Australian Grand Prix debrief with Tohru Ubukata Bridgestone compounds available: Front: Wets - Soft Slicks - Soft, Medium Rear: Wets - Soft Slicks - Hard, Extra hard (asymmetric) The Australian Grand Prix was challenging and changeable in...
Australian Grand Prix debrief with Tohru Ubukata
Bridgestone compounds available:
Wets - Soft
Slicks - Soft, Medium
Wets - Soft
Slicks - Hard, Extra hard (asymmetric)
The Australian Grand Prix was challenging and changeable in equal measures. Early rains left the track dirty on Friday, and then Saturday's free practice was interrupted by another downpour, but it held off for the qualifying session and the race. Casey Stoner won from Valentino Rossi and Dani Pedrosa, all of whom favoured the softer Bridgestone slick options for the extra grip they provided in the cool conditions. Only the Suzuki Team's Loris Capirossi and Chris Vermeulen used the harder option rear tyre, with the rest of the field on the softer options. With just two races left this season, Valentino Rossi's championship lead is now 38 over teammate Jorge Lorenzo with 50 points still available, and a resurgent Casey Stoner has reclaimed third from Dani Pedrosa.
Q&A with Tohru Ubukata - Manager, Bridgestone Motorcycle Tyre Development Department
How can you summarise the weekend from the point of view of tyre performance?
"We know that Phillip Island is a difficult track for tyres but I am happy with the new specifications of rear tyre that we developed specifically for this weekend. The conditions throughout were quite cool so the softer option was clearly the faster choice because of the improved level of outright grip it provided, but even the extra hard rear gave good consistency. We had no problems with durability all weekend and this was the intention of the new specification rear tyres so I can say they worked well. More durability always comes as a trade-off with peak grip, but the laptimes were within 0.03seconds of the lap record indicating that overall performance was still good, so I believe we achieved the right balance."
The track temperature was quite cool during the weekend, certainly cooler than we are likely to see in Sepang next weekend. What is it about Phillip Island that stresses the rear tyres?
"We saw a lot of TV coverage and slow motion clips of bikes sliding through the turns, especially the left-handers at the end of the lap. This looks spectacular and is a very impressive display of bike control by the riders, but it is tough for the tyres! It is this spinning and sliding of the rear tyre that generates significant temperature in the rubber, especially in the left shoulders given the number of fast left-handers at Phillip Island, and this is the reason that we developed the more durable asymmetric rear tyres for this grand prix. As a tyre spins, the friction between the rubber and the track generates heat. The more it spins, the higher the temperature. Above its optimum operating temperature, the hotter a tyre gets the less grip it has and so the more it will spin, and so on. This is why it was important to strike the right balance of heat durability to prevent this happening whilst maintaining a good level of overall grip, and I think that the lap times and the overall race time show that we achieved this."
What can you say about wet tyre performance after the rainfall on Saturday?
"At Phillip Island heavy rain can come suddenly, so the track can very quickly go from dry to very wet. Also, the track does not dry too quickly, so there were no intermediate conditions on Saturday, just full wet. At this time of year here the temperature is cool, and the rain cools the track surface even more, so we decided to bring the soft compound wet tyres, as we last used at Donington Park for the British Grand Prix. Of course in the wet, the tyres generate less temperature so we can use softer compounds to maximise peak grip. With a lot of water on the track and in the cold ambient conditions, the soft wet tyres provided good grip and consistency which allowed the riders to set some good laptimes so I am pleased."