Erasing Doubt: Car Tires on Motorcycles

The forces placed on a car and its tires during cornering are primarily lateral forces that try to push the car and the tires sideways across the pavement. Conversely, as a motorcycle leans into curves, the cornering force is what is known as camber force. In other words, the force comes at an angle down through the bike and into the tires, instead of across or laterally as with the car. To demonstrate this, grab a pencil with an eraser on one end. Angle the pencil at about 45 degrees, keeping the eraser in contact with the paper. As you press down through the pencil shaft, you are demonstrating camber force, much like the forces common to a cornering motorcycle. The harder you press, the more firmly you plant the eraser into the paper and the pencil resists sliding. Which eraser provides the better contact patch on the paper when the pencil is leaned and pressure is applied: a well-rounded one or a square one?

Which eraser shape provides the best contact patch...this one?
Which eraser shape provides the best contact patch…this one?
Or this one?
Or this one?



(This article was published in the July 2012 issue of Rider magazine as a sidebar to Tales From the Dark Side: Car Tires on Motorcycles)


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

Letters to the Editor: Dark Side


  1. A pencil eraser is not filled with air. While an eraser is rubber and has some flexibility, a car tire on a motorcycle does not ride up on its edge as your pictures illustrate.

    I’ve been running a car tire on the rear of my Kawasaki Vulcan 2000 for about 8000 miles. I have yet to find any situation in which the car tire has not been able to perform equally, if not better than the last Metzler ME880 motorcycle tire I wore out in 4500 miles.

    Evidence shows that the car tire flexes at higher camber angles to maintain a large contact patch with the road. As the motorcycle leans, the contact patch gets narrower, but longer. The contact patch for a car tire at moderate lean angles (like the maximum lean angle of a cruiser style motorcycle like mine) has just as large of a contact patch as a motorcycle tire.

    Perhaps there’s some way of actually testing this and measuring the contact patch size and shape of a real car tire at high camber angles, instead of using the flawed comparison of a pencil eraser.

  2. Frank, I’m sure they won’t perform any real-world testing. There’s too much fear involved, as well as corporate sponsoring.

    Unless you’re using a super-hard compound, or a low profile, narrow sidewall tire with no flexibility, the eraser thing is so much trash. Absolutely irrelevant.

    San Antonio, TX

  3. I have put over 30,000 on 2 different “car tires” on my honda goldwing. i would not put another “mc” tire on the rear of my wing if you GAVE me the tire!!! the car tire is so superior to the mc tire, that there is really no comparison.

    • Your making no since what so ever! There is just no way a car tire handles better then a MC, seems the only way to get the truth out of an ct user is when they come back to mt, other then that it’s a bunch of crap.

      • Spoken like someone that already has an opinion, but no experience to back it up.

        Why don’t you leave the car tire on a motorcycle discussion to those with some actual experience in the matter? I’d trust what Seventhson says about this issue more than you because at least he gave it a shot and decided he didn’t like it.

      • I’m on my second CT on my Strat and won’t go back to a MC tire. I do long miles and put at least 20,000 miles per year on a bike. Some bikes work better than others with a CT with bike weight seemingly to be a factor. Some riders are more experienced than others as well.

        I would not recommend a CT to a new rider, but would not hesitate recommending to a seasoned rider (I’ve been riding about 45 years) with a heavy bike

        Dangerous? Not at all. There are advanbtages due to larger tire patch on the road and enhanced braking.

        Is it for everyone? Certainbly not.

        The bottom line is try it if you wish. If you don’t like it, switch back. If you like it, stick with it.

        There is no reason to flame whether you like or dislike a CT. We don’t all ride the same kind of bike either.

        Ride safe.

        • Thank you!!! You just summed up years of bickering on multiple issues. It’s so simple, try it if you want to, stick with it if you like it.
          I ride with a full face Shoei helmet and ride with several other people that don’t like them because “they’re not safe” “they make you claustrophobic”. “You can’t see as good”. “They fog over” and multiple other ‘excuses’.
          You are right, these aren’t excuses, so to speak, but ones view on why they don’t want to (or want to) use or wear something. We all ride a little different from everyone else, so just goes without saying some things work for some of us but not for all of us. I don’t agree with the car tire idea but have never tried it so it leaves me with an opinion without any experience behind it. On this, I just choose to pass, much like my friends that won’t try a full face helmet or padded riding gear as it too gets in the way.

      • If you don’t use a car tire on a motorcycle you don’t know crap. And if anyone says that car tires handle better they are partly lieing. They follow ROAD cracks and ROAD imperfections a lot more than a bike tire. I have 51,150 miles out of two car tires and they grip a hole lot better then bike tires in the rain panted pavement in the rain and ice. Dragging pegs cause the car tires to slip a little. It sounds like most of you a fairly new riders and need to look at motorcycle tires of the 60’s and 70’s. Ride them at 120 then ride a car tie made in the 2000’s, I think you’re attitude will change.

      • The motorcycle world is basically made up of two kinds of riders. People who have tried both CT and MT and swear they will never go back to a MT ever because CT is far superior…

        … and people like yourself who have zero experience on a car tire but insist they know what’s best for everyone.

