.

        You do not want to make a tire too hard as it will not hold the road well under cold temperatures. As rubber cools down it gets harder and looses friction. You would think your average high mileage tire would be designed for all weather operation, i.e. it would perform acceptably for winter use. This being the case it would not be prudent to increase the hardness of the rubber to accomplish the greater wear feature. Don’t alter the hardness but do change the width.

        One person I know believes that car tires last longer because they are harder, sacrificing friction. They argued that motorcycles needed more friction so used softer rubber which was why they did not last so long. In the same conversation they told the story of somebody on a sports bike who pulled out of a parking lot on a cold day. The dumped their bike when they went around the bend because the cold bike tire did not grab the pavement! So obviously this is not a cold/all weather tire.

        My tires hold up pretty good when I pull out of drives on cold days (below freezing). These are both CTs and MTs, but I am not riding a sports bike, I’m riding cruisers with more standard tires. Winter car tires are made from very soft rubber and you can guess why.

        I wrote an article about tires on my own site which you can check out if you want:

        Do motorcycles need more friction than cars? Who knows, but all things being a trade off you should analyse the compelling factors and choose accordingly. I know from stories and conversation that many sports bikes come with harder rubber tires. From the story told above and from a coworker who told me the tires on his sports bike did not work below 40 degrees fahrenheit

        We could argue that a smaller, lighter vehicle could need tires with a greater frictional coefficient to compensate for their lightness but here is an article that questions many things (make sure to read comments):

        Their may be some things left out of the following but it will get the point across:
        to stop something a frictional force must be applied equally against the momentum to neutralize it. Let us express momentum as kinetic energy, Ke. So Ke = 1/2 mv^2.

        Read that as 1/2 the mass times the square of the velocity.

        Whatever mass there is. moving at what ever speed it does, their needs to be a force applied sufficiently to completely neutralize that energy. This fore would be friction. it can be roughly expressed as follows:
        F = cmg.

        There are a few things missing from this equation but it can be used to demonstrate one thing. The equation is read as follows, force = the frictional coefficient times the mass times the force of gravity.

        So we have a crude but incomplete equivalent as follows:
        1/2 mv^2 = cmg.

        We can do some algebra and the mass drops out to produce:
        1/2 v^2 = cg

        For breaking purposes the big factor surrounding breaking is NOT the weight of the vehicle BUT the fictional coefficient of the rubber. If you read the previous article you will note that it may be that with all other things being equal, a lighter vehicle may get stopped sooner.

        So it all boils down to application. Make sure your tires perform properly under the conditions in which you intend to use them. A good rule of thumb with respect to traction of a CT on a motorcycle would be:
        if it works well on a car under a given set of conditions it should perform similarly on a motorcycle. My car tire works OK on the back of my 1300 Royal Star boulevard at 17 degrees fahrenheit.

        Make sure you study the dark side database and pick a tire and inflation range found to work on your bike.

        • It’s not as simple as you tried to explain it. You are missing a few key components in your stopping distance equation this different contact patch size does affect down force as does tire compound. With motorcycle tires if you get long life out of it you don’t stop or turn as well based on shape and contact patch. I fail to see, even with these manipulated formulas, how car tires can last longer and still outperform a motorcycle tire.
          You have a dead link in your support documents as well another includes the following on their main page “If you choose to put a car tire on a motorcycle, you do so at your own risk.” Doesn’t sound like the lawyers supporting that page support their position, nor does it inspire confidence.

  21. After viewing the Rider magazine & website- It’s obvious why they won’t give a fair opinion on using a car tire.

    Motorcycle tire mfgr’s advertise on the website!

    Rider won’t bite the hand that feeds them.

    Where would this country be if everytime a new idea came up, we were told it can’t work! And we believed them!!

  22. Hey look…I can understand trying to save some money by putting a car tire on you’re bike…I tried it myself with very poor and possibly dangerous results(bad straight line tracking and worse….severe high speed wobble), but to promote this foolishness on the internet as the answer to those evil tire manufacturers who refuse to make tires that last as long as these guys think they should?? Some of these guys are like religious zealots…disagree with them and their heads explode. I know that a lot of these guys say “it’s not for everyone” and I respect that…but please do not promote this as a sound alternative to dedicated M/C tires. Roll the dice for yourself but do not encourage others to. That is all I have to say….ride safe.

    • Again…did you research for the proper tire? Did you go on forums and ask questions etc.? You make us out to be some kind of cult when all we all want to do is ride safe, not have our tires delaminate on us or get flat spots, and be able to bring us home safely. I can only speak for how it affects my gold wing because it is the only bike thus far that I have mounted a car tire on.

      On the flip side…just because you had a bad experience with the tire…doesn’t mean others will not have a great experience. That is why all of us should make INFORMED decisions on doing things with our bikes. In the end you will do what you want and I will do what I want.

    • Yes; I get it that you tried DS and didn’t like it… I don’t like Bridgstone MC tires, so I switched brands for many of the same reasons you stated you don’t like DS tires… so what?? that doesn’t mean all BS tires are bad…. I just didn’t like them on my bike… your free to do as you wish… it’s just that your experience is so rare, that it causes suspicion regarding something you did wrong with your tire selection, installation, balancing etc… I’d look there first before dismissing DS out of hand

      As far as this article goes… it is the same old tired and moronic “Opinion Editorial” writing that is so common… he stated he believed it was a bad idea before he even wrote the one sided article and then set out to justify his “opinion” with “industry” experts who have a financial vested interest in maintaining the status quo… none of them stated they have ever ridden a bike with a DS tire on it and he never rode a bike with a DS tire on it.

      All of his self justifying opinions reached without doing any side by side comparisons of similar bikes with MS and DS tires on them to actually come up with any useable knowledge… worthless, worthless, worthless and he should be ashamed to claim the article is anything more than an OP-ED hatchet job piece of drivel.

      considering who pays his salary through advertisements in his magazine, I would have expected nothing less than this garbage…

      Give us some facts!!, side by side comparisons!!, tests of traction, cornering, smoothness of ride, stability etc on cruiser type MCs where DS is most often used… (not street bikes)… by people who are unbiased and are seeking the truth… please!!

      • Actually I did hunt around for opinions as to which tire to use and the Exclaim UHP was one that came as an excellent choice….obviously those who recommended it were willing to accept less than the best regarding handling and stability.
        BTW….you want an opinion on balls out board scraping handling?….That same tire was very twitchy at the limits. I now ride my bike with full confidence…something I sorely missed with the car tire. Sometimes you have to switch back just to recall what was missing.

        Also…I must say, Eric Trow’s opinions were just that….opinions…and I guess maybe he should actually climb on a Dark Side bike as a way to redress the comments of Darksiders that have commented here.

        So how about it Eric….
        will you give these guys an updated, educated opinion. As much as I dislike the Dark Side tire myself, maybe you’re the man to enlighten us all with an article/opinion with some personal seat time on the Dark Side.

        • I can’t disagree with what you’ve said here… you tried it and didn’t like it and you made an educated decision based on your experience… no one should question that.

          I was sceptical when I first tried a DS tire, but for me and my experience with two different DS tires on two different Cruiser MC’s for a total of 40,000 miles of riding on DS, I have been very happy with the ride, the performance and the longevity and have noticed with both bikes, that the DS tires stopped me quicker, held the road better on turns with wet or with sand/dirt on the road and gave me an overall smoother rode going down the road…
          I purchased both these bikes new, and replaced the original OEM tires with DS tires on both bikes when the OEM tires wore at at 6300 miles. The rate at which these OEM tires wore out was shocking! and I don’t ride that hard…
          I believe that if enough riders go DS on their Cruisers, eventually the MC tire industry will have to wake up and build tires for big heavy cruisers that get something close to 20,000 miles on a rear tire… until they do, they will see more and more Cruiser riders going DS….
          I know of no one who has had an accident/injury that was show to be directly related to using a DS tire on a cruiser type MC… does anyone??

          I believe that people who write articles for magazines with a bias, need to state it (he sort of does on this article in the intro) and if there was no research done, no new information brought out, no side by side testing done, then just state at the beginning of the article that your writing and OP ED piece about why DS tires are bad, so people don’t waste their time reading an article with NO useful information in it…. wouldn’t that be refreshing!!??

    • Seventhson,
      I appreciate the fact you tried a CT before climbing onto the anti-car tire bandwagon. However my experience could not be more different than yours. At this time I have a little over 101,000 miles on my 2002 GL1800, approximately 77, 000 of those miles have been done using four different car tires on the rear. I believe that I have given up nothing in safety, comfort or handling by using a car tire on my rear wheel. You feel your test of a car tire makes you an expert on the subject, my use of four different car tires over 77,000 miles makes me more of an expert on the subject than you.
      I admit that back in 2007 when I first heard about someone putting a car tire on a motorcycle I initially thought it to be a dumb idea. The more I read about it the more curious I became so, like you, I tried it. As it turned out, I liked it.
      You stated, ” I know that a lot of these guys say “it’s not for everyone” and I respect that…but please do not promote this as a sound alternative to dedicated M/C tires.” Fact: car tires work on many bikes and in truth they usually work quite well. That is irrefutable. Fact: there is nothing intrinsically dangerous about the practice or it would have become evident by now given the fairly large number of people doing it on a wide variety of motorcycles. It does appear to be a sound alternative to dedicated motorcycle tires in many cases. Every handling quirk, or characteristic you assign to your use of a car tire could just as easily been caused by a different brand of motorcycle tire or a faulty motorcycle tire. Not all car tires are alike just as not all motorcycle tires are alike.
      The fact that you have become such an ardent opponent to the use of a car tire on a motorcycle makes me wonder what your agenda really is. You charge others with extreme reactions. ” Some of these guys are like religious zealots…disagree with them and their heads explode.” Remember when you point a finger at someone there are three other fingers pointing back at you. I definitely see some zealotry in your posts. Is your head exploding?
      Listen, you didn’t like it, okay, others do. This country is supposed to be the land of choice. No one using a car tire on their motorcycle is harming you in any way so why all the vitriol? As far as anyone has been able to tell, no one has yet been harmed by the use of a car tire on a motorcycle. Fact: there are many far more dangerous practices than using a car tire on a motorcycle.
      The bigots of the world frustrate me. I’m going to get on my car tire equipped gl1800 and go for a ride. See you on the road.

      • Sorry, I refuse to let up on the C/T thing because you guys promote this stupidity on and on until someone is killed because he made the wrong choice. Explain your argument to those he left behind…..

        • I would be overwhelmed by your compassion for motorcyclists and your quest to save the lives of so many that might be killed running car tires if only it were not so much hogwash. There are many things killing motorcyclists today but you can believe me when I tell you it is not car tires. If you’re really so concerned about your fellow riders why not campaign against those things that are killing motorcyclists? Why not campaign for mandatory rider education prior to getting a motorcycle license as Oregon and a few other states have done? Why not campaign for driver education so they might stop turning left in front of us or pulling out into our path of travel? Why not campaign for more rider education classes to teach riders how to brake, swerve and turn so they don’t crash trying to stop quickly or while attempting to avoid an obstacle? Why not campaign for motorcycle tires that don’t delaminate, split or fail while trying to put up with the stress of hauling an overloaded GL1800 down the highway with a trailer in tow? Why not campaign for safer guardrails and road barriers so motorcyclists don’t die when they run into them? Why not campaign for making ABS standard on every motorcycle sold in America? Why not campaign for stricter enforcement of distracted driver laws to help get the cell phone users and texters out from behind the wheel? These things, my friend, are killing multiple motorcyclists every single day and you are concerned about the one that hasn’t happened yet, and may never happen? Really?
          I certainly do have compassion for those “left behind”; I am a paramedic with over thirty years on the job. There is a good chance I have spoken to more of those “left behind ” than you have. I am also a rider course instructor. I try to do my bit to save lives by teaching riders how to stop, turn and swerve. I attempt to pass on these street survival skills to my students in an effort to keep them safe. Yes, I ride with a CT on the rear of my bike, that is my choice but I neither encourage nor discourage the practice to my students. If I sincerely thought it was unsafe I wouldn’t do it.
          You may certainly call the use of a motorcycle tire on the rear of a motorcycle ‘stupid’ as this is a country with free speech but saying it doesn’t make it so. You may call it dangerous but that is just patently untrue. You cannot make a logical argument that the practice has been proven unsafe. One could possibly argue that there is not enough statistical information to prove that the practice is statistically “safe” but I could just as effectively argue that the practice has so far not been proven to be statistically “unsafe” either. If you are really trying to prevent motorcycle deaths and want to spare those that are “left behind” from the real grief that comes from losing a loved one in a motorcycle crash, as I have, then focus your efforts where it might actually do some good. Until then you are just another sensationalist rabble-rouser shouting about a cause because it serves your ego. That’s fine, you go ahead. Remember the free speech thing? Just don’t try to paint your self as holier than thou with concern for all your brother and sister motorcyclists because it is not a suit that you could wear well.
          By the way, I’m teaching a class next month, if you would like to attend let me know and I will send you the information.

        • Hey Look Mad Meteor my bottom line here is…do what ever you want…put a wheelbarrow tire on if you like…that’s up to you…but when it comes to promoting the use of car tires for others you C/T zealots should keep your foolish and possibly dangerous opinions to yourself. Personally I hope the DOT does a thorough investigation into this stupidity and starts restricting the use of tires not designed for motorcycles.

          • You just said “do whatever you want …put a wheelbarrow tire on it if you like…that’s up to you” Then you state that you hope the DOT gets involved and restricts……. So you really don’t mean the first 3 lines you wrote, correct? My choice or the Government gets involved? Let other people have an opinion. Everyone does not have to agree with you. I can say “run what you want” and mean it. I may not do it, but lots of room for others to do as they please.

  23. Hello fellow riders. I have read all the pros and cons of this topic. For two years now and about 22000km I have rode darkside on my Vulcan 2000 I would not go back to mc tire Handles just as well stops better feels much better in rain. And I pull a trailer as well. I say don’t knock it unless you have tried it. Mike Victoria bc

  24. Interesting article but I have to call “B.S.” Nothing but opinion from someone who has no experience or test results to validate his point of view. I want a real world test with large, heavy cruisers. With 2 up. With 8000 miles on the tires. Riding in flat, no curves Florida in 95 degree temps and a sudden downpour. Riding down my loose gravel driveway. I run darkside, just came back from riding Deals Gap and found NO negative effects. I did find out my lean angle was greater than a dresser Harley and much faster even though the Harley had MC tires!
    I have a Victory Vision, ride 2 up alot, pull a trailer (not at Deals Gap).
    Please provide REAL WORLD test. (I know it will not handle like a Ducati but geez I can only lean over about 30 degrees)

  25. The world is run by lawyers. No tire co. motorcycle co., or engineer can come out and say it is safe to run a c/t on a bike without the risk of being sued by some other lawyer representing a greedy accident victim.

