Looking for a new tire? There’s certainly no shortage of good rubber available these days for the tire shopper. If you’re happy with your tires’ mileage and performance, you can always buy new copies of the original equipment tires for your bike. Or, like many riders, you can look for something that handles sharper, goes farther, or sticks better to rain-slick roads. Just be sure to check the owner’s manual for your motorcycle to get the right size and type. The OE tread for an older machine may have been discontinued, but a quick call to a tire maker should help you line up a new, equivalent model. In any case, our buyer’s guide is a good place to start your search for touring and sport-touring tires. But don’t turn the page yet if you ride a cruiser—many of the tires listed here are suited to your machine as well.
First, some news. Things have changed in the tire world since our last buyer’s guide in the May 2002 issue. Every year brings more powerful motorcycles—Kawasaki claims nearly 200 ponies for its new ZX-14—requiring new levels of tire performance. With near-warp speeds in sight, the powers that be (the International Organization for Standards, or ISO) have to keep pace with tire speed ratings. A Z in a tire’s size description, though it’s not a speed rating as such, has always meant that the tire is good for speeds over 149 mph. Now W and Y, representing max sustained speeds of 168 and 186 mph, respectively, are also showing up in tire load ratings. Many of the tires reviewed here are W rated, other ratings we mention are H for up to 130 mph and V for up to 149 mph. The prudish will be pleased that there are no X-rated tires.
The other code to look for is the load range, a number that denotes a tire’s weight rating in pounds. For example, my Honda VFR750F wears a 120/70-ZR17 up front. The Michelin Pilot Road in that size has a load rating of 58, which is good for 520 pounds. Add that to the 783 pounds for the 72-rated rear 170/60-ZR17 and you can see that a set of Pilot Roads will safely carry the VFR, along with me, my riding gear and a good-sized refrigerator. A solo sport-tourist can probably ignore load ratings without peril, but riders carrying a passenger on a full-dress touring rig should do the math.
Tires may look uncomplicated, but those black, circular concoctions of steel, rubber and fiber belie an inner complexity that takes a product team thousands of hours to perfect. And once you make a great tire, the job turns to designing the next one. A cross-pollinated team of experts is involved with each new model brought to market. We’ve outlined the development of Dunlop’s Elite 3 touring tire to give you an idea of the effort involved in producing a tread for your two-wheeler.
New and Improved
What to build next? Market research will tell you what’s selling, which new bikes require a new level of tire, and how well your current model is doing. Then it’s up to product specialists to set the design objectives for the new tire. According to Dunlop Product Manager Mike Manning, Dunlop divides tire performance into sub-categories, like wet-surface braking, and sets quantitative goals for each of them based on their own tires and competitors’ offerings. A fly on Dunlop’s wall in Buffalo, New York, might hear something like, “Let’s give this thing a 15 percent larger footprint at a 30-degree lean angle,” or, “Man, I’ve eaten so many chicken wings I’m starting to cluck; let’s have pizza today.”
When generating new tire requirements, there’s no substitute for talking to riders to get the skinny on what works, what doesn’t, and how they use your product. Dunlop performed tire checks—weighing bikes, looking at wear patterns and checking air pressure—on thousands of bikes and interviewed their riders while researching a new model to supplant their popular K491 Elite II. The team went home with reams of data to plug into their tire development equation. Their final overall goals ran the gamut from excellent wet-weather performance to consistent handling on irregular surfaces like tar strips and rain grooves, to building a wide custom tire. Manning told me that a major development obstacle is vehicle handling demands, so with a nod to big-bike handling improvements, they added a radial design to the Elite 3 family.
The engineers got their marching orders and disappeared into their labs. Once the prototypes were ready, it was time to test. Standard tire tests include running the tires on a drum at high speeds, abusing the carcass until it gives up (and analyzing each failure), and examining the tire’s footprint for shape and size. The prototypes aren’t the only tires running this gauntlet—Dunlop also tests their own legacy tires, both new and used, and a range of products from their competitors. If all looks good with the prototype, they up the ante and pack it off to their joint venture partner’s facility, the Goodyear Akron Technical Center.
Remember all that user data they collected from the rally riders? Much of it goes into creating a “drive file” for a special wear machine at the center that runs the tires to their limits through cycles of driving, braking, tilt and load that are gleaned from interviews with riders like you. Hundreds of hours of mechanical and riding tests have proven the machine’s ability to simulate real-world riding, making it a valuable asset for tire development.
Still, there’s no place like the pavement to test new rubber. A tire candidate’s next stops are Dunlop’s Huntsville Proving Ground and other closed courses, where they’re tested for dry- and wet-surface handling and are ridden at high speed on racing courses and ovals. If a tire doesn’t fail on the track, it’s unlikely to let you down
in the middle of the Mojave or sailing across Nebraska on Interstate 80. Track testing uses the same kind of on-bike telemetry that race teams employ to transmit data on handling characteristics like fork travel and handlebar movement to a computer on the sidelines. Want to know how a particular configuration works on rain grooves, or corners on wet pavement? Does the front end shimmy ever so slightly on deceleration? Check the data.
