Valencia is a port city on Spain’s Mediterranean coast. It is also a center for orange-growing, so the trees can be seen from many local highways. Folded into limited acreage, the 14-turn, predominantly left-hand Circuit Ricardo Tormo is the epitome of the modern “bullring”: 30 laps of the 2.49-mile circuit are required to complete the race distance of 74.7 miles. Fast and flowing it isn’t!
In 2011, Bridgestone, maker of the spec tires used in MotoGP, described the track as “a tight and twisty affair that does not give the tires much rest during a lap, so it is very important that teams get their bikes set up to use them most efficiently. With little chance during a lap for the tires to cool down, excess sliding can easily generate excess tire temperature and accelerate tire wear.”
This is just what I saw at Valencia in 2004, when then-novice MotoGP rider Nicky Hayden on a Honda RC211V strove to make his dirt-track-derived riding style of that time do double-duty in roadracing. As his tire overheated from all the sliding, Hayden lost position, obliging him to ride harder, causing the tire to fade all the faster. He finally tipped over that day.
Many fans are disappointed by this view of racing—that the race is not necessarily to the swift but is rather to those who are both swift and mindful. The task is to go as fast as possible, given the limitations imposed by tires. Yes, a rider must establish a “rhythm,” but he cannot give himself to some ecstatic “flow state.” He must remain fully aware, constantly judging the condition of his tires and those of his competitors. Tire condition can be looked at as a sort of “fuel” whose remaining quantity must be used with fine judgment.
Last year, Bridgestone’s Hirohide Hamashima, who also has extensive Formula One tire experience, said, “If a bike’s setup isn’t optimized, it is easy to generate excess tire temperature, especially as softer compounds are generally required in cool ambient conditions.”
This is analogous to the situation with rain tires. Because water cools the tires, it is tempting to choose a softer compound with more grip. But if the cooling effect is lost (rain stops, sun appears), the higher grip of softer rubber transforms to grease, and the rider is finished. So it is with softer rubber in cooler weather, which is certainly possible in November!
Hamashima also said that “the front tire must be strong to cope with the heavy braking loads into the first corner.” These tires run with low inflation pressure to give large footprints, but that low pressure reduces the amount of the tire’s stiffness that comes from inflation pressure tensioning the tire’s fabric. (Thin stainless propellant tanks of Atlas ICBMs had to be pressurized when empty to prevent buckling.) Therefore, some of the stiffness shortfall must be made up by the carcass itself.
This was also a problem when Michelin first adopted such low pressures in 2006. Valentino Rossi preferred a heavier, stiffer carcass for corner stability. When I asked him what happened without such a stiff carcass, he said, “The machine jumps.” This suggests that under extreme load, a buckling wave passed through the footprint.
Earlier this year, Casey Stoner complained of the lack of such carcass stiffness in the new “33” fronts that had replaced the fronts on which the RC213V motorcycle was developed. He said that it created braking instability. But in our new world of racing managed for business goals, the teams must adapt motorcycles to tires and not the other way around, as in the days of tire competition.
Last year at Valencia, Bridgestone supplied soft/medium fronts and medium/hard rears. The softer of the two rears carried extra-soft rubber on the less-used and thus cooler-running right side of the tire.
With Jorge Lorenzo already MotoGP champion, Valencia will decide little but the order of lower championship positions. Stoner may wish, in this his last MotoGP ride before retirement, to reassert his abilities. We respect him and his abilities! Technicians, meanwhile, will be worrying over the classic dirty-laundry problem: Which of these well-used engines (riders now get only six “builds” per season) can reliably go the distance without blowing an embarrassing shower of parts and oil onto the track?
|Air/track temps F||66/77||79/93||66/84||72/81||63/61|