Michelin Pilot Sport AS - Contact Patch

Laurens, South Carolina-Michelin has developed more than its fair share of innovations over the years. The company's biggest claim to fame, of course, is the invention and subsequent commercialization of the radial tire, but there have been many other important ideas where the French-based tire maker has been ahead of the curve.

In the performance tire area, the 1960s brought the groundbreaking folded steel-belt XWX line for cars from Ferrari, Lamborghini and Porsche. The 1970s saw the technically brilliant but commercially flawed TRX line with its special rim design. This setback put Michelin a bit behind the curve in the performance market during he early 1980s, but by the end of that decade and through the 1990s the company came back strongly with a variety of high-performance summer, winter and all-season tire designs.

Accidental Performance
As performance cars have become more highly refined, so has the demand for tires that can keep up. But while even mainstream automobiles can now travel fast enough and handle well enough to require high-speed-rated performance tires, such owners are not willing to park their quasi-performance cars during the winter. Nor are many of these "accidental performance tire customers" willing to switch to winter performance tires for those months when white stuff falls from the sky and makes the roads slippery.

The solution for the past decade has been the speed-rated all-season performance tire. This has been a uniquely American concept; in Europe, regulations require automobile owners to fit true winter tires if they live in areas where snow is likely.

The Compromises
But like anything else that purports to do everything for everyone, the all-season performance tire is at best a compromise. Generally the body and tread belts of a tire designed to withstand high-speed service are stiff and subsequently offer poor ride comfort. A tread pattern that promises winter traction is usually noisy, and it's often compromised by many small and individual treadblocks that can squirm and move when cornering hard on dry roads. The tread rubber itself must be composed of a compound that remains flexible at low temperatures for snow and ice traction, which usually makes it too flexible when driven hard in dry conditions. A large part of every major tire company's research and development over the past several years has been devoted to overcoming these all-season performance-tire compromises.

C3M Secret Weapon
Like everyone else, Michelin has also been looking for a way to eliminate many of these compromises. But the company had a secret weapon. More than ten years ago the tire giant began work on a new tire manufacturing process.

Traditional tire building comprises the assembly of layers of belts and extruded strips of rubber. Because each of these products must be carefully prepared ahead of time and brought to one assembly point, the process is both involved and inflexible. It also constrains the tire design engineer to create tires that are similar in design to what has come before.

The Michelin process, called C3M, was originally designed primarily to add flexibility to the tire-building process. Instead of assembling a group of prefabricated components into a tire, the C3M process actually builds up each individual tire from what are essentially its constituent individual materials-textile cord, steel cables and rubber. Each individual product can be placed anywhere on the tire, and the result has been a boon to the tire designer, now free to try new ideas.

Dan Osborne is a tire design engineer at Michelin tire and has been involved in the C3M process almost since its beginning, spending several years in France working on its development. He was well placed when Michelin decided to seriously attack the problems associated with all-season ultra-high-performance tires, and the result is the newly introduced Michelin Pilot Sport A/S. It's a tire that can only be built using the proprietary and highly secretive C3M process.

Three Treads Are Better Than One
Looking at the outside of the Pilot Sport A/S, it's hard to see what all the fuss is about. The tread pattern is relatively tame compared to offerings from some of the other tire manufacturers. Tire aficionados will approve of the solid center rib that reduces noise and improves wear and on-center steering feel. They also will notice the two wide longitudinal grooves at either side of the center rib, vital to good water evacuation on a wide tire design. The rest of the tread pattern is relatively straightforward, with sweeping lateral grooves and relatively robust shoulders. What isn't evident when merely looking at the part of the tire that touches the ground is the materials that are involved.