        A wise man once said, Better to remain silent and be thought a fool, than to open your mouth and remove all doubt.

        • You’re right about one thing, there are two types of riders: Those who have been down and those who are going down.
          The debate over a choice for a rear tire, in my opinion, fails in comparison to more regulations constantly being shoved down our throats. I’m thankful we can still ride when and where we want (for the most part) I think keeping the camaraderie in case another rider just might need our help ranks a little higher..
          Calling names over the choice of a tire, really? State your opinion, back it with facts if you have any, and move on but quit the name calling and belittlement. I don’t want to have to respond to a civilian for someone else’s poor mannerisms.

          • Albert, what name did I call you? Here’s the entire post for you…

            “The motorcycle world is basically made up of two kinds of riders. People who have tried both CT and MT and swear they will never go back to a MT ever because CT is far superior…

            … and people like yourself who have zero experience on a car tire but insist they know what’s best for everyone.

            A wise man once said, Better to remain silent and be thought a fool, than to open your mouth and remove all doubt.”

        • There is a third kind of person…. One that darksiders never like to acknowledge or hear about… The ones that have tried CT and returned to MT…

  4. 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 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 !!

    • You are accurately describing the only negative aspect I’ve found to running a car tire, and that is the way the bike responds to highway ruts and pavement seams. Yes, the bike tends to “wallow” in ruts, and changes in pavement elevation (such as bumps or patches) tend to make the bike lean towards the lower elevation.

      Our pavement in this area of the country (Oregon) is in good enough condition that we don’t have that many ruts, and even where there are, it’s only a minor issue. In my opinion, the advantages far outweigh that minor problem.

      Not everybody likes a car tire on their bike. It happens to work great for me.

        • Sure, if you don’t know how to ride. Even with a motorcycle tire, road surface irregularities can cause an inexperienced rider to crash. The effects I’m describing are really minor and very easy to manage.

          Let me guess, you’ve never ridden a motorcycle with a car tire, have you Ron?

      • I really don’t need to try a ct as two of my friends had them and one recently took it off because there unstable as is reported by everyone that returned to a mt. Not sure who you guys are trying to fool but your only fooling yourself. It seems the only way to get the truth is when someone stops using one. Sometimes saving a few dollars just isn’t worth the savings.

        • I’m not using a car tire to save a few dollars, try TEN times the savings. $250 for a motorcycle tire that lasted me 4500 miles vs. $100 for a car tire I expect to last me 20,000 miles. This with a tire with EQUAL handling, BETTER traction, SMOOTHER ride, and more durable than the motorcycle tire on my heavy cruiser (Vulcan 2000). The savings is just the icing on the cake, there’s more reasons than just money.

          Sure, a few return to MC tires because they didn’t like the feel of a car tire. The vast majority stick with it and many wouldn’t trade back to a MC tire if you bought them the tire (negating your argument that people ONLY do it just to save a few bucks).

          I plan on trying a MC tire again (I’ll try an Avon Cobra this time) after my car tire wears out in another 12,000 miles, just to get a comparison.

      • What are you talking about, mileage? EVERYONE agrees they suck on anything but perfect pavement but following a person on unfamiliar roads around a corner you need to drop back or take your chances there isn’t a fluctuation in the road because now your at the verge of a blink of an eye accident period! Admitted by MANY that have come back from using a ct is it’s not for new rider which might think is cool after reading ct users foolish posts! And the only reason to use one is because one can’t afford a real motorcycle tire and are willing to sacrifice the superior handling of a MT. Promoting a ct is brainless!

    • Had you chosen a narrower tire instead of a 205, you may have had a much different experience. Fatter is not always better. Researching the proper tire is very important. Compounds, width, run flat, std, DS or double DS?? All important aspects of the equation.

  5. I forgot to mention….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.

    • I’ve heard that a car tire can make an existing issue (that perhaps isn’t evident with a MC tire) worse. I’ve read reports of some riders experiencing wobbles at higher speeds because the car tire accentuated problems with loose or worn our steering head bearings (Haven’t been doing any wheelies with your Stratoliner, have you? 😉 )

      The tire you’re running on the front may also have something to do with it. When I bought my Vulcan 2000, I mounted new Metzler ME880’s front and rear. Never experienced any wobbles or instability, EXCEPT if I took both hands off the bars at any speed (Y’know, sometimes you have to adjust a wrist cuff on the jacket, or it takes two hands to open some jacket vents). The bars would start wobbling gently and build up quickly to a death wobble if I hadn’t have grabbed them! When the rear tire wore out in 4500 miles and I put the car tire on, it didn’t change that behavior – the wobble would start immediately if I took my hands off the bars for even a moment.

      When the front ME880 wore out, I put on an Avon Cobra. The wobble is now completely gone.

      You are right though, I don’t know how a car tire would effect anyone else’s bike but mine, except from the firsthand accounts of other people who have tried it. Your experience is different, thanks for sharing.

      • Sorry Buddy….the wobble only happened with the car tire. My steering and suspension are in excellent shape. I have had my bike up to 130 MPH(controlled access highway, early Sunday morning, no traffic) with no hint of wobble…I would never try that with a car tire for fear of killing myself. You can make all the excuses you want for why my bike might wobble other than the crap car tire, but it is what it is….a bad idea. My 2 sons are skilled riders(one races sport bikes, the other is a skilled motocross rider) and I refused to let them ride the bike until that piece of crap was removed. Is that clear enough for you.