  26. When I purchased my Honda 1300S, it was already outside of dealer specifications: wheels changed from spokes to rims, risers added, a windshield added, lowers added, fuel pump removed (the same Honda engineers who figured out the tire needs had forgotten about gravity, the 2003 was the only year they had a pump on a VTX 1300), pair valve blocked off to prevent backfiring, carb needle “shimmed” to get better horsepower and fuel efficiency (I now get 43 MPH), and it had a Brazilian VW car tire mounted on the back. It rode very well, handled well, and I loved the ride.

    A few months later I wrecked the bike when rear braking too hard on a hot road with “tar snakes”. I do not blame the tire, I blame my skill level. But at that time, I decided to have the rear car tire replaced with a motorcycle tire. My first ride around the block, the bike just dropped into turns unlike it had done ever before while I rode it. I liked it better, maybe as a fairly new returning rider, and have stayed with it. And I have stayed within dealer specs on the new tires, they are not manufacturer recomended Dunlops.

    Never did the insurance companies question the make or model of my tires in the cause of the accident, only checked the state of the tires, and verified that they were DOT approved.

    I have three rear rims in my garage now for the VTX: the one mounted with a Contienental Milestone motorcycle tire, and one to be mounted with a cat tire, and a wider one to me mounted with another motorcycle tire. I plan to ride the car tire on daily commutes, the stock size motorcycle tire on twisty rides, and the wider motorcycle tire on longer tours like the 1700+ miles I just complted, to help compensate for a larger load.

    To the manufacturer’s comments, no aftermarket part affecting performance should ever be sold. We all know that this is not going to happen, and each part that comes out has a group who adopt and test the results to a community. They are going to be more one sided because that is human nature, as are the manufacturers and scientists for the same reason.

    Until someone does a true scientific comparison across multiple motorcycles with multiple car tires under multiple riding conditions, we will never truely know the truth about “Darksiding.”

  27. This was a total waste of my life to read.. Poorly written, totally biased and gave no real factual data. All you did was interview tire manufactures, motorcycle companies and so called safety “Experts”.. yeah, none of them are going to stick their necks out to endorse Car tires on motorcycles.

    I have over 30,000 miles Riding The Darkside.. (on one tire) I ride a 1999 Suzuki Intruder 1500 LC.. BIG bike.. and Im a big rider.. I have had my bike on every type of road condition except snow and ice. I have ridden the Tail of The Dragon more than 6 times and several other of the most technically challenging roads in the country. Not once did I feel uncomfortable about pushing the limits of the bike. She has been floorboard to floorboard and not a single issue..

    If you want to discuss factual information then fine.. go get some, don’t write an article based on opinion.. Lets get some true scientific data to discuss. The write an objective, non-biased, fact based article.

    Darkside tire: $98
    Mounting: $40
    Mileage so far: 32,244 mile.. with tread left for about 3,000 more..

    “You don’t know the power of The Darkside!”

  28. Experts built the Space Shuttle Columbia, Experts build the Twin Towers, Experts built the Titanic….Sorry…all the above experts did something wrong….Again…stop the opinions..Lets pick on one…IF so many people are buying Kumho tires to be placed on motorcycles….the question you should have asked was “Why is Kumho not performing official tests of their tire on Motorcycles…why are you passing up an opportunity to make good money and expand your industry?”….that would have given the real answer…..Again all your experts in the article could not provide any evidence that the tire is unsafe….

  29. The practice of running car tires on motorcycles has been well documented in the past. I ran a car tire on my VL1500 Suzuki with great results for comfort and even rode it hard through some corners with great traction and no hint of trouble. Perhaps you could use some real journalistic practices and do an UN-biased article with conversations from both sides and dare I say some tests? If you dare…

  30. I have never been so disappointed by an article as I was this one. Frankly, it is not up to the standards I had expected from Rider.

    I have never used a CT on a bike, but have considered it and was interested in what I thought would be a thoughtful article, but instead found a rehash of opinions that appeared designed to please your advertisers rather than provide solid information for your readers. There are many other comments on the deficiencies of the articles and I agree with most of them. You should have done better than just present again all the old information and opinions.

    The reason I am interested is because I have seen a lot of sidecar drivers using CTs. If you think about it, having a round profile on the rear tire of a sidecar rig really does not make sense. A flatter profile, like in a car tire, provides much longer life and traction for a sidecar. I have had three sidecar rigs, and every one of them wore out the back tire in 4000 or less miles. This is ridiculous and why so may sidecar hacks sport CTs. The MC tires start to look more and more like CTs the longer you ride them. They just keep getting flatter and flatter, until the fabric is showing in the center. So why not just put on a flat CT in the first place?

    Most of the arguments that you presented just do not apply to sidecars and do not appear to be backed up by facts. Drawings are not facts. Neither are opinions. Reconsider this and try to do better next time.

  31. I think this article should be a ‘wake up’ call to the MC tire manufacturers. The MC tires are way way overpriced than regular car tires. Plus, they aren’t even that long lasting as they are priced.

    It’s similar to buying a gps for MC that costs a lot than a gps for cars, the only main difference, the MC’s gps are weather-proof.

    The car tires are more stronger and long lasting than their MC counterparts.

    Will anyone buy car tires if they cost more than a couple of hundred (US) dollars EACH and can (maybe) last anywhere between 4500 – 10,000 miles only.

    The scientific breakthroughs in making of car tires have been very cutting edge than compared to mc tires (not wanting to start a huge debate here).

    On an average, my car tires have lasted around 6 years &/or 50,000 miles. Depending upon their rebate offers, I always purchase my car tires (reasonably priced) at Costco or BJ’s.

    But, my motorcycle tires lasts only around 8,000 (500-700+- miles) miles & have to purchase & replace them at the motorcycle dealer at a higher cost compared to my car tires. No I am not a rash rider who’s trying to kill himself out there by doing stunt riding.

    Lastly, was this story funded by the MC tire companies?


  32. Wow,

    What a great debate.

    I’m considering the Car tire on my Valkyrie.

    I bet I will like it, or I won’t. 🙂


  33. After careful consideration, I chose the darkside about 25,00 miles ago. I ran a Kumho RF on my 2009 GL18 for 15K+ miles and replaced it with a Michelin PA3 ZP for the start of the season in April this year. The Kumho still had about 3k miles left in it. We ride 2up in the twisties frequently pulling a trailer. No issues with these tires on this bike.
    I’m not proselytizing – check forums for real info if interested. If not interested – that’s OK by me…

    It’s a shock to the status-quo and our view of order in the world when people begin to discover the earth isn’t flat; the sun doesn’t revolve around the earth; and viruses and bacteria are the cause of disease notwithstanding what the “experts” opinion might be.

  34. I appreciate the dialog concerning a car tire vs a motorcycle tire. Approaching my 3rd tire with only 17K miles, I have a 2010 Kawasaki Voyager. I had to do somelthing economical, thus I tried the General Tire Altimax 205-60-16.

    The downside has been the same others are experiencing: wiggle while navigating the grooves in the road. I had the same issue with a MT.

    The positive side: my bike’s speedometer is finally within a 1 mph variance, whereas with the MT it was up to 3 mph variance.

    I have only put 300 miles on the car tire, I usually average 1000 miles a month so I will know quickly whether my decision is a respectable one.

    So far I am happy, and if I get 20K out of this tire, I will be estatic.

    It would be nice to have a reputable company test the car tire side by side with a motorcycle tire. I am very interested in valid safety issues. Most car tire testimonies seem positive.

  35. Seems everyone here promoting the greatness of car tires on the rear seems to ride cruisers (big ones at that)… which IMO gives me the impression that they ride mainly freeways, for long stretches, rarely turning throughout their life. Fine… I can see a car tire working very well in such a situation…

    I, so far, haven’t read a comment from anyone in the crotchrocket, sportbike, dualsport, enduro, adventure, standard or dirt riding subgenres of motorcycling. Wonder why this could be….

    I ride a 2010 KLR650. From bikes in the past and including the KLR, when the MC rear tire starts to wear flat across the bottom of the tread, leaning into a turn (any turn where the lean is over 15 degrees) produces produces a definate shimmy as you rise up from the flat onto the edge… that really annoys me. Would I put a car tire on my bike, hell no! I enjoy the ability to ride the twisties with no compromise.

    I have come to three conclusions in reading this opinion/article and it’s comments:

    1) Got a big cruiser and lots of freeway riding? A car tire could be something to look into!

    2) Dunlop tires are crap!!! (experience talking)

    3) People who shell out big bucks $$$ (over twenty grand) for a nice cruiser with all the bells and whistles sure like to nitpick the minor cost of a tire…

    • I do turn, and turn hard within the limits of my heavy cruiser. My Vulcan 2000 sharpens floorboards at pitiful lean angles, but I make up for it with full throttle rollons out of corners – My car tire (General Altimax HP) hasn’t even come close to its traction limits.

      Also, I’ve rarely heard of any Harleys running car tires, the rest of the cruisers are metric ones that aren’t anywhere near 20 grand.

      Yeah, this isn’t for sportbike riders, although I have heard of Yamaha FJR1300s mounting car tires and liking it. Inherently, a motorcycle tire will have better traction at high lean angles (such as with a sportbike) than a car tire, but at moderate lean angles, such as cruisers, in my firsthand experience the right car tire on the right bike has better traction.

    • Ryan,
      No one ever said that c/ts are good for sportbikes,or crotchrockets !
      Just the opposite. Cruisers,and touring bikes can use them,because of the different way they are ridden.
      Spotbike/crotchrocket riders are much more aggressive in riding(and , sometimes downright dangerous),whereas the cruisers,and touring riders,enjoy a leisurely ride,while still getting into a few twisties,occasionally.
      One thing not mentioned here,that many Darksiders(as well as OEM riders) do,is use Dynabeads for tire balancing,instead of the tape-on,or snap on external balancing weights.
      Dynabeads are a far superior way of balancing tires. NOT just on MC’s,either!
      Most tires made for the heavier cruisers,and touring bikes,are NOT safe,even as OEM ! Case in point: My 1984 GL1200 Interstate.
      Curb wt=748lbs. Gross weight=1080.lbs. That means if I weigh 208 lbs,and my rider is 160 lbs,and the hlmets,and jackets/chaps/boots add 100lbs, then the vehicle is already overloaded,without putting anything in the trunk/bags/trailer !
      To make it worse,the OEM tires are Dunlops,and are not rated for more than 987lbs ! The best MC tire for my Goldwing,is only rated at 990lbs,and ONLY 70 mph ! Cost for a pair=$400 + !
      So,TELL ME, AGAIN, how the tire mfgrs are making them safer than a C/T that has a safer load rating/better mileage ,and in most cases better handling .
      The mc manufacturers will continue to put on the cheapest tires they can,to make better profits,and the tire makers will continue to make the tires wear faster,to make $$$,more often.

    • I’ll have ridden 21,000 motorcycle miles before the end of this year (2014). I have well over 20,000 now.

      At a minimum of 150/rear tire and 60 dollars installation, we are not talking a pittance when we consider replace that rear possibly 3+ times in one year. Now if I was ONLY riding 5000 – 6000 mile annually and only replacing that rear tire once a year I wouldn’t worry about it BUT since I am …

    • I have seen sport-tourers running car tires. I rode with one this past summer…a long riding day through the Berkshires and southern Vermont…he had a car tire on the back of a Honda ST1300, and was riding 2-up with his son.

      Wow. I was dragging my muffler and center stand, and he was pulling away. He took a tight double-S-curve going at least 50MPH, with no trouble…I took it slower (40-ish), and was dragging parts.

  36. You are free to run what you want. We all have our own unique experiences and economic situations that lead us to the choices we make. I am not going to be able to convince car-tire-proponents that they’re “wrong”, because of their personal experiences. If it works for you, do it…all this crowing on about “I’m right because I use one and like it” is meaningless. I’m not “wrong” because I choose to use, and happily pay for, a motorcycle-specific tire. I probably have less $$ to work with than a lot of folks. If some want to cheap-out and put a car tire on their machine, why do you care what others think? It’s your bike and your money, you are free to spend it on whatever you desire.
    Personally, after experiencing a ride on a VTX, V-Rod, Road King, GL1500 & GL1800 with a darksiders-forum recommended car tire on the rear, I would never do it on any of my bikes. My choice…it’s your bike, put a tractor tire on it if you want. I do get tired of people complaining about prices. Prices are the result of, and about, economy-of-scale, not some insidious manufacturer or a ridiculous conspiracy-theory out to personally wallet-rape you. If you’re interested in that scenario, all you have to do is work behind the counter (like I did for 20 years) at a brick & mortar old school stereo/audio store and see what speaker manufacturers get away with. When you only sell for example, tens of thousands of something, compared to a few millions of something,. it’s going to COST MORE to make and to buy. Motorcycling is small compared to the auto industry and it will always be this way. Motorcycle things are more expensive; parts, gear, service and TIRES. The old saying “you knew the job was dangerous when you took it” applies here. Sure you can economize when appropriate. I look for sales and good deals like most. One thing I will not compromise on is my ability to effectively control my bike and protect myself from oblivious car drivers, and not add to decreasing that ability. Which means I maintain my bike in top condition; that requires a bit more expensive oil and other consumables. My tires are my only connection to the tarmac and the only way to know what’s going on at the contact patch. Talk to Dave Searle at MCN about this issue, being able to have a decent lean-angle on your bike so you can swerve (lean over farther) if you encounter an obstacle or someone in your lane going around a corner. Sorry, but 25 or 28 degrees of lean-angle isn’t enough, like some of the Sportsters and FL chassis bikes I’ve ridden. I’m not referring to just sport bikes, either, as even riding at a moderate pace with some bikes uses up all the available lean-angle when cornering. For those that still believe the fallacy that advertisers dictate the editorial content, Mr. Searle doesn’t have to be concerned with advertisers, like some people have suggested that advertising influences moto-journalists and their writings. And the people that have asked “have you actually used a car tire or ridden a bike that has one?”, I will point out to you: has anyone who posted in this topic ever been a motorcycling journalist? Have you ever spent any time talking with or riding with them? This notion of “they won’t bite the hand that feeds them” is BS and could only come from a place of ignorance with those who have never been “behind the counter” at a motorcycle magazine. I’ve interacted with guys like Fred Rau, Don Canet, Mitch Boehm, John Burns, etc. Mainly because my unique situation as an oxy-moronic “handicapped” rider with an insidious degenerative joint disability, SEDT. Meaning I’ve endured a tremendous amount of challenges to become and remain an accomplished motorcyclist, and they were interested in my situation and what I’ve gone through. They do not kiss advertisers asses, nor are their opinions shaped or influenced by who or what is paying for pages in their respective mags. If you don’t believe me, have a talk with Clement Salvadori and tell him his writings and opinions are shaped by who’s paying for advertising. You guys don’t know what you’re talking about with that particular issue. Until you’ve been on the masthead of a motorcycle magazine, let’s dispense with that drivel. I could tell you things I saw concerning the popular, recognized speaker OEM’s that would cause you to never buy a recognized big-box-audio-store speaker brand again. The amount of lies and hyperbole is unbelievable. And the build-quality (cabinet construction) is poor because you never see the inside or have been able to aurally compare to something that has a substantial, braced cabinet and has a properly designed crossover. They’re sold based on aesthetics, marketing-speak, and much techno yak-yak, not how well the enclosure is constructed or how well the crossover was developed and implemented. What you end up with at your home has been compromised severely by bean-counters who strangle the designers & engineers who actually want to make something that sounds better. You don’t know it can be better because all you get to listen to and compare with is other compromised retail offerings.
    The car-tire guys, keep using your car tires. But after being able to ride those cruisers and two different Gold Wings with car tires, I will not be doing it. And I won’t ride with or next to anyone that runs a car tire after seeing how those bikes handled and how the individual pilots operated/controlled those motorcycles. Thanks for the opportunity to speak about my concerns. Just keep riding, that’s what it’s all about.

