After the recent overseas trio of motorcycle races, the Portuguese Grand Prix represents the first half of the final back-to-back pairing of the 2010 MotoGP season. The Riders’ and Teams’ championships have been clinched, by Jorge Lorenzo and the Fiat Yamaha Team, but the Constructors’ title is still up for grabs, as is second position in the MotoGP riders’ championship.The Estoril circuit is one of the most technically challenging races on the MotoGP calendar for Bridgestone’s tires. Estroil has a very varied layout and nature with a multitude of different corner characteristics, corner loads and surfaces and so a well-balanced setup is important to allow the tires to perform consistently throughout a MotoGP lap.Top speed is high along the main straight with the MotoGP bikes reaching over 325km/h before braking heavily into turn one at Estoril, demanding a strong front tire.Ambient conditions are usually cold though, especially as the MotoGP race is held almost a month later than last year, and the tarmac is slippery so softer front tire compounds are required to generate grip.For the same reasons, softer rear tires are also required whilst balancing the demands of the fast Parabalica corner particular. The MotoGP circuit’s imbalance of four left-handed corners and nine rights mean that Bridgestone has selected asymmetric rear slick tires for Estoril.The right-handers are generally fast so the tire temperature in the right shoulder is high but the left-handers are generally slow, including the chicane which is the slowest corner on the MotoGP calendar, so tire temperature in the left side is much cooler.Particularly with the reinstatement of Friday morning practice, when the conditions are colder, tire warm-up performance is very important.After its debut success in Australia, Bridgestone are again incorporating the extra soft compound rubber into the asymmetric rear slicks to improve warm-up performance and grip on the slippery tarmac for the Estoril MotoGP.Hiroshi Yamada
(Manager, Bridgestone Motorsport Department) says: “After a long run of overseas races we return to Europe for the final back-to-back of the season and although the Championship has already been won, there is still a lot to play for further down the order with close battles being fought for second position and throughout the top ten.”“Estoril is being run almost a month later this season than in 2009 meaning we can expect colder conditions, but we have prepared for this by using our extra soft compound in our asymmetric rear slicks. I am pleased that this compound was so well received by the riders in Australia because we have been listening to the riders throughout the season and this extra soft compound has been developed in response to the feedback they have given us.”Tohru Ubukata
(Manager, Bridgestone Motorcycle Tire Development Department) says: “Estoril is a challenging mixture of slow-speed lefts, high-speed rights and interlinking straights that test all aspects of the rider, machine and tire package. The nature of the track changes from one corner to the next, and the tires also have to contend with a surface change during the lap after partial resurfacing work conducted in 2006.”“The use of asymmetric rear tires is also very important here to balance the tire temperature around the asymmetric layout. It’s a slippery circuit and the temperature is low so this demands softer compounds to generate grip, but the heavy braking points require a strong front tire and the fast and long right-hand corners necessitate harder compounds in the right shoulder of the rear slicks so we have to achieve a balance with our tire selection.”“Warm-up performance around the left-handers is particularly important, and because of this we will use the extra soft compound that we debuted in Australia in the left shoulders of our asymmetric rear slicks. I am pleased with the positive feedback from the riders after using our extra soft compound as we have developed it after listening to them throughout the season and working closely with them to always try and improve our tire offerings. This tire development is a very important aspect of our participation in MotoGP and ultimately filters down to improve our road tires.”Bridgestone slick compounds available at Estoril:
Front: Soft, Medium.
Rear: Medium, Hard (both asymmetric)