        • For stability, everything has to work together, tires, suspension, steering.

          I have no doubt that putting a car tire on your bike made it wobble. But that alone doesn’t make a motorcycle wobble. If it did, then why doesn’t it make my bike, or thousands of others wobble, too? There has to be something else “off” and the car tire is accentuating it.

          I’ve had my Vulcan up to top speed of 115 with the car tire without any handling problems or wobbles. Even up to 70mph on gravel. Solid as a rock.

          So it didn’t work for you. Works fine for me and thousands of others. Even those with Stratoliners.

        • I’m sure the only way to get the truth is to compile the hundreds of post that ct users wrote themselves from wobbling, tracking, bead dosent fit a mt rim, had to bend and grind to get it to fit, bottoms out, lifts up going into a corner, have to much air pressure, to little air pressure, to much air pressure, to little air pressure and I can write that statement a thousand times easy! hard to turn going slow, tire seems to fold in…..just add more air and if that dosent work try less air LMAO.
          Thousands of engineers are wrong but a few ct users that wont admit a mc tire is to expensive for them are right. Oh my god when will they learn?????

      • This is my second Strat, so I am very familiar with how this bike is supposed to feel, even to the point where I can tell if my tires are slightly under inflated. If something is “off” I would sure know about it. I guess there is just no convincing some people that a car tire may not be the best choice, as I said earlier, messing with tires that are not specified for a bike is a roll of the dice. Yours didn’t wobble….mine did.
        The Darkside Community is like the Borg Collective…some people are unable to resist being assimilated into the fold.

        • This article has really raised the hackles of the Dark Side riders who commented here, an I guess If they want to drink the Dark Side Koolaid so be it. Changing the stability and handling characteristics of your Motorcycle just to save a few bucks seems awfully foolish to me.

        • Running a car tire hasn’t negatively changed the stability or handling characteristics of MY motorcycle. Your experience obviously was different. Some things are better, very few things (such as the highway ruts/uneven pavement issues you mentioned) are a minor nuisance that doesn’t counter the positive aspects to ME on MY motorcycle.

          Claiming that people that disagree with you and are drinking “Koolaid” because you had a different experience, or that the only reason people run a car tire is to “save a few bucks” is pretty narrow-minded and bordering on insulting.

      • And why would it bring it out? Could it be because it doesn’t belong on a bike”which it doesn’t” It messes up the alignment from front to back big time! If my MT is slightly out of align I feel it, you cant even aline a CT because of there profile! Use your head.

      • The wobble went away because your front wheel was out of balance, improperly aligned or something of that nature, when they replaced the tire the issue fixed itself because the tire was the issue

  6. Lots of theory and speculation, no actual real life comparison. Like listening to the bunch in Washington, lots of talk, very little hard facts you can belive.

    • Read my earlier posts if you want real life experience from both sides of this subject. I rode a car tire for a year and toward the end, and with about 10,000 miles on that tire, I COULD NOT WAIT TO BE RID OF IT. There is a new M/C tire available from Michelin (Commander II) that runs a dual compound tread so tire life is vastly improved….maybe not as much as you might get from a car tire, but without the constant weeble/wobble you get from riding a square profile car tire. I see YouTube Videos where riders try to demonstrate how well they work on a bike, but they will not tell you that at the limits these tires feel very edgy or twitchy….my opinion….stay with M/C tires.

      • I don’t feel any “weeble/wobble” unless I choose to ride in the bottom of highway ruts… We don’t have many rutted highways here, so maybe it’s a bigger problem in places with worse roads…?

        My car tire also doesn’t feel very edge or twitchy near the cornering limits of my motorcycle. It’s a heavy cruiser (’05 Vulcan 2000), so it doesn’t corner very far.

        I actually met a guy with a bike like yours (Yamaha Stratoliner) running a car tire, and he hasn’t experienced the poor handling as you did on yours. I would say your reported handling is the exception, not the norm.

        • I guess I have high expectations…you know, having the bike ride, handle and track as it was intended. I could drag the boards all day long with that C/T, but over all the basic nature of my bike changed enough that I no longer enjoyed the ride as much…and …after all isn’t that what it is all about??
          I just don’t think trying to save a few bucks is worth altering the nicest handling cruiser I have ever owned. The Michelin Commander II that I now ride has me back in the zone. Sometimes you don’t know what you are missing until you get it back.

        • Go read the post on the forums and all the differant fixes for wobbling tires and then come back and tell me he has the only one that wobbles, it’s now fact that if the ct’s don’t have the Exact air pressure they wobble and it will be a cold day I drive around with an air pump to accommodate this issue that some say is a minor nuisance. If you want to experience half the pleasure of riding so be it but promoting this will surely get someone killed!

        • @Ron, sure, some people have issues with car tires. Often a wobble is traced down to other issues that the car tire is exaggerating, such as loose steering head bearings, or sometimes even just the brand of tires tend to react differently on different machines. I had a Suzuki GS750 that had a nasty wobble develop above 80mph and it was running MOTORCYCLE tires, so not all wobbles are the car tire’s fault.