    John A.

    • One other thing about credibility: David Hough has more of that in his little finger concerning this topic than any car-tire-proponents have in their whole being. Eric included David in this discussion because his words and experiences carry the credibility that is needed. That’s all I need. I had a chance to meet with and talk to Mr. Hough at a Seattle motorcycle function. His knowledge, experience and mileage on many different bikes including sidecars/trikes should have meaning here…something the CT guys conveniently overlooked. If you don’t believe or listen to David Hough, you’re beyond help, reason and common sense. Have fun saving some money. Put some loud pipes on your bike and subscribe to the other fallacy that “loud pipes save lives” to complete the lunacy. Thanks Rider, I won’t be childishly canceling my subscription because I don’t agree with something.

      John A.

  37. I have been running a General UHP Exclaim 205/50/17 on my DL1000 Vstrom for the last 500 miles.
    I like it!
    Is it for everyone, NO!
    I have slowed down in the twisties a little, but that has made my riding buddies happy.
    Iam only shooting them at 10-20 over the speed limit now!
    I have had one case of head shake but that was after passing a vehicle at around 80-85 and some wise ass put a rumble strip at the center line of the lanes.
    I have 2 Vstroms, the 650 and 1000 and the tires are definitely different to run from motorcycle tires.
    But depending on the riding application I find it no big deal.
    My 650 has 80/20 adventure type tires and my 1000 I have built for 1000 mile days.
    The Darkside will be my Alaska setup and thats what I have been testing it out for to see if its workable before setting out on a 3 week trip and decide this is not working.
    You will not find a magazine or company that will tell you it works and except that liability period!

    • I just crashed my Ural but have bought a Suzuki 1000 vstrom to replace it .I am looking for a suitable car tyre to use on the rear drive on the bike & keep the bike front tyre & sidecar tyre at 19″.I have met an elderly gent that only uses spacesaver tyres to do same without a problem .This is not my idea of a good way to go.All I want is a tyre that will handle semi off road conditions & get good miealage with speeds rarely exceeding 70mph.

      • some spacesaver tires have a round profile like motorcycle tires. I’ve no idea as to how good they are , but at $10 (including a wheel) from a salvage yard they certainly are cheap.

  38. I’m not sure what the “tire patch” issue is about. I have seen videos where a rider has mounted a camera under their motorcycle and when they corner, the “tire patch” is greater on the auto tire than on the motorcycle tire. While I understand the differences in construction, if the amount of rubber on the ground isn’t important, then why not use thinner tires for better mileage with less rolling resistance? The video shows at least 2″ more contact area with the car tire, and while the motorcycle tire is shaped differently, even a car tire mounted on a car will roll to the side going around a sharp, fast curve. While I don’t claim to understand this argument totally, it seems that by talking to only motorcycle tire people, you are weighing the odds in favor of them, and the sale of their tires. Of course it will handle differently, different brands of motorcycle tires handle differently, duh….. And while some of us like a “spirited” ride through the corners, most luxury bikes spend their lives on the super slab, not the dragon….

  39. This video is much like what I saw riding behind an FJR on a curvy road. The CT didn’t slow down the other FJR and I didn’t see any problem regarding the tire holding a line or doing weird things in the corners.


    Most people who respond on this list don’t give any personal information regarding their riding skill, longevity, level of experience or how many miles they ride, so when people post without some notes to their credibility, most every thing said must be taken with a grain of salt. Those riders that log over 30,000 miles a year may just command a little more respect than those that only ride 7,000 miles. Those that use a CT are different people, with different objectives but not necessarily any less concerned about their lives, or their passengers life, or even the expense of the tire. To assume either of these points is only a distraction and a waste reading time.

    With only 300K under my belt and only doing 20K to 25K a year, I do get tired of changing tires. I am on my third rear tire this year, which is my usual for a year. I would like a tire that would last 30K and be designed for a motorcycle, even if it was only recommended for freeway. Many of the long distance riders do most of their miles on the freeway, but do venture off for a good twisty section too. The market for long distance tires would be bigger if the Manufactures produced such a tire, but until then you will find people trying to make this work with car tires. I commend them for doing so and making the statement in a positive way. Now it is up to the motorcycle tire manufacturers to take note and do the right thing.

    It is also time for the Magazines to also provide respectable articles on this subject too. At least mount up a CT and test it. We all know you aren’t going to do this to a sportbike.

  40. One of the biggest issues facing the argument is that engineers do what has historically worked and often miss the obvious because of it. As an operating engineer on a destroyer, I found a useless valve submerged in a fresh water tank. What was the valve attached to? A salt water line. The result was continually salting a 1200psi boiler. To put that in the words of Igon from Ghostbusters, that “would be bad.” When reported to SupShip, they maintained that it had to stay the way it was designed. Since they weren’t the ones that would go before a Courts Martial if the 1200psi system failed and killed a sailor, I had it changed. No more salting problems. Put a run flat car tire on your motorcycle and be safe. Let the pencil pushers believe they know it all.

  41. I rode car tire on my BMW sidecar rig with a modified wheel. Rode great. However, I’m on my way to see a friend in ICU who was seriously injured when a car tire blew up when attempting to mount a car tire on a motorcycle rim. See Hillsboro Times Gazette for9/22/12

  42. I own a 2007 victory jackpot. After only 6,000 miles on my current rear 250 tyre, I find that it is already significantly worn. My next tyre will be a 255/40/18 car tyre. I accept the judgements of those who have tried and succeeded. I congratulate you all.

  43. Let’s be honest… This really boils down to one thing and one thing only. People that are putting car tires on their motorcycle are doing it because it is cheaper. The tire manufacturers are telling you that you shouldn’t do it…the motorcycle manufacturers are telling you not to do it, and if you asked your average biker they would say “why the hell would you want to do that” . people putting car tires on their bike are cheap. a motorcycle tire is meant to be round not square end of story.

    • Lots of comments here about cost. I “Darkside” and my last thought in reference to bike tires is about cost. If bike tires cost half the price of a Michelin Alpin Z (run flat) I would still use the Michelin. Not trying to convert anyone, just my opinion.

    • No matter how many times you (and others) regurgitate that, it is still wrong! The darksiders I know do it for one single reason: because they ride 2-up on big touring bikes, and have had multiple MC tires fail due to not being able to handle the weight!

  44. “Dare I suggest that it’s not unlike the way brain surgery calls for a specialist in neurology. Would you turn to a gastroenterologist for that procedure because he or she has a lower hourly rate than a neurosurgeon?”

    Only if I had my head up my ass.

  45. I put a car tire on the rear of my 05 Venture, and a rear motorcycle tire up front. I have 23K on the rear tire, without any problems. The only difference I found in handling is that it can get a little squirrely on uneven surfaces. Not a big deal, and I have never had a problem. I took the bike to the twisty roads of the Ozarks, and rode with a bunch of people on sport bikes. I had no problem keeping up with them and I passed a couple of them. The bike seem to grip much better in the curves than the motorcycle tire I had on before that. I suspect I will be putting a new tire on it this spring, but it’s still in good shape. I figure 25k or about that is good enough for the CT. I take a lot of long rides and want to make sure that it will hold up for 4k to 8k. Another concern I have with motorcycle tires is that if I am going to do an 8k ride, I need confidence in my rear tire. I would think I would have to get a new tire installed with the motorcycle tire after 6k. On the road that could be a problem. Not a problem with a car tire.

  46. Hi i want to fit a 15 inch car tyre to my xv 1100 virago sidecar outfit as bike tyres wear out very quickly i have tried to fit one but it will just not pop up onto the last bit of bead even with plenty of lubricant &90 plus pounds of air pressure To confuse the issue even more i previously had a michelin car tyre on this same rim & that fitted ok ?? Any ideas anyone as i am reluctant to buy more new car tyres that wont fit thanks john


  48. As to credibility, I just wonder how much experience with a car tire on a motorcycle Mr. David Hough has. Possibly as much as could fit on the head of a pin?….. but that is just a guess though I think you see my point with that.

    About the whole kerfuffle about contact patch: The size of the contact patch per laws of physics is that it is a function of weight bearing down on the tire and the tire pressure to cause equal distribution of that weight. This; regardless of contact shape. If the weight bearing down on a tire is 300# and there is 30 PSI in that tire, then the contact area will be 10 square inches regardless of the shape it has or what kind of tire it is. Period. If the tire pressure is higher, then there is a smaller contact patch. Lower pressure would mean a larger contact patch. Of course there are practical limits to this for reasonable usability.

    what is important is the coefficient of friction. That is; how well it grips. Almost universally, motorcycle tire rubber compound is harder than car tire rubber except maybe in some specialized applications. I would venture then that softer rubber is better able to conform to irregularities in the road surface at microscopic levels providing a better grip. That is a logical assumption, but it would need serious testing to prove with absolute certainty.

    Car tires have higher load ratings than MC tires and cars put far greater lateral loads on their tires in turns than a motorcycle would ever be capable of. On a motorcycle, nearly all load is directed downward to the tread and seldom to across the width of the tread. So the sidewall would not likely ever get over stressed either.

    Bike riders regardless of their riding style, spend most of the time and miles riding in a vertical position so tread wears the center of the tire first. Consequently, there is unused tread uselessly remaining on a MC tire when a tire change is needed because of that center tread wear. That may be part of the reason for car tire longevity where most of the time the whole tread face is used to distribute load and wear and on a MC it is just wearing the center part of the tread. With a car tire, the tread area flexes so that in a turn, tread touching the road is parallel and in contact with the road while the rest is not; just as it would be with a MC tire.

    All of this and more from the guy who originated the use of a car tire on the 250cc Honda Reflex scooter and currently has 35,000 safe, trouble free miles on his 145/70R12 car tire on the rear and 17,000 miles from use of a Honda Silverwing scooter tire mounted up front. Both with many, many more miles of tread remaining.

    • “With a car tire, the tread area flexes so that in a turn, tread touching the road is parallel and in contact with the road while the rest is not; just as it would be with a MC tire.”

      I followed a GL1800 with a car tire across West Virginia and observed that the tread does not stay flat on the pavement when the bike leans. Only the edge of the tread was on the pavement so the contact patch was clearly smaller than a rounded motorcycle tire. This rider used low air pressure in his tire – the sidewalls flexed and squirmed like crazy – but beyond a certain lean angle the flat of the tire lifted off the ground.

      You talk about “regardless of contact shape” but a car tire’s edge is 90 degrees and the rubber is stiff enough to not flatten out when leaned over.

      All of the car tires that I have seen on motorcycles have rounded edges proving that they are riding on a narrow edge and that round is the natural shape for a bike tire. No, I am not going to try a car tire. What I observed scared me too much. I like to lean.

  49. I needed a tire that would give me at least 10K miles, loaded for a multi-month trip, two-up to Central America on my DL650. At the time, the ME880 was about the best mileage tire and even that wouldn’t do. I decided to try a CT even though I was very skeptical especially since I like to scoot along pretty fast in the corvers. At first, I was a bit disappointed as it was pure hell to mount but eventually with the help of a ratchet strap, I got it mounted. I can tell you this, with that CT on that rim,,,, there is no worry of some BS catastrophic bead flying off.

    Once I got it on, more disappointment. I was brow beaten by the internet Chicken Littles of the world into thinking those beads would pop off at the slightest provocation and I aired it up to the max pressure which was something like 45psi. Terrible,,,, I live on a 1/4 dirt road and immediately noticed that the tire width accentuated every bump, rock and rut. Got to the end of the dirt road and lower the pressure to 40psi. Road about 15-20 miles and while better, still hated it. I then lowered the pressure to 30psi and low and behold,,,, it’s started getting better. At this point I was on my beloved “Loop” which in N. Ga. is Hwy 60 to Hwy19, then Hwy129, then Hwy180 and finally back to Hwy60 and in between, quite a bit of rough dirt roads for some off tarmac testing.

    I lowered the pressure to 20 and then hit some dirt road mileage. Better but then I lowered it to 15 and found that too low even on the dirt. While the CT’s manners were much improved, I still don’t like it as much as my normal Shinko 705s or TKCs or Big Blocks. But,,,, I hit the tarma again and aired back up to around 25psi and honestly,,,, I was very surprised. Yes, the CT slows the steering input down a bit and it takes a smidge more muscle than a 705 but anyone that has ridden a DL with 705s knows the front 705 is a very quick and light steering front so the CT on the rear actually results in a more “normal” feel.

    My DL is heavily modded with DR front forks and a custom rear shock, I’ve raised the bike around 1.5-2 inches and has a couple inches more travel than OE. The front forks have a set of modded Intimidators and stiffer springs. The rear shock has about an inch more travel and is stiffer than OE as well. In all honesty, this DL is worlds better than the stock DL. I use the bike hard in the corners and when it was stock, I could easily drag the pegs in pretty much any corner from a tight 20mph hair pin to a 90mph sweeper. With the added couple of inches of height, dragging the pegs is no longer an issue but I still tick em down from time to time. I added this to help illustrate how this bike is used. It’s not a DL that you see diddling along holding up RVs,,,,, more often it’s railing along trying to play with the squids on their Gixxers then peeling off on some rocky, rutted rarely maintained dirt road to play adv rider with KTM Adventures.

    With that said,,,, after a bit of a learning period and gaining some confidence, I will say without hesitation that I love the CT on this bike in this application.