Development becomes a cycle of feeding test data back to the engineers, tweaking the design and testing new prototypes. Dunlop cut more than a dozen different tread patterns into fresh rubber and tested many of those on wet surfaces. After more than 8,000 hours in the lab and 2,500 man-hours of motorcycle testing, a new tire is born—a complete integration of carcass, rubber compound, profile and tread pattern meeting the design objectives established years before is waiting to be shipped to a dealer near you. But not before several first-run units from the warehouse are drum tested, cut up, X-rayed and analyzed to validate the production process. Finally, the first lot leaves the plant. Glasses clink, engineers breathe a sigh of relief, and management walks in with the next assignment. Everyone feels good about making a successful new tire, but the real beneficiaries are riders like us, who get a safer, better handling, higher mileage tire. I propose a toast to tire teams everywhere!
Avon, P.O. Box 5112, Edmonds, Washington 98036; www.avonmotorcycle.com
Avon uses an alphabet’s worth of manufacturing processes and design elements in its Azaro ST sport-touring tires. SBC (Spiral and Belted Carcass) builds a strong casing, A-VBD (Advanced Variable Belt Density) strengthens the center for stability and increased mileage while allowing shoulder flexibility, EAF (Enhanced Aqua Flow) tread gives excellent water dispersal, and ATAC (Advanced Tread Arc) varies the tread profile for handling and stability gains. The W-rated Azaros also use a silica-enhanced tread rubber for their extra deep tread. They’re sized to fit a wide selection of sporting hardware.
Avon’s Venom R serves up a stout and stable five-ply casing for big touring rigs and heavy cruisers. Two of the plies are Aramid fiber to restrain tire growth at speed, increasing the miles per tire. Low rolling resistance brings cooler temps in the long haul, also extending mileage. Avon offers four H-rated Rs and a pair with W ratings. A rounded profile gives neutral steering characteristics, while the large block tread pattern hinders cupping and keeps tire noise to a minimum.
Bridgestone/Firestone, P.O. Box 140990, Nashville, Tennessee 37214; www.motorcycle-karttires.com
Bridgestone’s Battlax BT-020 sport-touring radial uses its mono-spiral belt design—wrapping a single strand of fiber around the casing’s circumference—to eliminate the weight and weaknesses of overlapping plies and to improve shock absorption and high-speed stability. Their Comprehensive Tire Design Method provides 3D simulations to optimize performance at every lean angle. Capped with Bridgestone’s silica-rich tread rubber, the BT-020 boasts improved wet road grip and traction on tap without a lengthy warm-up. These W-rated sport tourers are available in a wide range of sizes, plus many OE-specific applications.
Designed for heavyweight and touring cruisers, Bridgestone’s G850 and G851 Exedra radials split their personality between going long and going strong. The G850 rear tire uses a mono-spiral belt like the BT-020, while both hoops get a high-silica tread for inclement weather performance and carry a W speed rating. Bridgestone builds Exedras in several big sizes for the biggest cruisers.
Continental, P.O. Box 105, New Albany, Ohio 43054; www.conti-moto.com
The ContiMilestone is Continental’s offering for big cruisers and tourers. It’s a “breaker/belted” design, using both nylon and rayon belts to build up the casing and give a stable, non-jarring ride. An absorption pad in the front tire cushions impacts even further. Continental uses its proprietary Activated Silica Compound to significantly increase wet road performance while still delivering excellent mileage. Their tread pattern inhibits groove tracking and handles rough roads with ease. All Milestones are H-rated and approved for tube or tubeless use. There are sizes aplenty to fit metric cruisers, Harleys and touring bikes.
Conti calls its RoadAttack a “sport mileage radial” because it combines the traction of a sport tire with the mileage of a sport-touring skin. A multicurve profile yields handling benefits, while silica-enhanced tread rubber and a larger contact patch generated by Conti’s Dynamic Footprint Technology boost traction on all surfaces. The underlying structure is a zero-degree steel belt that ensures a stable and comfortable ride. All RoadAttacks are W-rated and sized to fit all popular sport-touring machines.
Dunlop, P.O. Box 1109, Buffalo, New York 14240-1109; www.dunlopmotorcycle.com
Dunlop’s newest heavyweight tire is the Elite 3 (E3), which it build in radial and bias-ply models to cover touring bikes and cruisers both old and new. Conceived as a significant upgrade over its popular K491 Elite II, the new Dunlops boast higher load capacity, improved stability on irregular surfaces, better grip on wet and dry roads, and excellent mileage. A sport-derived profile sharpens up handling as well. E3 sizes include a V-rated 250/40-R18 custom wide tire; the remaining four radial and eight bias-ply sizes are H-rated.
If your touring is of the sporty variety, Dunlop’s D220s are at the traveling end of its sport radial lineup. W-rated for extended autobahn runs, the D220s use Dunlop’s jointless band construction, a continuous Aramid belt wound circumferentially, to limit tire growth and promote high-speed stability. Dunlop’s carcass/tread compound duo delivers a long-lasting tire, while the tread pattern elevates performance on wet surfaces. Eight sizes cover a wide range of sport tourers and several metric cruisers.