          You’re spouting “Facts” about something you don’t have experience with and really know nothing about. I’ve had a car tire on my motorcycle for 4000 miles, and at various pressures have never experienced any wobbling. So your suggestion that if it’s not at the “exact” air pressure it will wobble is just an ignorant statement.

          Thousands of riders, millions of miles, and no reported accidents caused by a car tire… I don’t think it’s the car tires that are going to kill anybody.

        • These cases of poor handling are from people using too wide of a car tire, or just improper size In general. One person said they tried it and it was terrible, but they ran a 205/55/17! Do you know how wide and stiff & low profile that tire is!? That is square as it gets. At least pick reasonable dimensions…

  7. I have read Erics articles on CTs for motorcycles and I see all the reasoning behind the whys and why nots for CT on motorcycle. However I have been looking for 5 years for something that makes sense about the front tire on my trike, 3 wheels, does not lean motorcycle.
    I can wear a factory recommended Dunlap out in less than 5,000 miles. I used a Michelin Pilot rear tire mounted in reverse (recommended by other trike riders) and got close to 10,000 miles. Next I tried a Metzler rear tire in reverse this one looked and felt great however I had a blowout at 70 mph with less than 1,000 miles on it. The reasons for the blowout could be many but Metzler said “never use any of our ties in any way not consistant with recommended useage. FYI the blowout happened in the Nevada desert (as if ther is any other place in Nevada) the trike settled down quickly and did not give us any problem with handling other than the original jerk when it blew. Now we were no where, no phone reception and no place to pull of the road. The temp was over 100 degrees and we were 40 miles from the next town. I never stoped, after the tire blew and as I was preparing to stop I saw there was no where to go so I leveld out at around 20 mph to see what the trike would do. Nothing happened the flat Metzler was tracking fine. I increased my speed to 30 mph and actuall set cruise control and rode the next 40 mile of straight road on the flat. Bottom line – we made it , there was no damage to the rim. The flat tire was still centered with the wheel. I origanally thought all this happened because the Metzler was a good strong tire and maybe that is why we made it the 40 miles however running the metzler rear on the front in reverse may be why it blew out. I will never know but I won’t run the same tire again on my trike. The Dunlap E3 on there now still has wear tags on it (in places) but the center of the tire is gone no it is not overinflated. Please don’t explain to me that trikes don’t lean thats why it wore that way -Duh.
    Every time I go on a forum or blog or post this front tire question I get 90% two wheel answers. The handling and wear of a CT on a two wheel anything has nothing to do with characteristics on a trike.
    So, maybe terminolagy will help. I live in Nevada and changed by registration from motorcycle to tri-car. Now would a car tire work for me on my tri-car and be safer and longer wearing? I am not looking to save $$ and purchase a less expensive tire. I am looking for safety, after wearing my front tires out every 8 to 12 months and removing them because they are bald in the middle. I guess I could only do highway miles and only turn when I have to or never ride the good fun roads which are popular with sport cars and motorcycles but I would miss out on all the fun.
    Eric talked about insurance coverage and liability of using a tire not made for the motorcycle bieng covered. I would assume that running rear MT tires in reverse would also be a coverage and liabilityt question.
    So back to question –
    Is running a CT on a 3 wheel vehicle that does not lean a reasonable approch to better safety and tire wear?

  8. Look at the “old style” Earle’s forks or the newer EML set-up (they got another name now…forget what it is). These run a car tire with no problems for your 3-wheeler (non-leaner). Take a look at sidecar set-ups as well.


  9. Ah! How ignorance abounds! I made a comment several days ago, and recently received an email. I am not sure if the reply was directed to me alone, or if it was just a general reply, but it is the only email i have received about this subject. So, here goes: Until you learn the English language enough to use it properly, please do not reply to any comment I make!! “your” was used instead of “you’re”; “since” was used rather than “sense”, “then” was used when it should have been “than”, and so on.
    I have used a runflat car tire on my motorcycle for many thousands of miles, and the tire(s) have performed flawlessly! I do not need some ignorant jerk who cannot even properly use his native language to try to tell me what is best for my motorcycle. I have done the “field testing”, and I know what works the best!!

  10. This is interesting, some with first hand experience, some with second hand experience throwing around a lot of subjectivity as if it were fact. Does anyone know where to find any hard data? “My buddy says….” or “I’ve heard…..” isn’t fact and will result in zero resolution. I’m looking for objective data and it seems many people posting here do not understand what constitutes objective data. If anyone has any, let me know.

  11. I have a Honda VTX 1300R with a Motorvation sidecar. Have been checking the darkside forums for several years. Last week I put a CT on my rear wheel. My bike shop had no problem with it on a sidecar rig, but said they would not put one on a two-wheeler.

    I got less than 5,000 miles on my last rear MT. I ride every day, at least 30-50 miles, usually more, regardless of weather (until ice makes all the cages dangerous). I had 13,400 miles on this bike when I changed to the CT. I am going to keep track to see how many miles I get out of it.