    Fact,,,,, all motorcycle tires force compromise. If you want mileage, you are forced to deal with low traction and often,,, less than stellar handling. The ME880 suck in the twisties and on dirt and I hated it in the rain.

    If you want a tire that will handle and stick well while you are playing make believe Rossi with the squids,,,, well you are lucky if it lasts longer than 3K miles and it too suck in the dirt.

    My favorite tire for this bike are the Shinko 705s and I often run a TKC or a Big Block front with a 705 rear for playing around locally. Still enough traction to have fun in the corners yet works “OK” in the dirt and will last around 5K miles when playing locally.

    For touring I run 705s front and back and combined with high air pressures and a soft touch on the throttle will return around 8-9K miles.

    Welp, my CT experiment went over 13K miles while playing and commuting locally which is at least double of a 705 used in the same manner. Matter of fact, I was exceptionally hard that tire and wore a brand new, installed at the same RK chain which normally, will last over 20K miles! In other words, if this CT were used in a purely touring application, I have no doubt it would have lasted at least 15-20K miles which is what a front 705 is good for if ridden conservatively.

    This is no bull, the CT gives BETTER traction than the tire I normally run, the 705. It gives better traction while straight up, braking, accelerating. It even gives BETTER traction while heeled over, draggin a peg and accelerating outta tight curve. While it doesn’t “handle” as well as even a 705 when really hauling the mail, it does give better traction. Read that again, better traction while heeled over. My bike, being better suspended and being a couple inches taller has much higher limits before dragging the pegs than a stock DL so do try to convince me that a CT is more dangerous “if all of a sudden, one has to make hard steering correction in an avoidance maneuver”. It also give better traction in slick conditions like in the rain or the snow {yes,,, I ride in the snow on the few occasions we see it}.

    In the dirt, the CT actually gives good traction on regular packed dirt roads. Better than even the 705s, maybe better than TKCs or Big Blocks. But, when the going gets muddy the CT sucks. When it’s sandy, not too good either but better than the 705 I think. When it gets really rough on rarely maintained dirt roads {thing Jeep/4×4 trails}, every big rock and rut upsets the bike because of that huge CT’s width. Not as bad when the going gets faster but at the very slow speeds where a bike like this would be on roads like that, it can get aggravating, especially at 1st during the learning curve. I learned to ignore that after awhile.

    The bad,,,,, well, there are a few draw backs JUST LIKE ANY OTHER TIRE CHOICE. First off, there is that rough dirt road handling. Most street bikes and even most DLs don’t go off road in places like that so to most, that’s not a biggie.

    The CT weighs alot. Tires that weigh alot just don’t handle as well due to the high unsprung weight. You really notice it in washboard dirt roads but you also notice it when really hauling the mail.

    That weight also effects acceleration. I thought the Big Block weighed alot but the CT alone probably weighs what most bike tires and wheel combos weigh. It will feel like you lost 5-10hp.

    But honestly folks,,,,, this is a DL650. It’s the SUV of the bike world and in that context, losing a smidge of acceleration, a smidge of handling at the very outer edges of what the bike itself is capable of both off road and on is more than a good trade off for more traction on road, most of the time off as well, longer life, like 2-3 times the life and overall durability {the CT will scoff at rocks and road debris that would damage a bike tire}.

    Would I mount a CT on a Gixxer and play Rossi? Nope.

    Would I mount a CT on a KTM Adv and do the Trans American Trail? Nope.

    Would I mount a CT on a Wing or a cruiser? Yep, in a minute.

    Will I run another CT on my DL or experiment with one on my FJR? Absolutely!!!!

  50. I ride with a group of rider that use car tires (together we have over 150,000 miles on car tires). There have been no failures and we frequently drag the footpegs in corners.

    After the group experienced 3 tread separations on MC tires I contacted the manufacturer to see if there was a problem. I was told the tires should not be used on a goldwing in extremely hot temps, should not be used if the bike is over weight (many goldwings are), and should never be used to pull a trailer (many use trailers even though they are not recommended by the motorcycle manufacturer).

    With a car tire I get better handling of the weight, it runs cooler, and has never displayed any problem with trailers.

    By the way If you price a few runflat car tires they cost as much as MC tires (although they do get about twice the mileage). Cost (at least with me) is not the issue, safety is the only issue.

    Since we have had several tread separations (3) with MC tires and absolutely no problems with car tires, I choose to run what I believe (from experience) to be the safest tires for the way I ride (frequently 2 up with a trailer).

    If they ever develop a MC tire that will actually function in the real world for goldwing riders I’d be glad to switch back.

    We all have our opinions and this is mine…


  51. Funny how all these “dorksiders” sing the praises of a square tire on the back but none of them would risk one on the front! What’s good for the goose should be good for the gander, right? The certain fact is, they’re unsafe at any end and at any speed, and on any motorcycle.

  52. Well fellers I am coming at this from another angle, I am riding a v~star 1100, but with a side car mounted at all times. We have one for around town & short trips & another larger car for touring , now as I am not using the muched aruged point that car tyres are not suitable for bikes because of contact surface being so different in cornering on a solo bike.

    But again today I have been to several bike stores trying to buy a rear tyre & at all these stores I have been urged to fit a normal morotcycle tyre.

    Now what the hell, we do not lean we are not riding a two wheeled machine we steer into a corner. Yet all these companies will not even consider a car tyre being fitted !

    My last tyre lasted ? 7000 k & the only section of the tyre that had any wear was approx 50 cm each side of the centre of the tyre outside that it still had the nipples attached ( no wear at all )

    So Rider ask your tyre manufacturing people what they think

  53. Makes me wonder if the author of this article ever looked through the owners manual of any motorcycle. If he had he would have clearly seen statements from the manufacturer about making modifications.
    I have seen this magazine promote all sorts of modifications like raking a front end, towing a trailer, aftermarket shocks all of which manufacturers have stated not to do. Clearly, the hypocritical statements made in the article were not on any of minds of the Riders staff.
    Technically aftermarket shocks would change the behavior and characteristics of the bike. So by this authors own logic should not be done.
    I inherited my cruiser from my father who had a car tire on it. Without even knowing the controversy have put over 15,000 trouble free miles on it.
    I am very saddened by the bigotry shown here by the author and by Rider. . My suggestion to Rider would be to first try something before making a final judgement on it.

  54. Rider Needs a New Writer – Nothing Stated came close to reality.

    One would think you were only on 50 degree lean BMW R1200 – or – R1 , vs limited lean Cruisers of 30 degrees.

    That’s the biggest pile of FUBAR ever read as certified Honda Dealer Tech the last 35 years.

  55. I think this article is pathetic. It is oh so similar to another that I read on the issue. It cites the opinions of experts on the practice of using a car tire as the rear tire of a heavy motorcycle as the final arbiter of the issue.

    We are talking about a resource to motorcycle riders. Motorcycle product reviewers whose JOB it is to investigate possibilities when it comes to motorcycle products and motorcycle practices. While the subject is NOT a motorcycle product, it IS a potential motorcycle practice.

    While it is true that the only folks championing the use of car tires as rear motorcycle tires ARE those who are doing it in a purely anecdotal way, that is the only information and resource available that offers ANY information on the subject of usage from an experiential perspective. The small amount I have read appears to be positive and in my mind, bears ALMOST as much weight as the reviewers regurgitations of the engineering experts that strongly discourage the idea. More research of anecdotal report reports that reveal no glaring safety reports will probably convince me give this idea a try.

    I know at least five folks personally who are doing this and none of them are speaking of a down side. They mention a few practical considerations, like a need to slightly over inflate you tire by 6 – 8 PSI.

    Why would I consider this?

    I just put new tires on the front and back of my 1999 Yamaha Royal Star Boulevard and with 5 thousand miles on them I realize that I’ll only get about 5 more thousand miles on the back tire. Wow, 10,000 sounds like a lot of miles. Ya think. I get maybe 30,000 on my car. It costs me about $100 to replace and installed. If I shop on the web for some bargain tire (like I did) and get a Shinko, maybe I can get it for about $100, then it will cost me at least $60 to have it installed. If I get a Dunlop, it will cost at least $150 if not more and I could pay up to $78 to have it installed.

    OK, when I replaced my tires in June, I did it myself. I figured I could save a LOT of money on the installation fee – but I had to BUY a few tools. So the first time cost a LOT more. I couldn’t buy the tire machine because it cost too much – but I probably will. I spent two entire days changing two tires. Doing it by hand with levers is a LOT of work and even though I tried to be careful I ended up having to replace two brake disks, so now my do it your self job got even more expensive.

    I figured that if could do the job myself and could get 15,000 miles on the rear tire I would be good. But now I see that the rear tire may only last about 6 months. That’s right, I put 16,000 miles on a motorcycle over the past 12 months.

    Considering the life expectancy folks are reporting for car tire usage as rear motorcycle tires we are not talking chicken feed here! We are talking about the difference between replacing the rear tire 2X a year as opposed to once every 2 years with a minimum of 1/4 the cost of rear motorcycle tires over a 2 year period. We are not talking about a few dollars difference. When the EXPERTS quit marginalizing this issue folks may START to give their advice more credence.

    Oh by the way, my front motorcycle tire WILL probably last 2 years!

    You folks are disgusting. You could do REAL research on this idea which would make your publication more valuable to your patrons, BUT it would cost money to do it, it would take time to do it AND the motorcycle tire industry would not pay you any money to do it.

  56. There are at least two locations on the internet where car tire users are collating data of usage. One is the ‘darkside’ on the GL1800 forum.

    The other is on the Delphi Forums Darksiding forum.

    The database is growing. There have been few documented cases of car tire failures (each appears to be extreme wear). There have been no accidents attributed to car tire use.

    I used car tires (actually small trailer tires) on my scooters in the fifties and early sixties (Cushman and Vespa). I put a car tire on a drag bike I built in the midsixties.

    Currently, on my new 2012 Goldwing, I picked up a big, ugly, screw in my rear tire. After reviewing the data, I replaced it with a Michelin Alpin PA3 ZP (run flat). It provides equal or superior cornering ability. It is noticeably better in stopping ability. It rides on gravel more sure footedly. My wife likes the more comfortable ride, which is the norm for passenger evaluations.

    I expect to get 20K miles out of the tire, even though I tend to be harder on tires than average. On my Valkyrie (owned it for 10 years), I tended to burn front and rear tires about every 5,000 miles. I’m a little more sedate on the Goldwing.

    But, with the run flat, I don’t expect to have an explosive decompression at speed. I have peace of mind, knowing that there isn’t a documented case of a car tire shredding like a bike tire does sometimes. And, with the run flat, I can ride for at least 50 miles at 50mph. That’s listed for a car. On the Wing, I might get twice as far. That can certainly be a trip saver when riding in the remote sections of the country.

    I’m so pleased with my car tire, that I will be ‘double darksiding’ when the front tire needs replacement. I will use a thicker treaded rear tire on the front. More tread equals greater safety! And longer tread life.

  57. Like a lot of magazine articles. No experience in the subject, just fluff!
    If you want useful information, you need to read the forums and get first hand knowledge good and bad.
    Magazines are best for the pictures, not information.

  58. For those who think the darkside is not for sportsbikes, think again. I don’t own a sportsbike, but while researching the idea for use on my cruiser, I ran into this:

    This guy is doing just FINE running a CT on his sportsbike. It corners as good as the best of them!

    Now I have put a CT on my 1999 Yamaha Royal Star Boulevard and just LOGGED 1000 miles. I don’t just ride down straight of ways on the free way. I like cruising the back roads better and the twisties are the BEST! I’ve leaned far enough to scrape my floor boards a couple of times. Once on an MT and once on my CT!

    Here are the truly notable design difference between a CT and an MT:
    – the beads are different so you may want to check your air pressure regularly. I check my tires daily by “kicking them”. Now laugh. After a month of riding on the CT (putting 1000 miles on them) they are still nice and hard. This weekend I’ll be the pressure gage out and top them up if necessary.

    – the side walls on a CT are not as rigid. You may notice a wobble when cornering. You correct this by putting another 6 – 8 PSI of air in your tire. I was told this by a Gold Wing owner who was darksiding. I started out with about 5PSI over. I noted that and called it good. I’ve NEVER noticed a wobble.

    – car tires are made of SOFTER rubber! Some folks think that CTs last better because the rubber is harder. Of course this would mean their traction is worse than a motorcycle tire. But it is NOT the case that CT rubber is harder. I asked a Car Tire Dealer, Budget Tire to be exact, the folks who mounted my CT on my motorcycle wheel! They said that CT rubber is softer that MT rubber AND winter tires are made of the softest rubber of all. So WHY do CTs used on motorcycle wheels last longer? Because they have a broad flat area that grips the road better (and softer rubber helps with that grip) providing less slip during acceleration and LESS LOSS OF RUBBER.

    – Oh, I forgot about the LEAN issue, i.e. camber thrust, one track vehicle steering. The factory spec for my tire size is 150/90-15 for the rear tire. For the front tire it is 150/80-16. The left most number is the width of the tire. The number on the right side of the “/” is the aspect ratio. It refers to the height of the tread above the start of the side wall as a percentage. The number to the right of the – is the radius of the wheel. For the car tire I used this sizing?: 165/80-15 for the rear tire. Note that the tire is 10 mili-meters wider so the difference in height between the top of the tire and the beginning of the side wall (the working part of the tire on the side) will be ABOUT THE SAME. Which SUGGESTS THAT THE AMOUNT OF LEAN YOU HAVE WILL BE ABOUT THE SAME! See the youtube video above.

    The only REAL difference in handling that I can tell was noted above by somebody who tried a CT and after a while went back to an MT. On the switch back he noted that he really had to go back to the MT to catch the way the bike just dropped into a lean on the MT!

    This is a no brainer folks! Look at the bottom of a CT and note how broad it is and how the edge quickly wraps around and heads to the side wall! But is this a huge issue? No! When I first started riding with a CT I BRIEFLY noted that it took a bit more effort to initiate a lean! It didn’t take but a couple of times out and now I am 100% used to it and totally do not think about it! It corners as good as it ever did! I love it. I spoke to a guy who had darksided for a number of years before discontinuing that practice. He made the same observation (and our friend above) made about the lean initiation issue. Why did he discontinue darksiding? Let’s ask a reciprocating question, why does anybody start darksiding? Because you are putting many thousand miles a year on your bike and do not want to replace the rear tire multiple times in one year! The guy that quit no longer had a need for that high mileage of a tire. He had several close calls in recent years due to car drivers pulling out in front of him and so he cut way back on his riding. At one time this guy told me he put 37,000 miles on his bike in one year. Me, I put a new tire on in June and placed it in September. I live in Michigan but ride all year.

