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GP Week : Issue 172
CHATTER RETURNS TO HAUNT MOTOGP RIDERS ROSSI: “DON’T EXPECT A DUCATI REVOLUTION WHEN I’M GONE” SPIES FITS BRAKE SCOOPS AFTER MOTEGI DISASTER All factory teams affected Sepang’s generally well-liked Tilke- designed circuit came in for stinging criticism over the GP weekend, as the well-used surface shared with Formula One brought out the worst in the Bridgestone tyres. As well as a lack of grip, the long corners were generating highly destructive and hard to fix tyre chatter – and it wasn’t just the two factory Honda riders affected. Other riders were experiencing the phenomenon of a violent vibration, thought to be harmonically generated, for the first time. Chatter was a problem earlier in the season, particularly for Repsol Honda pair Stoner and Pedrosa after the mid-season switch to softer-construction tyres; but chassis and other revisions seemed to have solved the worst of the problem. At Sepang, it was back in spades. For Pedrosa, “the bike is even chattering in a straight line;” while Stoner said: “If other riders are having it. we’re having it ten times worse.” But complaints came from all sides. For satellite Honda rider Stefan Bradl, “it is a new problem, that we have not experienced before with this bike. And we can’t fix it.” Yamaha and Ducati riders were also suffering badly, with Cal Crutchlow saying: “No grip, and massive chatter.” For Rossi, the reason was the surface, at a track heavily used for testing as well as national and international events. “It’s worn out. It needs to be resurfaced,” he said. Valentino Rossi predicts that next year’s Ducati Desmosedici will be much like the present one ... made by the same people in the same way, and requiring “a basic problem to be solved”. And he poured cold water on thoughts that Audi’s investment and vast engineering resources would make a difference in the near future. “At first it seemed that Audi would have changed many things in a short time, but now I believe there will be no revolutions for the coming year,” he told Italian media, according to an interview in GPOne.com. Rossi admitted: “I do not know the ideas of Filippo Preziosi and Ducati for the future;” then added: “but I think it is a basic problem to be solved.” His successors Dovizioso, Spies and Iannone, who will join Hayden in factory-backed “senior” and “junior” teams next year, will take little comfort from his words. Both are reserving judgement as they prepare to take on the task at which Rossi failed – of returning the Italian machines to the front positions it occupied in the hands of Casey Stoner. ‘It’s the way I brake’ Many riders had brake problems at the punishing Motegi circuit ... but none as bad as Ben Spies, who ran off and crashed on only the second lap after he’d already run out of stopping power. A week later, at Sepang, the luckless factory Yamaha rider’s M1 had cooling air scoops fitted, to avoid any repetition. Motegi has a several slow corners approached at high speed, and with the new weight and power of this year’s 1000cc machines it was testing the brakes to, and in this case beyond, their limits. Already after practice Spies had reported his front discs were close to 1000 degrees centigrade, triggering very high wear rates and compromising stopping power. Further analysis of data in the following week clarified the problem, and showed that in his first lap in Japan, his pads had already worn down by two millimetres. “I was probably worst from the way I brake,” he said. Spies’s initial application is very hard and fast, setting off the excessive heat build-up. The data also showed that when he ran off the brakes were only delivering 30 percent of full power, at a corner with a speed loss of 180 km/h (Brembo figures). Until Motegi, brake issues were rare, but Spies’s experience suggests that the rule limiting front brake disc to a maximum diameter of 320mm might need modification to match the meatier and mightier 1000cc generation. MOTOGP >>> NEWS silkolene.com Champions Choice The oil choice of three 2012 CHAMPIONS! Shane Byrne British Super Bikes Keith Farmer British Super-Stock Glen Richards British Super-Sport 14 GPWEEK.com // 14 GPWEEK.com // PARTNERS: