San Marino GP: Bridgestone debrief

San Marino Grand Prix debrief with Tohru Ubukata Bridgestone slick compounds available: Front: Medium, Hard. Rear: Medium, Hard Bridgestone have been successful at the San Marino Grand Prix since it returned to the MotoGP calendar in 2007 ...

San Marino Grand Prix debrief with Tohru Ubukata

Bridgestone slick compounds available:
Front: Medium, Hard.
Rear: Medium, Hard

Bridgestone have been successful at the San Marino Grand Prix since it returned to the MotoGP calendar in 2007 and Bridgestone-shod riders have always qualified on pole and won there since then. This year, the achievement was a new lap record set by Valentino Rossi as he dominated the race to score his sixth grand prix win of the season. He was followed across the line by Fiat Yamaha teammate Jorge Lorenzo and Repsol Honda's Dani Pedrosa. Three riders were involved in a crash in turn two which allowed the Hondas of Dani Pedrosa and Toni Elias to fight for the early lead, but the Fiat Yamaha duo soon came to the fore and Rossi controlled the pace of the race from the front.

Q&A with Tohru Ubukata - Manager, Bridgestone Motorcycle Tyre Development Department

Another new lap record was set during the San Marino Grand Prix; what can you say about this?

"Of course I am very happy as it demonstrates the level of performance our tyres are delivering and the speed they are allowing the riders to ride at. We have no tyre competition in MotoGP anymore, but the fact that six new lap records have been set this season gives a good comparison of the level of performance of our tyres this year.

"This season, new lap records have beenset by Valentino at Jerez, Assen and Misano, by Jorge at Brno and Indianapolis, and by Dani Pedrosa at Sachsenring. Jerez, Assen, Brno and Misano all have high average lap speeds and both Sachsenring and Indianapolis have abrasive surfaces, so I am very pleased with the performance of our tyres in these demanding conditions."

Why did rear tyre compound choices vary during the race but the front tyre choices did not so much?

"During the race the ambient temperature was cooler than during both qualifying and Friday free practice, so this is the main reason that many riders chose the softer option rear tyre. However Misano has many bumps especially in braking zones, and these can make the rear wheel hop under heavy braking. This puts all the load of the bikes onto the front tyre so riders need very good front stability to be able to push. The hard compound front slick tyre is stiffer than the medium compound, so gives improved stability, and that is why most riders chose this option."

The Indianapolis Motor Speedway has 10 left- and six right-handed corners and asymmetric tyres were used there, but Misano has six left- and 10 right-handers and symmetric tyres were used. Why is this?

"Even thoughMisano has six left- and ten right-handed corners, the opposite of Indianapolis, asymmetric tyres were not needed here because of the temperature differential between the right and left shoulders of the tyres. We only use asymmetric tyres when one side of the tyre is put under significantly more stress and load than the other and thus operates at a higher temperature, and at Misano the temperature differential is much smaller than it was in Indianapolis. Also, the layout of Misano means that there is a regular flow of right- and then left-handers, so each side of the tyre maintains operating temperature through the lap rather than cooling gradually between corners.

Where will asymmetric tyres be used until the end of the season?

"Actually, of the four races left in the season we will bring asymmetric rear tyres to three of them. They will be used at the next round in Estoril, at Phillip Island and at the last round in Valencia."

-credit: bridgestone

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About this article
Series MotoGP
Drivers Valentino Rossi , Jorge Lorenzo , Toni Elias , Dani Pedrosa , Phillip Island