    Darksiding is not for everybody. if you only put 5000 – 6000 on you bike a year you’ll probably be replacing the rear tire annually which is not too bad.

    CTs and cornering are NOT a big issue:

    When you replace a motorcycle tire you will always have to get used to the way the new tire handles whether it be the same brand or a different one. They are ALL different.

    The difference in cornering between a CT and an MT are not an issue. And the softer rubber of the CT enables it to get a better grip when cornering. If you understand and have mastered the concept of counter steering you can drop your bike into any lean you want.

    The folks who make MTs COULD make them to last longer by making them wider, and with a much broader working face and a fast shoulder drop off LIKE A CAR TIRE but with a bead and side wall made for a motorcycle BUT t hey are not going to do that! Why? Because most of these same companies make car tires TOO and they know that a small group of brave belligerent people will use CTs on their bikes but the rest will listen to the advice of EXPERTS (their marketing shills) and do the appropriate thing! I mean after all, if you only put 5000 miles on your bike annually, a CT on the back will probably last you four years minimum and golly, where’s the profit in that?

    If you are inclined to try a CT on your rear wheel, be advised that not all CTs will work. You can refer to the following site for a list of tried tires for your bike:

    For some pointer about installation, this video may be helpful:

    The best thing to do is to have them installed. Find a Car Tire shop that is not afraid to do what you want. Something not quite main stream is probably what you want. Make some calls and ask some questions. They had to hit 116PSI of air in my tire to set the bead!

  59. Figured it out yet, Mr. Trow?

    You lack knowledge and experience, and it shows. I applaud you for having actually gotten in print. But not for your content. You failed to adequately research the topic and spewed forth only your opinion, with out backing it up with any factual evidence or testing.

    And your opinion is wrong. Frankly, I only went to the darkside for one reason, motorcycle tire manufacturers stopped making tires that lasted more than 10k miles. And discontinued tires that did. Motorcyclists have been fooled into thinking that 4k miles is acceptable tread life. It’s not. Especially for those that ride 30-50k a year. The old bias ply motorcycle tires lasted 20k or more. A good car tire on the back of a powerful sport-touring bike will still last 40k miles. And provide all the grip to drag hard parts if the rider so chooses, as well as providing better tracking in marginal conditions.

    To the motorcycle tire manufactures, STEP UP. Provide tires that last, that still perform. Longevity and performance are not mutually exclusive aspects. Stop wasting time with race spec tires for sport bikes when no rider can make full use of that on the street. And when your “newest” generation of tire performs worse than the last, STEP UP, and discontinue the “newest” tire and bring back the previous version. Or, just maybe, use actual testing to determine what your young engineers have thought up before bringing it to market.

    You waste our money, we will stop buying your products. Never, ever forget that. There are alternatives.

  60. Eric, you pegged it! I remember when auto manufacturers swore that fuel injection would never work because it was too complicated for every day use. Spark plugs once lasted only five to ten thousand miles, if you took good care of them and constantly adjusted their gap. Other ignition components often lasted for shorter periods (points and condensers). And most cars and motorcycles needed top end work (valve jobs) at 20-30K miles.

    Now, today, we have plugs that last a 100,000 miles. Ignition components last the life of the car’s body. Fuel injection is not rare, it is common. And engines can easily go 150,000 or 200,000 miles without touching the valves.

    So, your point about purposefully limiting the life of motorcycle tires is dead accurate! Oh, yeah, I run a Michelin Alpin PA3 ZP (run flat) on my 2012 Goldwing. It sticks FAR better than the original OEM tire, and I expect four times the mileage out of it. And it is more puncture resistant. And it won’t disintegrate and put me face down on the asphalt. It is a top quality tire, so it cost about the same as a motorcycle tire, initially. But the much longer mileage drops the price to 25% or less than a motorcycle tire…and even lower if you count mounting costs.

  61. I too did a lot of research before going “darkside” on the rear of my GL1800. One thing I always asked anyone who disapproved or bad-mouthed the practice, was “Have you ever actually tried it? Of course the answer was always NO.

    On the flip side, virtually 100 percent of the people that approved and supported the practice, had indeed done it.

    39,000 miles later, I’m on my third Pirelli RF on the rear, and I will never go back to a round tire.

  62. I think this question can only be somewhat resolved by a randomized double-blind test.

    – Get several bikes of the same make, model, year and trim. As many as possible.

    – Mount car tires on one half, motorcycle tires on the other.

    – Assign them randomly to riders while preventing them from knowing which tire they are riding on. Ideally, riders won’t even know what the test is about.

    – Take a test ride on a predefined (ideally closed) course with varying but standardized conditions (sharp, straight, uphill, downhill, braking, acceleration).

    – Collect impressions from riders right after the ride. Do not let them see which tire they rode on.

    – Randomly assign riders to bikes again.

    – Rinse, repeat.

    A test like this, if done properly and with a sufficient number of diverse riders, would give a pretty good picture of whether or not there is an observable difference in handling for a particular type of bike.

    There should also be a way to scientifically test the contact patch size and grip at different lean angles, which would give a better picture of safety.

    Until tests like these are done, “darksiders” will have anecdotal evidence on their side while “the orthodox” will point to theoretical.

  63. It would be difficult to mask the knowledge of the tire used on the bike. All you must do is LOOK at the rear wheel and you will know what is what. The rider would need to be seated in such a way they were not permitted to look at the rear of the bike.

    Also, with dark side riding it has been said that the pressure on the rear tire must be adjusted to the weight of the rider to optimize handling. So a fair test would need to include this step.

    I believe a more relevant picture could be had if ALL the theorists were not permitted to make a statement UNLESS they had actually had some real life dark side experience. Let me put it another way, their opinion would not be considered in anyway relevant by any party UNLESS they had objective dark side testing and/or experience to back up their claims.

    Most folks who have experience riding on the dark side speak favorably of it. A very small number who have tried it have decided they did not like it. Most of those who have tried it and continue to subscribe to this practice say nothing! That is OK. Actions speak louder than words.

    Once I encountered a person who had ridden on the dark side and had given up the practice. His rational for riding on the dark side was to extend tire life. At the time he was a hard core, high mileage rider. He confided that a few years ago a friend of his was killed in a motorcycle crash when somebody turned in front of him. He said somewhere in there, this sobering event caused motorcycling not to be so much fun any more. His 30,000 mile a year riding dropped to about 5,000 a year, the same as most other riders. He realized that replacing a tire once a year was not a big deal so he quit using the car tire on the rear of his bike.

    Riding on the dark side has never been due to a specific complaint about the price of a motorcycle tire, but more about having to replace them with such great frequency when one must replace multiple rear tires annually.

    If you do not log a high number of miles annually, dark side riding may not be for you. There are trade offs, but most of these have been found to be favorable by those who ride on the dark side.

    The only trade off I have found that could be considered negative is this. It take a bit more effort to initiate a steering lean. I as only ever aware of this difference one time in dark side riding and I have about 6,000 miles on my rear tire now. We steer our bikes by counter steering. A more aggressive counter steering maneuver compensates for any steering latency the car tire may produce and our bodies quickly learn and account for these differences. Different tires handle differently and we are really just talking about a different tire after all.

    Motorcycles have been on the road for as long as gasoline powered cars have. The first motorcycle design was show cased in 1884. the first car show cased in 1886. Until sometime in the 1940s car tire and motorcycle tires were much the same. They even used the same bead design. The motorcycle industry decided to optimize motorcycles during this period and among other things they changed motorcycle wheel bead design. For the first 50+ years motorcycle tires and car tires were quite similar. Probably the biggest improvement in the motorcycle tire was the small increase in steering speed. This may be critical if you are a motorcycle racer, but hey, I’ve seen a youtube video of a guy on a sports bike with a car tire on his rear wheel hitting the twistees just as fast and hard as his buddies.

    Something to think about!

  64. Such a test is patently impossible, in addition to being somewhat silly. You would have to have totally amateur riders, because skilled and experienced riders check their tires carefully. On the other hand, a massive input of anecdotal data, such as “shiners in the spring catch a lot of bass in the local lake” can serve us quite well. LOL…

    I’ve already caught my lunker…a long mileage run flat, highly sticky, Michelin car tire!

  65. A test like this can be made blind. There is no reason for a rider to have to see his rear tire and those that would cheat are easily eliminated with a camera mounted on the back.

    I have two very different bikes and ride them combined 20-30,000 miles a year. ’02 Bandit 1200 will probably never get a car tire, although I wouldn’t mind trying it (I have a spare rim, just not up to investing in a tire). The ’05 Yamaha Majesty 400 scooter will get the car tire the first chance I get.

    I hate the fact that motorcycle tire manufacturers haven’t yet made a tire that’s not going to develop a major flat spot in standard sport-touring regime I subject it to. They all wear out in the middle five times faster than on the sides and I never had one that lasted more than 10,000 miles.

    Since motorcycle tires spend at least one third of their useful life squared by riding in the straight line and MC manufacturers can’t solve that problem, why not have them square to begin with?

    A car tire costs half of MC tire and lasts at least three times longer. It’s a no-brainer for me, at least on a bike that never sees sharp lean angles anyway.

  66. Since when is actual use of car tires on motorcycles with many miles on them anecdotal evidence? Anecdotal evidence is when people say not to use car tires but have never tried car tires on their cycles.

  67. Vlad, I am not sorry that you can’t see the millions of miles of evidence before you. That is your perception problem. First, there were no motorcycle specific tires in the beginning. People used ‘tires’, generic tires, most of which were made with automobiles and trucks in mind. Back in the fifties, many of us were using automobile tires because it was nearly impossible to get a motorcycle tire in much of America. There was no internet, and an interstate phone call of more than a couple of minutes could eat deeply into your week’s wages.

    Second, there are at least two major forums that gather data on the use of automobile tires (Delphi’s Darksider, with a GREAT database!). Once that data is entered, it becomes EVIDENCE.

    However, you folks with your head stuck in the sand ask us to prove a negative. You ask us to prove that it isn’t dangerous. Well, anyone with freshman logic under their belts knows that it is impossible to prove a negative. So let’s get you to engage a few neurons and rustle up some documentation that proves that automobile tires used on motorcycles ARE dangerous. Provide us with police and expert accident analysis reports that prove that an automobile tire’s performance or failure to perform caused an accident.

    We hear this constantly, “you’ll crash and burn”. WHO crashed and burned? Where did they crash and burn? Was the tire actually involved, or did they try to ride drunk and fell off? LOL… I don’t expect any such reports because there aren’t any. We are constantly on the look out for such reports.

    Please provide me with any insurance company actuarial tables that delineate the dangers of automobile tires being used on motorcycles? What? You can’t find any? LOL… That is because the danger doesn’t exist.

    I’ve been riding for over 55 years. I’ve heard all the naysayers. “You’ll die if you ride a murdercycle!”. I’m not dead, neither are tens of millions of other riders. Every time there is a change or advancement in technology or a technology is applied in a novel, unexpected, manner, the naysayers jump out of the woodwork. They often sling around jargon and try to sound like experts. What always surprises me is that so many riders start sounding like cagers, wimpy and frightened at the prospect of something new.

    For instance, we had to listen to all the ‘experts’ (they weren’t) tell us that you just can’t build a V8 motorcycle. I did in 1966, but I was far from the first. I had been beat out by over 20 years. LOL… Then we had to listen to the ‘experts’ tell us that electric starters would leave us stranded in the boonies by the thousands. Disk brakes? Impossible on a motorcycle, because they’ll twist sideways and cause an accident because they stop so fast.

    EVERY advancement in aviation, automobiles, and motorcycles has had some fainting doomsayer predicting the end of the world as we know it. Good. I want advancement.

    Meanwhile, I’ll crank up my Goldwing and enjoy far better traction, braking, comfort, and mileage than any motorcycle tire can provide me. I love the REAL WORLD performance of car tires on my Wing, as to tens of thousands of others.

    • Very good statement Doc! I am very impressed with your ability to explain how good a CT works on cycles. I was going to put one on my Yamaha Virago xv250 rear but the beads on the CT were wider and would not drop into the center of the rim to allow the second bead to pry over the edge of the rim. Do you know of any car tires that have a narrower bead? I suspect that some rims have a wider area in the center where both wider beads will fit together. Thanks!

  68. The article was correct about the passion dark siders bring to the discussion. I recently saw a video made with a go pro directly behind the rear tire that clearly showed a large contact patch and the tire not going on edge as is described by many. I was amazed with how the CT changed shape with various speed and was impressed enough to consider using one on my F6B Goldwing.

    I also agree with many that stated there is no incentive for tire manufacturers to make better motorcycle tires that last longer and cost less. They have bikers over a barrel.

    The article seemed to support the insurance – legal minded perspective of an OEM. I agree with the double blind test with video at the rear wheel.

    That test will never happen as the tire lobby would squash it, there is too much money at risk.

    Safe riding all

    • The contact patch videos I have seen show modest lean angles in smooth parking lots. I followed a car tire equipped GL1800 across West Virginia and the real-world observation was quite different. When the rider was grinding pegs I observed the bottom tread lifting off the pavement so that only the point of the square corner and some of the sidewall was on the ground. It was like riding on the point of a V. The side wall flexed and deformed so that some of it was on the pavement. Think about that. Some of the contact patch had no tread and was never intended to be on the ground.

      Moreover the rider kept the pressure low so that the tread would flex to maintain contact. This low pressure let the tire squish its sidewall when it hit a bump. Remember that the V on the ground was stiff bottom tread on one side and soft sidewall on the other. The sidewall side of the V squished on the curve’s bumps more than the bottom tread side. As the sidewall rebounded, its sideways force sent the bike into a weave.

      Bottom line: I observed an ill-handling bike with a narrow tread on the ground.

      Ride a car tire if you want, but don’t claim it handles better or has more rubber on the ground when the bike is leaned over far.

      • I will make that claim, as I point out that your powers of observation do not include a good comparison between the ‘leaned’ contact patch of the round motorcycle tire and the ‘leaned’ contact point of the car tire. The contact patch of the car tire IS larger while hanging hard into a corner. And the video I saw was not taken in a parking lot, but rather on a vigorous ride on public roadways.

        Do you know who Yellow Wolf is? If so, you might want to look at his videos and tell me which one is him running a car tire. LOL…. I don’t think you can tell the difference. You are not interested in facts, just expressing a very poorly informed, biased, opinion.

  69. For those that speak of logic, try to remember that logic is not opinion. Factual evidence gathered by thousands of individual riders, for their own benefit, has convinced more riders to continue to use a CT than to pull it off.

    As to the comment that “all the car tires were rounded at the edges” that one person made, that offers little evidence by itself. The one, of a hundred CTs I have seen that was rounded at the edges was an extremely aggressive rider. Virtually all other CTs I’ve seen on bike have worn evenly to the end of the tread life, including the two I ran for a total of 70k+ miles.

