ver since the checkered flag fell on Spain’s Valencia Grand Prix last November, racing fans around the world have been eagerly awaiting the 2005 MotoGP season. Following a remarkable 2004 campaign in which Valentino Rossi stunned skeptics by winning the World Championship in his first year on a Yamaha, attention immediately turned to the question of whether he could repeat the feat. Or would the competition turn up the heat and prevent “The Doctor” from claiming a fifth consecutive title?
     But probably nowhere has the off-season anticipation been greater than in the U.S., which will host a Grand Prix for the first time since 1994, at California’s Laguna Seca circuit. Clearly Americans have been starved for MotoGP action in their own backyard; advance ticket sales ensure that the event will be a sellout.
     For Michelin, the 2005 MotoGP season presents another challenge: to continue its dominance of the world’s most prestigious and demanding form of motorcycle racing. Last year the tire maker earned its 13th consecutive Grand Prix world championship, winning 14 of 16 races and claiming 44 of a possible 48 podium positions, despite determined opposition from rival tire brands.
     Three races into the 2005 season, it appeared as if Michelin was still the top dog in MotoGP tire technology. Rossi (Yamaha-Michelin) took the checkered flag in the opener at Jerez, Spain, with a daring last-corner pass of Sete Gibernau (Honda-Michelin). At Estoril, Portugal, Alex Barros (Honda-Michelin) capitalized on Gibernau’s misfortune in changing weather conditions to grab the win. In rainy Shanghai at the inaugural Chinese Grand Prix, Rossi gave Michelin its 325th victory since the company first entered the premier class of GP racing in 1976. And at the French Grand Prix, Rossi pulled out another close win over Gibernau.

 



     Building tires for 240-horsepower race bikes obviously takes some serious technology. “We have worked very hard since the advent of MotoGP to give riders maximum traction to cope with the bikes’ massive power outputs,” according to Nicolas Goubert, director of motorcycle competition for Michelin. “We’ve been very successful in this, so this year our priority has been to improve sidegrip. This will also help riders, because they can now use more corner speed, which allows them to get through corners faster.”
     Yamaha MotoGP star Colin Edwards believes that effort has paid off. “Michelin has made some phenomenal progress over the winter, working to give us more contact patch,” said the two-time World Superbike champion. “The front has come on some, just like the rear. It seems like we’ve got a load more sidegrip this year.”
Fortunately you don’t have to be a factory MotoGP star to benefit from Michelin racing development. “The relationship between racing tires and high-performance street tires is much closer than most people think,” said Bernard Jarrousse, motorcycle product manager for Michelin North America. He noted that the Michelin Power Race and Pilot Power tires both incorporate technology that is currently in use in MotoGP racing, providing “civilian” riders with previously unheard-of levels of grip and handling.
     The Power Race is positioned as an ultrahigh-performance tire for track days and racing use. The tire’s revolutionary Two-Compound Technology (2CT) follows in the tracks of other street-tire innovations that Michelin has pioneered, including radial technology in 1987 and silica-charged rubber compounds in 1999.
     With the Power Race, for the first time street riders can mount a tire that uses different compounds in the center and on the shoulders of the tread, achieving optimal performance while adapting to the constantly changing forces acting on a tire’s contact patch.
     Taking a cue from MotoGP tires, the Power Race design divides the tread into two zones, each of which uses a rubber mix suited to its specific performance requirements.
     Multi-compound technology was inspired by a simple observation: when a motorcycle is upright, only the center of the tread is in contact with the ground, and when it leans, it rides on the tread shoulder. The center tread compound of the Michelin Power Race is hard enough to withstand the severe forces of rapid acceleration or hard braking, while the tread shoulders use a softer compound, to match the reduced stresses experienced at full lean, when speeds are lower and there’s little or no acceleration. The softer compound in turn provides better grip while cornering.
     Michelin has sought to meet each rider’s specific needs by offering not just one version of the Power Race, but three: Medium, Medium Soft and Soft. The three differ both in the compounds used, and in the tread surface area devoted to each of the compounds.
     Just like MotoGP racers, riders can now choose exactly the right combination of compounds to suit their personal riding styles. The Michelin Power Race family comprises no less than seven rubber compounds and six tires (three front and three rear) to cover the broadest possible range of street and track applications.


     Why seven compounds? The front and rear tires of a motorcycle are subject to very different forces. The front tire is generally under less strain than the rear and therefore can use a softer tread, for grip, precise steering and feedback. The rear tire uses a harder compound, since it has to transfer engine torque to the ground, and is therefore prone to faster wear.
     The Soft versions (front and rear) of the Power Race employ a single soft compound to give maximum grip on every part of the tread in contact with the ground. These tires heat up quickly across the entire tread width and are recommended for qualifying sessions and races that are run in cooler conditions.
     With so many options available, Michelin has gone the extra mile to help riders choose Power Race tires, publishing a CD-based tire guide that draws upon the company’s extensive racing experience. The interactive, user-friendly guide makes straightforward recommendations based on five criteria: temperature, weather conditions, type of track or road, use and engine displacement. Call Michelin at (800) 346-4098 to request the Power Race tire guide on CD, or visit www.michelin-us.com.