The premier sport-touring tire from IRC (Inoue Rubber Company, in case you’re wondering) is the SP-11. The front tire features Belt Cord Density Control construction, a lower density of belt cord at the sides to improve cornering and a higher density in the center to promote stability. Beneath that are two cross plies and a radial ply; coating the sides is a new, higher grip tread rubber. The rear gets a zero-degree belt of Aramid fiber and a new silica tread compound for better grip in all conditions.
IRC makes the W-rated SP-11 in several sizes to fit larger sporting machines. IRC’s RX01 is built to fit sporty bikes requiring a bias-ply tread. Designed to achieve a balance between grip and durability, it uses a stout casing to assure steadiness on the straightaways and an innovative tread pattern to improve wet-weather grip. It’s H-rated and available in four front and three rear sizes.
Kenda’s K657 Challenger carries a hefty six-ply rating and stiff sidewalls, all the better to help it support heavy loads. Rated as tubeless, but approved for tube use, the H-rated, bias-ply sport-touring tire features a tread pattern designed to disperse water on wet roads, and a stiff sidewall to promote stable handling. Kenda’s new tread compound is designed for a vigorous touring pace. Challengers come in a wide variety of 90-series sizes.
The K673 Kruz is Kenda’s tire for large cruiser/touring bikes. It sports an all-weather tread pattern plus a new tread compound that increases tire mileage and keeps it hooked up on wet roads. Exclusive to the Kruz line, a new 3+2 casing design (three full bead-to-bead plies and two more beneath the tread) is used front and rear to reduce tread movement and maximize both mileage and high-speed stability. This H-rated, tubeless bias-ply comes in an array of sizes to fit both metric cruisers and Harleys.
Kenda, 7095 Americana Parkway, Reynoldsburg, Ohio 43068; www.kendausa.com
Metzeler’s venerable ME880 Marathon line of tires for touring rigs and big cruisers just got bigger—a 260/40-VR18 size has been added to its XXL sizes. It’s meant to slip into place where a 250 width has been spinning, but check with your dealer for specifics. Metzeler builds machine-specific carcasses, so some Marathons are radials while others are bias ply. The XXL sizes feature zero-degree belts to control tire growth at speed and allow close tire-to-fender tolerances. Marathons are available in more than 50 sizes, so you’re sure to find one for your heavy hauler.
Metzeler’s premier sport-touring skin is the Roadtec Z6, a radial tire with a stabilizing zero-degree steel belt. Designed using Contour Modeling Technology to generate tire profiles that give optimal handling at every lean angle, the W-rated Z6 also features a new sidewall structure to soak up bumps and individual carcass designed for motorcycles on either side of 500 pounds. CAD-generated tread patterns boost the Roadtec’s wet-weather traction, while a new tread compound augments grip on dry surfaces. The entire design package is integrated to maximize mileage and maintain performance for the life of the tire.
Metzeler, 100 Pirelli Drive, Rome, Georgia 30161; www.us.metzelermoto.com
Michelin, P.O. Box 19001, Greenville, South Carolina 29602; www.michelin-us.com
The most specialized tire here has to be the H-rated Michelin Pilot GT, built exclusively for the Honda GL 1500. Michelin chose a cross-ply design to maximize load capacity and mileage. There are four plies on the front tire, while the rear has three cross plies and two crown plies. Michelin’s high-tech tread rubber includes its proprietary High Quality Molecular Compound plasticizer. The front tread also gets High Tech Synthetic Compound, a plasticizer created for MotoGP bikes, plus a tapered tread profile for precise cornering and better low-speed handling.
Michelin’s Pilot Road sport-touring radial can’t be all things to all riders, but its high-grip silica tread compound, neutral handling and smooth ride give it appeal to a wide range of motorcyclists. Two plies laid at 75 degrees topped with a zero-degree crown ply produce consistent handling over a wide range of loads and wear conditions, plus the durability to go the distance. Michelin builds the Pilot Road in six popular sizes each for front and rear, and a W speed rating means peace of mind on long, fast transits.
Pirelli, 100 Pirelli Drive, Rome, Georgia 30161; www.us.pirelli.com
Targeted at the metric cruiser market, Pirelli’s MT66 “Route” bias-ply tires use four plies of nylon material in the carcass. Their low weight keeps the ride comfortable by soaking up bumps and not overloading the suspension with excess mass. H-rated for long, hard runs down the Mother Road, the MT66s are designed to improve handling, extend mileage and hold the road in wet or dry conditions. Raised black letters add a touch of style to this durable and affordable tire.
The Strada is the tamest of Pirelli’s three levels of Diablo sport tires, giving the sport-tourist a spirited combination of grip and stability without sacrificing mileage and all-weather performance. These W-rated radials utilize a zero-degree belt to enhance stability and paired front/rear profiles to create the best footprint for maximum traction. An improved, silica-rich tread compound warms quickly and sticks well to wet and cold surfaces. The three front and four rear sizes will shoe many sport-touring machines.