    I would probably never put a CT on my wife’s Shadow as it does not have the sidecar, but I do feel that MT’s are ridiculously overpriced. $165-200 for MT for 5,000 miles; $75 for 45,000 CT. And of course, tire manufacturers and bike manufacturers are going to say can’t do it, because they are making beau coups profits. Like THAT has never swayed an industry’s opinion? Really?

    As for the argument that motorcycle tires are high performance tires, that would be fine if I were racing for a living and needed ULTIMATE performance. But I ride on streets to work and back every day. I don’t need a high performance tire as much as I need a good, dependable, high-mileage tire. Just like I don’t need high performance car tires on my car to get back and forth to work and to the mall, etc. I’m not taking corners (on the bike or in the car) at 200 mph or road racing through Europe or trying to get down a quarter mile faster than any other human being alive. I’d just like to see MT manufacturers come up with something more reasonable. Too much BS out there, in my opinion.

    With the sidecar, all three of my tires stay flat unless I’m in BIG TROUBLE! (not really, I can still control if sidecar flies). So, I would also put CT on the sidecar and front wheels IF I could find ones that would fit, which I can’t yet. MY bike does not lean, so it’s a moot point for me, but I will be interested in seeing what kind of mileage I get on a CT on my rig.

    • You make a very valid point Prof.
      I ride an M50 Suzi. I love my all season classic CT. I never run more than 70 mph. I’ve never had a need to. I’m not racing. I like that I can feel the road, and quite frankly, engineers are those people that design cars so that you have to pull up he engine to teach one of the spark plugs. And over think? From my perspective, yes. CTs last longer because they are designed to hold up 3000 lbs. Not 800-1200. They use traction as an excuse for soft rubber, but CT tread profile makes up for that. My Suzi has MUCH better traction in turning, take off, and stops than any motorcycle tire I have ever used. Tracking? In a straight line, my MC front tire doesn’t even have any “tread” it’s neutral as far as in line tracking goes. It’s only tread is on the side walls and not enough of that. Could it be that MC tire engineers think the way they were trained to think, and that if actual cross testing was done the perfect MT might be a little more like a MT with CT tread? I’ve never had a MT that didn’t slip on wet pavement. My CT doesn’t. What the engineers have is actually as much speculation as any Darksiders. Sure, it’s “educated” speculation but did they ever actually look at car tread in design? And a MT with a harder center rubber will only slide much worse during braking, and that’s a given. No tread round surface harder rubber equals a 50 horse slip and slide.

  12. I ride a 2004 gl1800
    I have dunlop e on it and have had the front tire slide out from under me twice now once on a pool of crack sealer on a turn (I am sure any tire would slide out )
    I was following another cycle about 100 back a car pull out and stop I shut it down was not going to stop in time so going for my way out I changed lanes and the front tire began to slide out from under me I kicked it back up before the crash bar touched I ended up sideways in the other lane about 50 feet past the car so yes I was very lucky and we rode another 550 miles that day now I have followed a rider from the darkside and we were touching the foot pegs so I have to rethink my tire choice because my side walls wear out before the center of the tire from the curves just perhaps the side walls are to soft to hold under pressure like the pencil eraser just starts to crumble under pressure either way I am going to the dark side as soon as I find out what the front tire is that he was running I do know it was off of a sports bike rear tire on front and a run flat on the rear

  13. Well never being one to accept opinions I deal only in facts and experience. I have rode on a Goldwing motorcycle for the past 30 years. The last 15 have been mostly on darkside tires. I have rode from Texas to Labrador and to St Anthony Newfoundland. I have been from Texas to Yellowknife in the northwest territory and several trips to Alaska on a darkside tire. Every kind of road imaginable. Sand, gravel, dirt, frost heaves, many many miles of wet roads and even some snow. Mountain switchbacks, twisties and every thing in between.I have also made these trip on motorcycle tires. There is no comparison. I have had 3 failures on a motorcycle tire and no failures on a car tire. The CT sticks to the road better in gravel, wetroad and dirt roads than any motorcycle tire. On a heavy bike such as a Goldwing I would not get off the black top with a MC tire. You can not lean a Gw enough to get into trouble as I routinely scrape pegs and have never felt the ct slip or felt uncomfortable..
    It’s true there are subtle differences in the handling of the bike with cts and I would not recommend an unseasoned rider to use them but a seasoned rider will never worry as he is instinctively in control of his ride.
    I will say that the rim bead on a car wheel and the wheel of a motorcycle are different and the tires fit a little differently as the sealing surfaces are cut differently. the outside edge of the ct mounted on the mc wheel sits slightly on top of the rim bead. While this concerned me at first after have rode hundred of thousands of mile on the ct and knowing many other darksiders as well I have never had or know of anyone that had a problem with this issue. The insurance companies don’t have a problem with the practice so that tells me the gloom and doom many of you predict just doesn’t happen. So spout your opinions with zeal. I can At least back mine up with reality.