    I’ve seen car tires rounded at the edges from wear on cars too, which is often a sign of aggressive driving and/or tire pressure issues. That no more makes them unsafe for the car they are on, than it does for the bike they were on.

    There are many variables to selecting a CT for moto use. Different tires handle differently. That should be no surprise to anyone, as it’s been the same for moto tires on motorcycles and car tires on cars for as long as there have been more than one manufacturer and more than one style of tire.

    At the end of the day, this is something that a rider will investigate on their own, and decide upon, on their own. And until tire manufacturers offer a motorcycle tire that lasts a reasonable length of time/miles, people will still be running car tires on motorcycles.

  70. There are folks now using Car Tires (CTs) on Sports Bikes and they are quite happy with the performance! Search hard on youtube and you can find a demo. Search even harder on the web and you can find forums where they discuss their experiences.

  71. LOL, So the experts at the tire manufacturers say its not safe to run a car tire on a motorcycle. They say its only safe to run their “specially engineered” motorcycle tires. I think the priority in motorcycle tire engineering is to give you as little tire as possible for the most money to maximize their profit. I also think they have done an excellent job of doing so. I have been riding Darkside for the last 35,650 miles on a Michellen HydroEdge 205/70/15. Once the tire “breaks in” the edges I don’t see much difference at all in the contact patch while cornering as compared to a Dunlop 404 Motorcycle tire that is stock on my VTX 1300. Oh which never gave me more than 8,000 before having to be replaced. The real difference is the HUGH water shedding contact patch this car tire has when not cornering plus the radial design rides like a dream with superior traction wet and dry ! ( Can you tell I am never going back to MC tires for the back of my bike? ) LOL The idea that the tire can’t handle it is ludicrous to me. This car tire is designed to operate safely on a vehicle that could weight up to six times what my loaded bike weights not to mention I have about a third the horsepower providing power to it . . . and you think its going to fail ? Really ? Well, maybe you do. People believed the tobacco company’s experts for years too. LOL PS: I ride my bike hard. WOT a lot of the time just for the fun of it and I frequent roads such as “The Tail of The Dragon” often.

  72. I’m looking to install an SST (Space Shuttle Tire) on my bike.

    After all, a Shuttle can travel up to 25,000 mph, can easily weigh 600,000 lbs (up to 4,500,000 lbs with fuel, cargo and passengers) and can travel around the earth countless times all with the same dang tires!!!

    Imagine : just one tire could last me an entire lifetime AND proudly be passed on for generations to come!

    We all know a lot more than those stupid engineers who slept through their years of education, who never bother to properly design & test trivial things like tires or brakes and have no work ethics or pride in their work. Incompetence is the norm since an engineer cannot loose his job; never, ever!

    We also know that those big tire companies are only in it for the money and we know for a fact that no one on earth would dare sue them for selling us an inappropriate product since there are no regulations in place to protect the consumer.
    An it’s a fact that Insurance companies prefer to pay the consumer countless billions of dollars a year rather than pressure a big rich tire company into supplying us with a safe product.

    Yep, with an SST on my bike, I’m going to save enough money to buy me a full set of teeth and maybe even a beard trimmer for the little lady.

    I can guarantee ya that I ain’t getting me one of those stupid helmets though. Just another new fanged attempt to take my money!

    And don’t get me started on that ABS stuff…

  73. I find the “back and forth” and the sarcasm interesting…:=)
    I am new to the concept, but with over 55 years of riding, far from new to the enjoyment of motorcycling.
    When I first heard of this concept I was immediately against it. For all the reasons my mind could ponder, but I was caught up in the intense pro/con that I was reading. Again “reading”
    I slowly found that there were categories to the answers. 1)Those that manufactured, sold, or installed MT…2) Those that were caught up in the negativity of a new idea, and 3) those that had actually experienced the use. Being originally from MO., the “show me state” I believe in not proposing, conjecturing, or placing simply a slide rule to the problem, but actually experiencing it.
    As to the scientific approach or those unflappable figures of proof I find it interesting the number of prescription drug scientifically tested that are now found to cause serious side affects, or the findings that this week margarine is better for you than butter and next week not so much, or the bike tire manufacture Metzler who produced a tire that continued to cup and loose rubber and even though a great number of people had the same problem. They blamed it on under inflation(bull. I’m anal about my tire pressure and had it happen to me). They would not admit it, but amazingly they finally change their tire pattern and the problem stopped (and you think I trust their results).
    So I guess it come down to this. If you haven’t put it between your legs you don’t know what you’re talking about. If you have and it matches your handling and performance needs. Good for you.
    My jury is still out as I have just now had a CT installed and only have a few hundred on it. My MT is still in the garage so if I don’t like it I’ll have it reinstalled. Initial testing on my part says the CT will stay on…….

    • This is an update as I now have over 11k on the tire. We have traveled some of the most beautiful western states through roads that have mile after mile of curves that range from 10 to 45 MPH and up. I am an aggressive rider in the curves and though not professional I do constantly scrape the foot pegs on my 1800 wing.(I used to race motorcross) The tire has worn well. Because of getting the “all season” tire which curves on the sides I have not had any handling differences between my prior motorcycle tire and this one. Judging by the tread I have a long way to go on this tire. The ride has been noticeably smoother. One safety aspect that I like is that the tire is a run flat. Giving me that extra confidence. I have had a 70MPH blow out before. Not fun!!. I will continue my “test” and if I find that the tire is a problem I will return to the motorcycle tire

    • I did a lot of research about using a CT on a motorcycle but found very little negative feedback from folks who had actually tried the idea. The small hand full who were negative about did not report an accident or near accident because of it, they just didn’t like it. Most folks who have tried it say they will stick with it. I’ve put around 20,000 miles on mine and plan to stick with it.

      The truth is this, you CAN tell a difference. It isn’t bad – it’s just DIFFERENT. After I put almost 20,000 on one bike I bought a full dress touring bike (used). They said they’d put a new rear tire on it before I picked it up. I asked them to put a CT on it BUT heaven forbid, they could not do that. So now I’m riding around one bike that has 20,000 miles on a CT and another that has 4,000 on an MT. I’m told the MT won’t see another 4,000!

      OK, so switching back and forth sort of highlights the difference. When the MT on the touring bike is shot a CT will go on it! Does it cause me problems to switch between the two bikes? No. So why would I put a CT on the touring bike? Because within 8 weeks of buying the touring bike I put 4,000 miles on it! If I have to put three expensive MTs on motorcycles in one season, my wife will kill me!

      I encountered a guy who put 35,000+ miles a year on his bike. He used a CT. When he cut way back to about 5,000 a year, he stayed with an MT.

      A CT isn’t for everybody. if you are happy with the mileage you are getting on that MT STAY WITH IT. But don’t say stupid things about using CTs just because!

  74. I read an article on this recently that went in depth explaining the mechanics of actually seating the bead of a tire to a rim. Moreover, the largest difference, and biggest potential danger, is that there is high risk of the tire losing its seating. It’s either one way or the other, but the point still stands, that motorcycle tires rims and wheels have a drastically different size seat/bead/lock than car tires- but the article pointed out that the reason car tires do work is that essentially… you put enough pressure on a car tire that’s close enough of a size to the motorcycle rim, it may seat, albeit only partially/incorrectly. Another forum showed a cross section of a performance motorcycle tire vs a car tire, and you’ll easily see too that there is a ton more rubber to rely on when it comes to a motorcycle tire- especially in the sidewall- not to mention new sidewall reinforcement like carbon in the Dunlop q3’s…

    My personal opinion would be to stick with motorcycle tires, as I can trust their designs to allow my bike to perform when needed in high risk situations- which all riders I’m sure can remember a scenario where they’ve pushed their bike way beyond what they THOUGHT was it’s limit- and it not only performed, but saved their lives from becoming stamped by a cager.

    • I would like to know about accidents attributed to car tires used on a motorcycle. Not someones opinion or something they heard . Did the bead problem lead to an accident or tire failure? Has the difference in beads caused failures or accidents? Please publish it here so I can read it. Thanks.

  75. Coming from a long line of bikers ive been riding as long as I can remember.
    Although “the experts say” has some credibility. These days being an “expert or an engineer” isnt worth a hill of beans. For whatever reason few seem to have the skills to match the title. Dont forget, of course the motorcycle tire manufacturer will tell you all the reasons to use a bike tire. Their livelihood depends on people buying their product. Of course the auto engineer will say dont use car tires on a bike. Its a liability issue for them regardless of any actual risk involved. Sure perhaps some of these points are valid. Yes a car tire is somewhat square and a bike tire is more round. But lets also look at experience. Not just the experience of countless darksiders happy with the change up to a car tire. My experience… I ride a VTX 1800 one of the heavier more powerful rides on the market. I live in a remote part northern Canada. My driveway is 14 kilometres of poorly maintained gravel road. The paved roads are rough and full of potholes and cracks. Ive been on the road at temperatures below freezing with frost on the road, through freezing rain storms and hurricanes that took the roofs off buildings. There are also numerous large wild animals that pose a serious threat of collision. In my personal experience motorcycle tires are generally unreliable pieces of junk. Sure there are good ones but for the most part they just dont hold up. Ive had many blowouts, serious instability, lack of traction in poor weather and wet roads… The list goes on. This is with new motorcycle tires. I was going through a set a year. Then I tried a car tire… 100% improvement. I would stake my life on that. The car tire im sure has saved my hide several times. It grips the road in situations where a standard bike tire would have let go. The stability on or off the paved surface is above and beyond a standard motorcycle tire. For the area I live and ride the car tire is hands down the safest in handling and traction alone. The 99% outweighs the 1% chance that someday it “might” buckle under a condition it wasnt designed for. So its not designed for the twisties and steep banking turns . You know… Im not on a race track strapped to a sport bike. I ride for countless days at a time all across the North American continent Canada, USA wherever the road takes me. For the most part its nothing but long straight flat open road. Where flat wide car tires outshine their counterpart. There are a few good winding roads that we all love to ride but I dont take those at break neck speeds trying to see if I can touch my ear to the ground. So once again I find the car tires perform very well for these situations. As far as insurance goes historically, cars, motorcycles, boats it doesnt matter the policies often leave a lot to be desired. Perhaps some day the insurance companies will change their tune about tire choice it has been known to happen. I didnt have to convince a car tire dealership to install the tire for me. There is only one motorcycle dealership within hours of my location and they were more than happy to do the job. From what they tell me they install more car tires on motorcycles these days that motorcycle tires. Now If I was on a sportbike zipping around the happy safe streets of some city back and forth to work, sitting in traffic or making a dozen stops along the way then yes I would certainly use a tire designed for the bike. Thats not reality, ill stick with the car tire.

    • Two thumbs up. My sentiments exactly. Been riding something with 2 wheels since I was 8 years old and I’m 66 now. Used car tires on Harleys, Indians, Hondas, Kawasakis, Beemers and Suzukis. NEVER have I had a problem caused by the tires.

  76. Very well said Robert. Your experience echoes mine. I just came back from a 5,200Km ride on my Majesty 400 that consisted of over 800Km of very tough unpaved roads (check http://FarMotion.com for details). It’s hard to say where the car tire behaved better, on asphalt or off. There wasn’t a single moment where I would rather be riding on a motorcycle tire. And I did ride hard and fast pretty much everywhere – I was never passed by any other vehicle and I was regularly passing other motorcycles, from sport bikes to adventure touring ones.

    My conclusion is that any bike with low to moderate cornering clearance would benefit from a car tire (that includes pretty much all cruisers, scooters and Goldwings). As you noted, all motorcycles that are not exclusively used on the track spend a vast majority of their time rolling completely perpendicular to the road. Any MC tire I rode developed a flat spot comparable to a car tire profile after maximum 10,000Km. Only those who tried a car tire know how well it behaves in corners.

    I have a Bandit 1200 with a spare rim that I’ll slap a car tire on as soon as I can find the right size. The worst that can happen is I don’t like it and waste ~50 on a car tire (mounted).

  77. Robert. Have you any experience with mounting a car tire on a cycle rim where the beads on a car tire are wider than on a cycle tire? I wanted to mount one on a Yamaha xv250 rear rim but couldn’t quite get the last 10 inches of the second bead over the edge of the rim because the wider beads would not both go down into the “valley” of the rim at the same time.(At the 180 degree point on the opposite part of the rim.) I have to check more car and cycle tires to see if car tires always have wider beads or not. I believe the tire I tried was a trailer tire which would work with a tube installed as radial tires tend not to work well with inner tubes so they say. Thanks.

  78. Don’t insult yourself by assuming I can’t afford a Goldwing. I love Goldwings, but prefer BMW, I have several, and Hondas also.. so basically, you turned this polite commentary to a “go f-yourself” situation.. but since you can’t afford a BMW…. lol…. see ya!!!

  79. I’ve reread a significant portion of the article again. And it strikes me all over AGAIN that it is JUST an op-ed article.

    Sure, they provide comments from several knowledgeable folks, but ultimately, the opinion is not competition for the personal reports and videos of folks who have used car tires for a significant period of time. Some of these folks have mounted video cameras under their bikes pointed at the interface between the rear tire and the road.

    We have at cross purposes, those who are using car tires and almost every single one of them says they won’t go back to a cycle tire on the rear and we have those who are in the market of designing or selling motorcycle tires (and car tires) reiterating OVER AND OVER again that it is a bad idea! Some of these folks have gone have stated they gave the idea another look and AGAIN they come up with the same old stuff – not one of them once EVER saying “OK so I put one on my bike and wore it out over 20k+ miles and can honestly say it was a BAD idea. Because none of them have EVER tried it!

    So on one hand we have personal recommendations by folks who are RIDING ON THE DARK SIDE and personal opinion by those who are not.

    In the camp of those who have not, there are those who profess to be experts because they are in the motorcycle tire business in some fashion and then we have those who who are not because they take their lead from those who are in the know!

    I have had a car tire on my 1999 Yamaha Royal Star XV1300AL (Boulefard) for 11 months now and living in Michigan I’ve ridden in everything, beautiful dry roads, driving rain, ice and snow. Since the beginning of the year (2014) I’ve logged 15K miles already. I’m using a Kumho 165/80-15R. I have nearly 20K miles on it! During this period I have been happy with the way the bike handles. When that tire is worn out I’ll get another one.

    The Kumho tire rep commented on the design differences between bike tires and car tires. Among other things he stated that car tires were made with just one type of rubber while motorcycle tires were made with two or more. He said the middle band of the tire was made with harder rubber and the leaning edges were made with softer rubber. This makes sense. Softer rubber generates more friction therefore more traction. Certainly when you cornering, whether you are in a car or on a bike, you want more traction!