As shown in highlighted areas, Michelin Two Compound Technology is used in all medium-compound Power Race tires and in the medium soft-compound front (left).

     Besides multi-compound technology, the Power Race copies a number of other features found in Michelin MotoGP tires. Power Race tires are made from a rubber formula specifically developed for the racetrack, known as C-RAO (Compounds-RAcing Optimization). It’s a combination of three 100% synthetic components identical to those used in MotoGP tires during the 2004 season: proprietary Michelin Racing Synthetic Elastomers (MRSE) and two additives, Macro-Molecular Compound (MMC) and High-Technology Synthetic Compound (HTSC).
     In addition, virtually the entire Power Race range is manufactured using Michelin’s highly secretive C3M process, the same used to make MotoGP tires. Michelin won’t say much about C3M (which stands for carcasse, monofil, moulage et mechanique), but they will concede that the process consists of a single step, instead of the seven used in conventional tire production.


Test riders have achieved lean angles exceeding 50 degrees with the Michelin Pilot Power–remarkable performance for a street tire.

     With C3M, Michelin can make the tire on a solid insert mold, so that the raw tire has the same shape as a cured one, which isn’t the case in traditional manufacturing. This means that precise quantities of tread compound can be applied with pinpoint accuracy–a feature of critical importance in the manufacture of a multi-compound tire like the Power Race.
     Capitalizing on all this technology, Michelin has produced a tire that is not only multi-compound, but also one of the lightest front tires on the market (8.5 pounds on average). This minimizes rotational inertia, for better acceleration and braking performance. What’s more, the combined weight of front and rear tires is lighter than any other DOT racing tire (21.4 pounds on average), minimizing unsprung, rotating mass.
     It already looks like Michelin has a winner on its hands. The Power Race won Roadracing World’s on-track shootout test of DOT race tires, featured in the magazine’s June 2005 issue. Suggested retail for the Power Race ranges from $377 to $526 per set, depending on sizes and compounds.


The Power Race and Pilot Power are positioned at the top of the Michelin line of performance tires.



     Michelin MotoGP technology is also available to non-racers in the form of the Pilot Power tire. Aimed at performance-minded sportbike riders and especially those who take part in track days, the Pilot Power’s rubber mix incorporates synthetic elastomers that were originally developed for MotoGP racing. This C-RAO rubber gives the Pilot Power incredible grip, and especially quick warm-up time, while delivering mileage comparable to that of the highly regarded Pilot Sport tire, which it supersedes.
     The Pilot Power uses a semi-slick tread pattern with a void area (land-sea ratio) of just 13.28 percent on the front tire and a mere 11.58 percent on the rear. A lower void ratio promotes greater tread rigidity, which minimizes tire deformation and enhances grip in aggressive riding situations.
     The stable tread pattern also helps extend tread life, allowing the Pilot Power to employ the softest rubber compound of any comparable performance tire, without compromising mileage. And the rubber mix remains soft at cooler temperatures, providing excellent adhesion even at the start of a ride.
     Despite its minimalist tread design, the Pilot Power is more than just a dry-weather tire. On the Michelin test track at Ladoux, France, riders were able to lean a Pilot Power-equipped bike to an amazing 41.9 degrees in corners–in full wet conditions! In the dry, they achieved an equally remarkable 50.6-degree lean angle.
     Aiding this cornering proficiency is a new casing profile that has also been inspired by MotoGP development. The Pilot Power’s more pointed profile, compared to the Pilot Sport, increases the size of the contact patch at full lean for improved feedback and handling.
     But even with all this technology at your disposal, the question remains: How well do they work? Steve Atlas, a championship-winning racer and an editor for Roadracing World magazine, tried the Pilot Power on the road course at Las Vegas Motor Speedway and had this to say: “…the Pilot Power just plain works. Outright grip was great and the tire heated up quickly. And by quickly I mean dragging a knee in the first half-a-lap, starting from cold tires, in mid-60 degree weather…The front Pilot Power had feel and grip rivaling that of any of the latest DOT-labeled race rubber, and turned almost telepathically.”
     Later, after the Pilot Power served as the control tire in a shootout track test of 1000cc sportbikes, Atlas commented, “These are the best street tires I’ve ever ridden in my life.” Suggested retail for the Pilot Power ranges from $305 to $355 per set.

For more information see:
www.michelin.com


Parts Magazine
Volume 12 #6


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