  14. In reply to folks talking about lateral and camber forces and contact patch size. Lets start with contact patch. Size of the patch has little to do with friction. Only the friction of the 2 surfaces as they mate determine this. To illustrate this if you take a large heavy cone and place either end of the cone on the same surface its requires the same lateral force to move the cone regardless if I place the small end or the large end of the cone on the surface. Most people don’t seem to know this. Don’t take my word. Check it out for yourself.
    Now on to lateral and camber forces. When you sharply turn a car camber forces come into play the same as a motorcycle and for the same reason. The front wheels of the car lean from the compression of the front springs. Most cars run radial tires and they behave the same weather on a car or bike. The car adds a lot more force because of the weight. The side walls give and bulge to keep as much of the tread flat on the ground. as possible. On a heavy cruiser you cannot lean enough to get the tire on the sidewall.
    A talker instead of a rider will get on a bike with a ct and he will hate it and be scared to death. A seasoned rider will notice slight differences that will become normal in short order and he will love it. Most darksiders are seasoned riders and have earned the rights to make up their own mind. More people believe themselves to be seasoned but they are only fooling themselves. These are the people you will read about in the obits. It had nothing to do with their choice tires and their opinions.

  15. This Ron fella is very contentious, isn’t he? Ron… it is established that you don’t like the ct on a mc idea at all. You don’t have to resort to calling others opinions stupid or other derogatory names. Just learn to accept that yours is not the only opinion.

  16. Car tire for a BMW K1200RS. My 2003 model has a 5.5″ wide 17″ wheel running a 180/55r17 MC tire. I bought a 175/55r17 tire, an Achilles 88V ATR-K Economist model. Current Michelin Road 3’s almost worn out and am soon to fit the new flat tire. Bought K1200RS lug nuts and spacers in 55mm, 60mm, and 63mm lengths in case I need additional offset. Gonna be a close fit but I’m not too worried. Just go onto eBay and search for 175/55r17 and tires will pop up. I drag a Hannigan Sidecar alongside the BMW. If you buy a chair be sure to buy electric camber adjust also. Why didn’t I do that before? Had one sidecar before in the 52 years since my first motorcycle. Took two men and a boy to steer it around curves compared to this one with “EZ-Steer” and electric camber adjust.

  17. I take “seasoned rider” with a grain of salt as much as those who go on about “scraping” You won’t scrape as much if you learn how to counter steer properly. I see MANY “seasoned riders” who with all their experience do not know how to counter steer properly. I’ll be the first to admit I didn’t get it right away and took time to understand the concept and the light bulb went off and I’m a much better rider for it. If you find yourself scraping often on a cruiser, then you are probably not counter steering and I recommend learning how to do this.

    • Not as dumb as Tony’s post, but still dumb. Different cruisers scrape at different levels of lean. Read any professional review for a Vulcan 900 and they will mention how they were scraping the boards really easily in the turns. Do those guys not know how to counter steer either?

      Seriously people, stop thinking that your experience on your bike speaks for everyone and every bike. It just makes you look interminably stupid.

  18. Considering a car tire here simply because I work 71 miles away and put my own tires on. I have money for MC tires, and I mount my own because bike shops aren’t open at night or Sunday. Florida roads are in decent shape. I do 5 or 6 rear tires a year. I never corner like the track photos that tire manufacturers show, and I’m sure they’ll never recommend not using their tires, just like the stealership says that they should always mount all tires. I’m putting a CT on my VTX 1300 today, with enough tread left to switch back if I don’t like it. I modify everything I have, my guitar, computer, septic tank, everything, with varying results, and I don’t drink Kool-Aid. I’ll post back.

    • OK, it’s 10,000 miles later. The CT took some getting used to. In fact I told other riders that I’ll never do another CT, but now I’ve changed my mind, I’ll always do CTs on the rear. It looks like I’m about half-way through it, and it’s wearing mostly in the center, just like the MTs did.

      Handling: It’s weird at first, feels like the back end is sliding out when you turn, but I found the explanation for that, something I never thought about. You know that smaller tires essentially change the gear ratio, the bike goes slower at the same engine RPM. Well, the circumference is smaller on the edge of a rounded tire, so when you turn, the bike naturally slows down. The physics is undeniable. Flatter tires just don’t exhibit as much of this effect, and to someone who’s ridden tens of thousands of miles on a rounder tire, of course it gonna feel weird.

      I haven’t experienced anything like the wobbling or other handling nightmares on the other posts, and the VTX1300C is not exactly a huge bike, either. I never take both hands off the bars, and I’m not going to start just to see if I crash. It DOES handle differently, cracks in the road – uneven pavement and all that, but it’s not out of control. It’s just different. Now, after 10,000 miles, it’s not different anymore, it’s the new normal.

      Oh yeah, no special tire, I got a Dunlop 205/70/15 at Wal-Mart, but setting the bead was tough, really tough. I was nearing 90psi when my son and I finally got it all the way, using plenty of foul language. I found a bike shop that’ll mount and balance a CT for $30 if you take the wheel off the bike, so I’ll let them do it next time.

      Just my opinion here, do what you want. Cruise on.

  19. I have been running a passenger car tire on the rear of my Victory Vision 8Ball for two years and 15000 miles. I live in the western North Carolina mountains and visit the Blue Ridge Parkway daily. We use it to get to the more challenging twisties in the area. In every aspect of tire performance the passenger tire has worked better than the E3,s that came on the bike. I can not get the pass. Car tire to slide in any road conditions. It is more comfortable, longer lasting, runs cooler, etc. etc. Oh, and by the way, my experience is 49 years on 43 different motorcycles that I have owned. I will not be returning to mc tires for the rear of my bike.