    In a car we are going to want the same cornering performance as we want on a motorcycle for the very same reason, we DON’T want to slide off the road! So if we ARE not going to use varying hardnesses of rubber on a car tire, we will use the hardest rubber that will produce the friction/traction required for the worst case scenario, i.e. when the car is going around a corner!

    There are additional considerations to factor in though. The hardness of rubber varies with temperature. The colder the temperature, the harder the rubber. The harder the rubber, the less friction/traction. Of course after you drive around for a while the rubber hears up and you get more friction/traction. The faster you go, the more friction the tire has and the more wear it experiences. This is why tires wear faster with high speed driving, because they run hotter, the rubber is hotter and has more friction = more wear. Wider tires wear better, probably because they provide a larger heat sink for the working face causing the tire to run cooler.

    Car tires designed for summer use are made of harder rubber than all season tires or winter tires. Harder rubber will not have as much traction on slippery roads as softer rubber will. Winter tires have the softest rubber of all. Using a winter tire in the summer would provide the best traction but the poorest wear.

    Harder rubber motorcycle tires last longer than softer rubber tires do but using them in cold weather would be much more risky. Riding on them slowly until the heated up could improve the situation over a short period of time, but they would never provide the SAME traction as the softer rubber motorcycle tire would.

    The formula for friction calls for the mass of the thing under consideration, the force of gravity and the frictional coefficient of the compound under consideration.
    Friction = Mass X Gravity X Coefficient

    Mass X Gravity is really just weight so:
    Friction = Weight X Gravity

    So given the same tire compound, the heavier something is the more friction the tires will have!

    An all season car tire will be made from fairly soft rubber as it must perform reasonably well in the winter as well as the summer. Also, it will corner reasonably well because that is what a car tire is supposed to do.

    From this article:

    it becomes obvious that the weight of the vehicle has little to do with the stopping power of a tire. It is entirely due to the coefficient of the compound the tires are made from. This would be true for bikes and motorcycles. This would be true for cornering as well as stopping.

    With respect to the lean issue and steering a motorcycle. What constitutes too great of a lean angle? When I look at the “chicken strips” on my front tires, they are about an inch wide. Since I’ve had my cruiser I’ve put about 30,000 miles on it (last 1.5 years). During that period I’ve dragged the floor boards three times. This is not a desirable thing. The bike is low to the ground and the floor boards are wide. Dragging floor boards and foot pegs is a potentially dangerous thing that can cause serious accidents. If I have inch wide chicken strips and I’ve dragged my floor boards I probably DON’T want to lean any more than that!

    Leaning to far can promote slide out. There is a reason motorcycle racers hang a butt cheek off the seat and point a knee into the road – so they cab avoid leaning the bike any more than they have too. The use body position to change center of mass when cornering so they don’t need to lean their bikes so far to do it. Leaning is dangerous. The further the lean, the more risky! The car tire on my rear wheel hold the road just fine and I can assure folks I put a pretty good lean angle on my cruiser going around curves up to 20MPH over the rated speed. I could hang a butt cheek off the seat, point a knee into the ground and take it a little faster but hey, I’m not racing!

  80. Typical theory-over-practice, parroted dogma by another parrot by another expert parrot. If all these horrific possibilities were so very likely, then why haven’t we seen these failure trends documented in the Darkside Database? The difference between all these “experts” doing their engineering and testing and the hundreds of riders effectively compiling many times over the amount of real-world data to the contrary is a result of about nil. If all this garbage about poor handling and destructive, unsafe wear patterns were true, then why are car tires lasting so much longer, and riders reporting better stopping grip and comparable to better cornering grip, even if the handling feels “different”? The article refers to “claims” made by darksiders. Well, it’s not just “claims”, it’s documented, in many more hundreds of riders than any manufacturer uses before they put something on the market. I have proven with video from under the bike that the contact patch is almost twice as large as a motorcycle tires, and in the corners, about half the tread flexes to remain in contact with the road resulting in a contact patch of about the same size as a motorcycle tire. It’s not just a “narrow strip”. Even if it is, if it holds as well or better than a motorcycle tire, then, so what? Especially given all the other benefits of vastly increased mileage, better traction when stopping and better traction in the rain, which is undoubtedly SAFER in panic situations, not more dangerous. Additionally, I have experienced NO reduction in the ability of the bike to swerve, which is the primary crash-avoidance skill. Indeed, custom chop and sport motorcycles that are using fatter and fatter rear tires with each year model have much more compromised handling characteristics when swerving than standard, cruiser and touring motorcycles with car tires. How do the OEM “experts” explain these 200+ width rear tires as “safer” handling than the 150’s, when they do NOT turn as nimbly?

  81. It’s been a few years since I started arguing in support of Car Tires (CT) on motorcycles. Since then I have put two CTs on two bikes:
    – a Kumho 165 on a 1999 Yamaha Royal Star Boulevard/ 25,000 miles on this tire
    – a Nexen 165 on a 2001 Yamaha Royal Star Venture/20,000 miles on this tire

    Some notes: Not every CT can be used on every bike. It is best to check the Dark Side Database for tires and bike combinations that have been found to work OK. They will typically provide the seating and inflation pressure required for the tire used.

    So I have 45,000+ miles of experience riding CTs on cruisers now! I’ve ridden through the mountains of West Virginia, The Dragon, The Great Smoky Mountains, The Black Hills of South Dakota. These things corner pretty good!

  82. Holy Cow (pun intended) I hope this debate gets more ink – or whatever pixelated print is called. I’ve been riding for over four decades and I’m just glad I’m not using the same kind of rubber I started out with in the ’60’s. Tires have improved phenomenally, especially for dual-purpose riding which comparatively speaking work like magic!

    And therein lies my opinion: It’s not just the tires that count, it’s the rider and the riding done that matters too. Me? I wouldn’t ever put car tires on my bike, but I’ve come to respect (some) riders I know that do – because some seem to do it well. For what it’s worth, my rule of thumb is that if you can mount your own tires, mount whatever you want to mount. If you lack even that skill and require someone else to mount your tires, use motorcycle tires. That principle may be based on an odd type of logic, but like (some) darksiders, it seems to work . . .

  83. There are some interesting- and blatantly erroneous- engineering presuppositions being made here.

    Regarding the contact patch, it does not diminish to some tiny thing whn the bike rolls onto its edge- the contact patch will stay roughly the SAME size because the thing supporting the bike is not the SHAPE of the tire, it’s the air inside measured in PSI- if the bike’s rear wheel has, for example 300lbs on it and the tire is running at 35PSI the contact patch will be very close to 10 square inches- the tire itself will simplty deform- tires are made to be flexible, that’s what they do.

    Regarding cornering and the (bad) coffee cup analogy, that same factor in a motorcycle tire induces SCRUB, which is basically reducing available friction by making part of the contact patch sliding-friction rather than sticktion. Having a sharper “edge” on the corner of the CT should raise pressure in the center of the contract patch and reduce it at the edges, where scrub is present.

    It’s tough to say whether this is a net gain or not without actual machine road-testing, or at least computer simulation, to the best of my knowledge NONE of which has been don to date.

    Lastly, the article completely disregards that automotive tires are subject to design advancements, particularly in compound (silica rubber, for example) and tread design over a much higher economy of scale than motorcycle tires, as other articles have noted.

    What would be really cool, is if the author actually tried to find someone to actually TEST the different geometries and coefficients of friction, rather than just going to the munufacturers who OF COURSE are going to CYA and say, “Oh, no, our legal team says only use the recommended tires”.

    I’m not saying the Darksiders are RIGHT, I’m just saying this article fails engineering 101.

    • Yes, more intelligent talk – ya gotta love it. The questions seem to be: Can useful (honest) metrics be identified that support or condem the use of car tires on motorcycles? Are contemporary car tires, as opposed to tires manufactured a decade ago, potentially suitable for motorcycle use – have things changed? If car tires can safely be used, what tires on which bikes and under what conditions? And finally, if my wife says that the tire around my gut is ugly, should I respond by asking if it’s a bike tire or a car tire?

      • I have over 300K miles on C/Ts on GL1800s they work great. With a C/T on the rear The Bridgestone 709 on the front will break loose first. But ride what you like.

  84. Yikes, have I got this right? Rider reprints Trow’s Darkside article a few months before he’s sent as a guest speaker at The Americade Rally in Lake George, New York! Add to that his talk will be “Debunking the Myths of Motorcycling.” Isn’t that kinda like sending Al Gore to a Trump rally?

  85. I am 68 years old and have been riding since I was 11, got my 1st Harley when I was 14 and have had over 30 motorcycle since then, hundreds or thousands of miles, and at least 100,000 with a car tire on the rear on several different road bikes. There is a very minor difference on the feel when coming out of a turn, virtually none going into a turn. There is a very big difference in improved rear braking with a car tire and I get 3 to 4 times more miles on a tire that cost about half as much. I am not recommending that anyone switch to the dark side, I would not install one on anything but a big cruiser, to each his own.

    I have never experience a failure of a car tire, I have with an almost new MC tire, properly inflated, on a Gold Wing doing 75 on a straight stretch of pavement, side wall blew out. I have yet to hear of any documented accident cause by a car tire nor have I heard of insurance failure to pay a claim for this reason. As another reader has mentioned, it would be easy enough for any of the magazines to do side by side tests on same bikes with both tires. If you did so and were truthful with the results you would probably loose a bunch of your MC tire advertisers. Until you can furnish facts instead of theory, don’t knock it till you try it.

  86. My goodness was the article bias and one sided. It is also written quite awhile ago (2012). Follow the link below and take a look at the website. Do some searches, play around with what bikes are running what tires, look at the miles posted. Then wonder if all the science offered in the article should be taken with a grain of salt.


  87. The CYA experts must sell out the idea of using a car tire for their job and insurance sake. Rider does promote advertising for trikes (not recommended by Honda) and trailers (not recommended by any manufacturer), but will not even ride on a car tire on a Goldwing to know first hand how it handles.

    I’m pretty sure you could be sued for an accident on a trike along with the trike manufacturer or an accident when pulling a trailer again along with the trailer manufacturer, and many are making their own trailers…..they should really be terrified.

    I’d rather have a engineered motorcycle tire but until they make one the doesn’t blow out, delaminate from the heat, squirm, or weight that a car tire can handle (not to mention mileage). I guess I’m stuck with a car tire. Even if that means i can’t take any riding safety courses although there are courses for trailer and trike riders.


  89. This article is one of the reasons I ended my subscription to Rider after approx 35 years. I have no interest in The Dark Side myself, but just reading this sad excuse for a motorcycle tech article made me realize that Rider was no longer a useful publication.

    I’m surprised that it is posted here on the web site, since it appears that many others feel the same way I do.

  90. Put car tires on my Honda Cub 90; they don’t work so good. However, I think I discovered the difference between an openmind and an empty mind.

  91. The one good thing about biased articles like this: I’m getting far better information from the offended riders that are passionate enough to respond…..The Valkyrie may indeed see it’s first CT this Spring.

    • You won’t look back. I followed Darkside articles for about 5 years before trying it. I ride a 2008 Triumph Rocket III Touring which has the torque to rip rear tires apart. I could barely get 6,000 miles on a rear tire. I would never go back. I can get nearly 3 times the miles on a CT. Once a motorcycle tire wears to about 50% they’re also flat in the center. I use a run flat so the sidewall is stiff just like a motorcycle tire. I’m on my 3rd rear CT. I find it grips better on wet pavement and I have never had an issue dragging my floorboards without feeling secure. In a lot of situations you’ll have more rubber on the ground with a CT. Check out comments from the Goldwing Road Riders Darkside forum or Triumph Rocket II forums.

  92. Ridiculous! Dark-Siders are the same people who thought Trump would be a great fit for the White House.
    Are they putting motorcycle tires on their cars? Maybe using all those old tubes for condoms? Who knows? Who cares!

  93. I have 2¢ worth to contribute…I have not read the article that is the subject of most of these posts.. I am motorcycle savvy though, over 60 years of Harley experience..still ride em.. After purchasing my first non-Harley and driving it 3 days cross country, I was surprised that the rear Michelin was showing metal. It had 4/32″ when I bought it (used) and it seemed excessive. Remember, I was used to Harley tire wear.
    I really like my K1600 BMW, I like everything about it…I just dont like the idea of a tire wearing out in 6k miles..
    This past fall, I found a 8″ deep pothole just 3 miles from home, at 45 mph I destroyed both rims. The tires were not going back on.. I bought a General CT tire (205/55-17) and mounted it to a new wheel. After 4K miles on the CT, I have found minimal wear. although there are things I notice…
    The bike wants to track the ruts…it will lean to the opposite of the contact side of the rut, and there is sponginess at low speeds riding 2-up. I can live with all of these issues, but have determined the ill handling is due to the corners of the tire standing the rear of the bike up higher in a turn than a MC tire. This does change the steering geometry and causes some excitement on spirited turns, and again, some sponginess is evident…The answer for me is a C/T that has a little more rounder corner and stiffer sidewall, like a runflat.. Gonna try that next…

  94. Buy you a runflat exotic car tire mount a camera and then there is the proof. I run Kumo and others I like the fact I can run loaded on cross country runs and not have to w0orry about changing tires before I get back I get around 20K out of my car tires and I’m happy. I know of several riders that run the runflats and they have saved their lives!

  95. I would like the motorcycle magazines do tests on a car tire on tbe back of a motorcycle instead of just guessing. This artical has no scientific data. It is crap.

  96. Theory and speculation is all I read.
    Do 5000 miles on a Darkside Goldwing and then report to us your findings.
    Opinions are…., well you know the rest.

  97. 95,000 miles on my 02 Honda VTX 1800c and I’ve had the Michelin Hydroedge 205/65/16 tire on the back for approx. 12 years and over 65,000+ miles on it. Never expected it to last this long and work so well… wish they still made that tire! So as before, Im now researching to find a good replacement, although I will still probably get 10,000 more miles out of the old Hydroedge!

  98. In the 5 plus years this string has been going there has not been one documentation of an accident caused by a car tire on a motorcycle. I guess all darksiders are just better riders because all the “experts” know they should all be dead or seriously injured.

  99. Started riding dark side in 1978 on a rigid frame chopper (Winston Sam on a 16″ rim). 81 Gold Wing, 2006 Road Glide and now a 2016 Road Glide Ultra.
    Interesting that motorcycles were delivered with CTs before MTs were developed in the 50s. Nobody had concern then, even with the lesser quality and lack of technology.

