Bridgestone MotoGP: Phillip Island Test Debrief Q+A with Hiroshi Yamada – Bridgestone Motorsport – Manager Motorcycle Racing Bridgestone continued its extensive pre-season tyre testing with four of its five teams at the technically challenging Phillip Island circuit in Australia this week. Bridgestone Motorsport’s Motorcycle Racing Manager, Hiroshi Yamada believes the test was crucial in terms of season-long tyre development and for October’s Australian GP. How did this week’s programme differ from the Sepang test last week? “The programme for this week’s test was to continue development of our new rear tyres for the 800cc bikes, as well as to work specifically for the Australian GP later in the year. Phillip Island is a technical circuit and quite hard on tyres because we experience higher tyre temperatures than on any other track during the season. We do not get so many opportunities to test at Phillip Island so we must capitalise on our trip every time.” What tyres were tested this week? “We took a wide range of tyres this week, as we did in Sepang, in order to obtain as much data as possible from the eight Bridgestone-shod riders that took part in this test. We took a total of 1,100 tyres including new rear constructions and shapes, as well as qualifying rubber, all of which gave very useful results.” Qualifying was unusually problematic for Bridgestone at Phillip Island last year. Were any improvements found during this week’s session? “The major issue which we encountered in last year’s Australian GP qualifying was that our one-lap tyres did not retain sufficient grip levels for the entire lap. This forced our riders to conserve their tyre by backing off in less critical sections of the lap in order to keep the grip for the all-important final corner. One of our priorities for this week was to look deeper into this problem. As a general guideline, we expect around one second per lap improvement from race tyre to qualifying tyre, but we are still only seeing 0.5s gain around Phillip Island. We took several qualifying tyres this week and we got some extremely valuable feedback from our teams to resolve the problem for this year’s GP.” How was race tyre performance? “Most of our riders conducted long runs on our new rear tyres and we were able to see some impressive lap times during race simulation work. We are still looking into finding the limit which ensures our tyres are at optimum performance for just the right distance. The initial results show lap times on this construction and shape can be quick and consistent, which is encouraging, but our next planned step is to work on the best performance ratio.” Do any of the results from these opening two tests give you cause for concern? “I am not concerned at all, in fact I have been pleasantly surprised by the performance of our tyres in Sepang and Phillip Island. We have been able to use this week’s Australian test to verify initial results from Sepang as we begin to finalise the direction for tyre development for the coming season. We do not conduct tyre tests with our teams assuming that everything is going to yield positive results. Sometimes we can make even more progress by seeing something that does not work as well, so we are grateful for the support our teams give us during this crucial test phase. We have two more teams for this season so we are able to obtain more test data and we hope this will allow us to be more consistently competitive during the season than ever before.” Will the 2007 Bridgestone tyres be the same across all five teams? “We pride ourselves on providing tyres to each of our teams fairly at all times. A tyre that works well on one bike may not work as well on another so we tailor our service to each team and also to each rider. Data that has been acquired over these winter tests has allowed us to identify areas for individual improvement within each team, whether tuning the tyres to work better with the bike set-up or with the riding style.” Does Bridgestone plan to introduce 16-inch front tyres this season? “We do not intend to produce 16-inch front tyres for the coming season. We have previously evaluated the possibility of introducing a smaller front tyre, but concluded that the 16.5-inch offers the best performance for our teams, even with the introduction of the 800cc bikes for 2007.”