  20. It seems that both sides of the darkside debate have the same problem. Just because your bike reacted a certain way to a car tire, either positively or negatively, then clearly ALL motorcycles must react the exact same way. This is complete rubbish. Not only will different bikes react differently to car tires, different riders will react differently to the same car tire being put on the same bike. To each their own.

    Having that that, however, the pencil eraser analogy is one of the dumbest things I’ve seen in a long time, and the writer should be banned from ever owning a computer ever again.

  21. 2007 stratoliner with goodyear eagle performance tire 215/60-17…..been riding for 30 years… my license when i turned 16……love the car tire on back and use a metzler steel belted on the front. I love the interstate and will burn any cruisers in the twisties… By the way the car tire raises the rear of the bike and helps from scraping the floorboards or pipes better. Just feels different but very sticky and smooth…..more safe in wet or gravel and sand. And brakes way better. My experience ! My opinion !

  22. Hi my name is Ted Johnson I live in Spain my bike is a Hond a 1100 gold wing interstate it is 36 years old when I reached 65 years of age I decide a
    side car was my best option if I was going to carry on riding I have leading link forks on the front with an Avon side car tyre I left the original motorcycle tyre on the rear it has worn quite well but when cornering the outfit seems to roll| I think the tyre wall is to flexible for an outfit so I am thinking car tyre
    Is the rime angle of the bike wheel the same as the rim angle of a car wheel or is it likely to roll of under side pressure

  23. I have a 650 Suzuki Burgman Scooter, last year I put a rear car tire on it and I love it wouldn’t go back to a motorcycle tire whatsoever on the back

  24. Good Day Folks,

    Can anyone kindly advise me CT makes and sizes that will fit Harley Ultra Classic 2012 fitted with a sidecar?

    Current sizes stock 130/80-17 front and 180/65- 16

    Australian,, mostly dry riding,,,,,,,but I am an old bloke and safe in the wet weather.

    email ;



  25. could someone suggest a run flat tire for my 2002 ultra classic. would be much appreciated as i would like to try one out.

  26. I’ve heard this same argument over and over from those who have no practical experience with a car tire. I love to use this example that shows a couple “experts” telling me why I couldn’t do their course. I took an experienced riders course a few years ago and when we got out to start the riding asked “Is that a car tire?!?” The instructors heard it, came over, looked it over and said “You’ll never be able to do this course with that tire.” I just laughed and said “Watch me.” They told me if I couldn’t do it I wouldn’t get my money back and I just grinned again.

    Long story short, an hour later I was riding their course, dragging my floorboards with no problems while they stood their shaking their heads. After class, a bunch of us were going to eat and the instructors were going with, As I got on the entrance ramp to the interstate, they were right behind me when I hammered it into the corner to get ahead of oncoming traffic. When we got to the restaurant, they both said they couldn’t believe how much of a contact patch I had with that tire. I run a Hancook Ventus V2 concept 2 which has very rounded edges and a good flexible set of sidewalls.

  27. 50 years of riding starting out at age 9 so I think I have earned the right to my opinion. I use to race flat track and I hill climbed in my youth also. Never would I tell someone to put a ct on their bike but you know what I have a Wing that has one as well as a Nomad that I did the same with. I never even considered that it was about price, actually I spent more on my rear ct then I would on 2 sets of Dunlops, Metzlers oor Avons. For me it is that I feel a better grip with it on curves , switchbacks and straightaways I have also noticed about 5 mpg per gallon increase in mileage. My conclusion is that at least on most cruisers it will work (not all by any means) tire choice, bike, air pressure and many other factors come into play. They can be a bitch to get them to seat but once you get that worked out your all good. I suggest that if you do try it put about 500 miles on it before you make a decision. I do that even on bt’s I buy for my other toys. If I dont like a tire ct,or bt I will pull it off and try something else out, be damned about the money. I dont know many people that buy used bt’s or for that matter 1 ct. It’s a choice and it’s your choice not going to argue with you I just know what I know, but I have only been riding for 50 years so what would I know. My first street bike was a custom built chopper I made with my dad and guess what it had a car tire on it and back then that was a much better choice then the crap bt’s they had to offer.

    • I too have been riding for over 50 years and have owned and ridden 52 different bikes, and finally on number 42, my 11 Vic Vision, I put on a ct. Truely amazing performance over mc tires. I noted better performance in every aspect . Those of us willing to open our minds and embrace the so called radical ideas will enjoy the benefits. My one million miles tell me I,m right.

      • Been riding since I was 17. Literally dozens of bikes and hundreds of thousands of miles. My last two bikes have been CT and I can’t believe the increase in performance. More grip in the curves, better wet handling and the thing that surprised me the most, rear braking is actually a thing now. It doesn’t break loose as soon as you hit the rear pedal. The rear tire actually grips and helps stop the bike faster.
        The extra miles and lower cost are just icing on the cake. I’d pay MORE for a CT if I had to.