  100. I like the car tire idea; car tires last longer. I drive a little 650c.c. One lunger to work every day. It weighs like 360lbs. or something close to that. I can get around 3500 to 5000 miles from a tire. That is a ridiculous figure for a bike that size. Problem is they build motorcycle tires like everyone is a track rider. Those @$#! round faced tire only get about 1.5 inches of surface area used while commuting. They think everyone drives switchback constantly. Ridiculous completely rediculous!

  101. As one who has ridden a dragstrip mc tire on the street (no tread, less than 10 psi) I cannot claim to be too smart, but the issue I would worry most about using a car tire on a motorcycle (it was common when folks starting using like 360 width on the rear of their mc before the mc world began making mc tires that wide) for that nice fat rear end. personally, and this is only my OPINION, so I am not saying I am right, my biggest worry would be, should there be an accident and the tire choice is in question, is explaining to your insurance company at best and being sued bigtime in a civil lawsuit with injuries to a judge and jury. In my case, the big fat warning on the drag strip tire that says “NOT FOR USE ON HIGHWAY OR PUBLIC ROADS” would be enough to sink my boat. that being said, I can understand being a dark sider if I was assured that I would be riding only on straight roads with no possibility of having to maneuver quickly at any time. but then again, I see the stunt cars riding on 2 wheels once in a while, but we could be going back and forth on this issue all day, and we have, it’s just that I am a fraidy cat when it comes to insurance companies and jury trials. I would think that one might be all alone because your insurance company rep already cancelled your policy and bailed from court after admitting his or her client was at fault, so there is nobody next to you representing you in court that you could talk to. seems a lot cheaper IN THE LONG RUN just to bite the bullet and buy a motorcycle tire, I am not saying that I am correct. For more information, go to my website and see what wile e. coyote’s opinion is as I always found him the voice of sanity.

    • That’s what it comes down to for me, will your insurance cover me if you have an at fault accident and take out me and my bike. I’ll never run a car tire but if my brother wants to run one it’s his business, as long as insurance will still cover his liability.

      Anecdotally it seems the insurance companies have little to say on the issue. Most policies include a clause not to “modify” your motorcycle as an out for insurers. By that token I couldn’t ride with any of my family, we have everything from ape hangers to ammo can saddlebags and not a stock bike to be found.

  102. the thing that grabs me is seeing a REALLY fat mc or car tire on the rear of a mc and seeing only about several inches of tire vs. road contact patch. seems like a waste to me, but I would want a 360 fat car or mc tire on my bike like I would want a woman that has a butt 3 feet wide. my personal preference for the hi-performance Harley type bike I built is a 180 to 200 width… not too big, not too small. this wide tire thing that seemed to peak about a decade or so again has clearly pushed the issue up a notch or two. just my worthless 2cents. sorry about getting off-topic. but some of you Harley types will remember when having a 150 width tire was the bomb, so much so that even the Harley factory started making kits for it by compromising by using a skinny belt and later started making them a factory setup, not just a kit. I did, and do, remember seeing BIG TOURING HARLEYS with fat fenders using the 130, they looked like bicycle tires on the big touring models. I use a chain so it does not matter. over a decade ago when s & S started making a 96″ motor and then THAT was the hot set up then, since then we have aftermarket motors in excess of 150 c.i. Now even Harley is making big inch motors with their newer designs with water and oil cooling plumbing to reduce motor heat. I think it all boils down to personal preference in these matters, not touching the car vs. mc tire thing on this post because it has already been discussed to heck and back again already here. yep, off-topic again.

    • The wife has a 230 series tire on hers (stock) and it handles like a pig. I can’t imagine a CT will handle any better.

  103. Mastering the appropriate question to ask is actually a lot more imperative as compared to having a complete reply. First-class questions dispute your own reasoning. Research studies are rather unambiguous that we nurture people that tune in to us. Our mission and goals are unquestionably centrally who we are and who we would like to be. In the simplest of terms, proper questions are our instrument for supporting to observe the true reality around us instead of shadowy depictions of it. Ask elementary questions about the things which all others takes for granted. People are compassionate. They need to enjoy a fantastic discussion with you. We achieve things for several different reasons. When you ask someone as to what fulfills them, it opens the door to discovering an issue that is constantly extraordinary to that person. It can be a miraculous moment for others when you invite them to talk about their goals with you. There are instances when you don’t have to give advice.

  104. There is no chance of a catastrophic failure, but the tire shape REALLY matters for optimum traction. Where I would not worry about it is a sidecar of course, or a trailer bike, or a pure highway bike doing that iron-butt bullshit.

    I personally claim to not own a motorcycle after 100 miles, it just sucks for me, so i plan 100 mile legs at the most. I love tapioca pudding but not for every meal.

    anyway, if you need a v or rounded profile, that is not a concept that is ooff-base or something, it is just that people want more than 3/32″ tread on $300 tire , which could easily be done except for that then they don’t sell enough tires and then cant afford to make them, or it simply isn’t worth it

  105. I find most often those with the greatest ( negative ) opinion have the least experience on the dark side. I for one have many miles on a car tire and find it very suitable for my riding style. The most recent road trip has been to Homer Alaska (June 2018)
    The many different road conditions along with cold wet weather made for a challenging journey to say the least. The one thing that I did Not have to think about was my tire handling or longevity. I don’t recommend the dark side to a novas rider due to the low speed tracking issues. I do recommend the opinionated riders ( or not ) without Dark Side experience to try it before you comment. Good luck and safe riding.

  106. go to gl1800ridersforum theres a darkside post on miles on a ct up to 13 million on them. no issues and that’s just those that have posted and know about the post. writer for magazine should go get a job with cnn !! would fit wright in . sad !!

  107. Build the bike to operate as a system? Apparently Harley engineers don’t run the baggers at 80 mph on the freeway to feel the wallow that they do. That’s ok though because the aftermarket on stabalizers is thriving. Fixing the stuff that Harley ignors while they are “carefully building a balanced machine”. Same with their stinking 1950s technology suspension systems. Once again the after market has to provide the fixes.

  108. Firstly, let me say as a very, very lapsed touring bike rider from decades ago I’d never dream of putting a car tyre on a bike. On the other hand I’d be more convinced by the motorcycle manufacturers argument about how their tyre selection is carefully made by engineers to match the characteristics of the bike if I didn’t recall that the first thing we used to do upon buying a new or second-hand Japanese bike was to have the standard-fitment tyres removed and some decent rubber installed, like Metzelers – irrespective of how much of the tread was left. We used to call the Jap tyres “Nagasaki ditch-finders” as they would last for ever but had virtually no wet grip.

  109. Would I put a car tire on a ZX10 …. Oh Hell No! But on My Vulcan Nomad … Oh Hell Yes ! Now the same people that tell me ” You Going Die ” are the same people you see on the news that Tried to lane split at 70 MPH or have tried to turn Bear Creek Road into the Bear Creek 500 and ping ponged of a few trees ! I’m an OLD biker that has been around with lots of miles under my belt & WILL be around with lots of miles on my car tires No Doubt !

  110. Been through 2 MTs in under 7000kms on my gl1200 with sidecar…. 2 in one season…. At $200 a pop for tire alone this is serious… I aint rich and id rather put that money into the fuel tank.. As the bike is heavy and the sidecar wont let it lean, seems to me darksiding is the only logical choice….

  111. Hi Guys here in Australia we have the darkside. Let me explain. My interest in car tyre for motorcycle was 1st thought about 12 years ago. While riding with a group of Ulysses members on a weekly ride. At that stage I owned an old 1993 XJ600 an never thought any more about it. It had been 25 yrs since i had ridden a motorcycle and wasn’t to sure whether to keep riding or not. Glad I did make the decision to take the bike riding back up. With that said I progressed to 1997 Virago 1100 A bike which i have ridden for over 50k. I love my old Virago I can go outside and know that I will not have any problems. I forgot to mention I am now 75 April makes me 76. My car tyre has 7500 ks on it and have ridden where I wouldn’t have gone with the Motorcycle tyre. Gravel and country roads. Rain or wet roads no worries. My main reason to try the C/t tyre prices.almost $300 a tyre for a distance of 5/6000 ks just doesn’t make it viable for a pensioner. The Hankook sticks to road like shit to a blanket. A wider tyre too normal tyre 140/80-15 Car tyre 165/80-15 with 40 lbs

    • I have close to 150,000 miles on f different car tires on three different motorcycles including 1999 yamaha royal star boulevard, 2001 yamaha royal star venture and 1993 Honda goldwing gl1500.

      I get between 30,000 and 35,000 miles on a car tire before they are done. I’ve never had a problem with them and ridden on every kind of road you could imagine including twisties of all types including the tail of the dragon, two track roads, dirt roads, wet roads, bumpy roads, even roads with a bit of snow. No ice though.;

      Besides the longevity another advantage of that rear car tire is that if you get a FLAT, YOU CAN PLUG IT. Found that out on a 7,000 mile tour in 2018!

      They take a licking and keep on ticking. I ride around with my 200+ pound wife on the back. They can also handle a heavier load!

  112. I bought a used Goldwing and it was dark sided. It also came with an extra rim with a motorcycle tire mounted onto it. I rode it for a few months with the car tire and it was mostly OK, except if there was a rut in the road. It would jump into and “track” the rut. It scared the hell out of me a couple of times. I put the motorcycle tire on and no more “rut” problems. Just my experience.

  113. I have a 2011 Harley Street glide with a 180/55/r18 rear wheel. How do I find a conversion size to go to a car tire?

    • There are no conversion sizes. Just look for a car tire with similar dimensions (+-5 in the width is usually OK) and if you are lucky to find it give it a shot. I would recommend not to bother unless you ride at least 20,000Km a year though.

  114. i had a 1200 Gold Wing in the late 80s that needed a rear tire and i couldnt afford that at the time, but i has a few nice 15 in VW Beetle tires. well i ran that tire over 50,000 kms, was only GW i ever did that on.and have had 12 others since.

  115. I’ve ran five car tires on my gold wing. All fun flat. High speed thru the twisties. Will never go back to motorcycle tires. Too many flats on motorcycle tires. Not a single one on all five car tires.

    Gold wing forum. Shuckaduck put a car tire up against a motorcycle tire anytime in the twisties or high speed never let me down

  116. I have been riding since the 70’s all motor cycle tires had a flat shaped tread in those days .I had Goodyear tires on my bikes and the tires would start to dry Rot before they would wear out with that tire shape then metzler ( a newbie in the u s market then) had the round shape soon I could find the good old style tires and had to switch never really liked them even today .I’ve know people going to the dark side and have riden their bikes no problems at all a d they last forever even riding hard

  117. Show/find me one motorcycle company, world wide, whose engineers put car tires on their motorcycles. That’s all I need to know. Even if it was just 1, I may take a look and give some consideration to it. But, there is no one.

    • I agree with the point that car tires on bikes are not standard, but how does it follow that because car tires on bikes aren’t standard, at point of purchase, they ought not to be used? If that was the case, what explains the billion dollar aftermarket motorcycle accessories/farkle industry? From exhaust systems to suspension to brakes, by definition, aftermarket accessories are . . . well, aftermarket; they are not included in the items engineers approve, yet they are used and often improve pleasure and performance. By the way, I doubt I’d ever use car tires on a motorcycle, but the reason I’d never use them has nothing to do with manufacturers not approving or providing the option.

    • My service manager at Honda dealer runs one. Go to gl1800ridersforum. There’s a post with 16 million miles. Ya 16,000,000 without any issues. I have over 300,000 on them. Won’t go back. So you can get a tire for 1/3 of cost and lasts 3 times longer and is safer but your scared. !!! 😂. StY on the porch. Will wave as I go bye. 👍

    • No one needs to prove anything to you, but you may want to find a motorcycle company that puts decent OEM tires on their bikes. You do you and keep telling yourself that it can’t/shouldn’t be done while those that tried it never went back and keep racking hundreds of thousands under their car tires..

  118. I guess I missed the part where you went dark side. Just another waste of time listening to someone interview the motorcycle tire experts. What did you think they’d tell you?

  119. so a few pointers it illegal ,
    it voids insurance and makes you liable to be sued in event of accident,
    and as my mates wife found out cancelled his life insurance leaving her and the kids destitute after he was killed when the tyre failed on his Harley and all for saving 80 dollars on a tyre such a dumb as thing to do ,
    also anyone caught fitting the tyre are legally liable under chain of responsibility laws and liable to be sued and imprisoned if found guilty and once again for saving 80 dollars on a tyre lol this is laughable seriously why would anyone risk it .

    P.s. i now know two people whom have died when there car tyre failed

  120. First, David is correct!! Thank you David. A rational Light in the Din! And don’t we ride for fun?? Yes and Safety first Always!!

    As a Tire Designer of 40+ yrs I get this question often. Here is my last reply.

    Good Question! And the answer is NEVER mount car tires on a Motorcycle! Tires are designed differently for 4 wheel applications and can be dangerous if used in a two wheel application.
    Lets just pick ONE big design point difference that is common to most automotive tire designs. There are always design variations and exceptions but this will get you in the upper 90 percentile bracket of safety. Automotive tires are designed with 2 steel belts and the wire angles of the belts range from 21 to 27 degrees from the rotational axis for most designs. The first belt angles one direction and the second belt angles the opposite direction. This this done to compensated for the lateral pull force that is developed from the belt angle. But there is a catch. Geometry! The first belt is laid closest to the axel and the second belt is laid on top of the first belt. Well the second belt has a slightly larger diameter than the first so the lateral forces to the inside and outside are not equally offset. There is always a slight residual lateral force on and automotive tire. Motorcycle tires are designed with ZERO Degree steel belts for this very reason. No residual lateral forces. We even switch the angle of the first and second belts for Japan as they drive on the opposite side of the road. Residual forces are designed to be compensate for road crown for one point. There are more but that is a PhD discussion and takes several years.

    As I said, good Question ! You get a Gold Star. Always remember, the only bad question is the one that did not get asked!
    Motorcycle tire cost more mainly because the production numbers are small resulting in higher operating costs.
    As for O.E. vs Aftermarket. Yes O.E. often look at cost vs. performance
    on their selections. If you own a Harley, as I have 2, you know that their business model is to sell you $10k plus of accessories to get you bike set-up like you wish. Brakes, Tires upgrades etc. AS for BMW, as I have 3, They came with Tier 1 Michelin tires but I still changed them to a different tier 1 Michelin as mileage was not my priority.
    As tire manufactures have tier categories based on cost, application and performance.
    Tier 1,2 and 3. As in Michelin is Tier 1 and Uniroyal is Tier 3. Michelin owns BFG and Uniroyal.
    Also some customers just want a tire to get to work ($120) and others want a tire to tag the Apex’s ($220+). The people just wanting to get to work will not pay for a low millage (Soft Compound) high performance tire and don’t need it.
    Thanks! Ric


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