  28. A car tire won’t fit on my bike, but my husband has been riding his Honda VTX 1800 with a car tire on the rear for about 8-9 years now, and has covered about 100,000 miles with them (bought the bike in 2002 and will turn 200,000 miles this year). He loves it and would never go back to a motorcycle tire on the rear. I have no idea how many car tires he’s gone through in those 8-9 years, but he is sold on them. I mention the mileage on his bike so that it can be easily seen that he didn’t just start trying it out. He goes on multiple long distance bike trips every year, and he also rides his bike to work every day – all year long. Never had any problems.

  29. I see this discussion is still alive 🙂 Yesterday I have put a CT on my Victory Cross Country Tour. I´ve read a lot. I have some 100.000 miles on different motorcycles, mostly heavy cruiser or touring bikes. CT makes sense for this type of bikes. But many factors is affecting this. Also a tire pressure. I have just started and the biggest surprise is, that there is SO SMALL difference between the MT and CT … wouldn´t believe it. But as I say, I will test it and will tell you my real opinion. If the experinece will be bad, I will go back to MT. But if you use a logic without a prejudices, you must find out (even without trying) there shouldn´t be any serious problems in using CT on motorbike. And the experience shows the same.
    I wish that there would be some really exact and serious and scientific test, which would somehow exactly “measure” the parameters etc… but it s probably only a dream 🙂 Until then, people will discuss, and that´s all 🙂 Best regards to you guys and ladies from Europe! Martin

  30. Early 70s we ran car tires on harleys and norton’s.
    Couldn’t do it on triumphs as the chain was too close to run a fat tire.
    We ran low air pressure as those choppers had no shocks in the rear.
    They ran fine,if you remember the old goodyear eagle tires were a very hard tire.lasted a long time,
    The avon safety mileage was another hard compound tire.
    Then manufactures came out with this soft compound tire,no tread,to speak of,
    Great for a dry clean pavement,scary in the rain.
    I have bought a new indian,it has a car tire ,the first thing I put on it after getting caught in the rain.

  31. Seems to me that all this debate shows one huge obvious fact:
    Heavyweight cruisers and touring bikes seem to be getting on reasonably well with automotive tires..Fine and good.
    However, for older and modern superbikes and sport touring bikes
    it’s motorcycle tires PERIOD.
    One poster mentioned Moto GP….
    the same could be said to apply to WERA, AMA CCS, the WMRRA and any other racing organization.

    So let’s be rational realistic and covil now….enjoy the summer.

    • Well said. If a car tire was better than a motorcycle tire for racing, I assure you they would swtich in an instant… If they were allowed.

      Racing has little to do with real life riding where most people wear out their race tires with a flat spot down the middle and 80 percent tread left on the outter edges.

      On a bike that rides straight for hours and hours touring, Why would you use the same tire as someone who is in a curve half the time?

  32. I changed to a car tire recently – a Yokohama run flat. Personally – I don’t like it for the simple fact it wants to follow the ruts….and in SE AZ we have a lot of those roads. I also tried different air pressures. I was looking forward to a rear tire that I could ride for a few years – but going back to a MC tire for personal riding reasons. To each his own…but at least I can say that I have tried a car tire! Safe riding to you all.

  33. I’ve been riding since 1966-1967 and don’t see what all you professionals think you are passing on to the M/C world besides how to piss and moan on your PC. I’d be willing to bet that most of you ride electric bicycles. You all sound like a bunch of old cackling hens. Run what the hell you want to.

  34. I have read every response on this thread and have tallied the overall responses. There are many many more riders who like using CTs than those that have used them and gone back to MTs. There are many many MT users that have never used a CT and say they don’t like them because of their perceived physical and handling differences or other biased reasons for not ever considering using them in heavy weight cruisers.
    That about sums it up. So, I say if you haven’t tried it in a heavy weight motorcycle and done the research for the correct type of tire and pressures when you have used them: then those are just opinions with no real life or incorrect experiences. What I would like to see are these so called independent motorcycle (now internet) rags do real life long term road and track CT experiments without spouting a bunch of “physics” and safety AMA and Tire manufacturer reasons you shouldn’t even consider it. To my knowledge that has never been done: why? do $$$$ talk that much? Seems so.

  35. This is such a fun topic.
    I don’t care what you ride, or what tire you put on it.
    I have had many bikes with Car tires on them, and they rode smoother and had better traction than motorcycle tires. I leave the motorcycle tire on until it wears out, then replace it with a car tire. These were all cruiser bikes.

    I have sports bikes, and they all keep the best motorcycle tires I can buy on them. Why? They are different bikes used differently.

    Would a car tire be as good or better? I don’t know, I never tried. But I wouldn’t blame someone for trying. Also, if they did it and wholeheartedly loved it, I may consider it.

    I’ve seen videos of bikes on tracks with car tires …they look nothing like the pencil eraser example. It’s just not how life works. Even motorcycles on tracks typically reduce the pressure of the tire to act more like a car tire to get more patch on the asphalt.

    I chuckle at all the self-important posters that think their skill is so much higher than others that they need special tires so they can lean more… Good riders lean less, not more. But some judge others by “chicken strips” and think because they ride the sidewalls of their MC tires they are experts. Keep believing it and invest in thick race suits and new fairings.


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