Australia MotoGP: Bridgestone Tire Debrief
Phillip Island MotoGP
Phillip Island usually provides mixed weather during the MotoGP weekend, and this season was no different with rain on Friday that delayed the motorcycles running by two hours and eventually resulted in a wet but drying session, showers that interrupted practice and qualifying on Saturday but then fine weather and the highest temperature of the weekend for Sunday’s race.
As expected, the temperature was cold but the new asymmetric rear motorcycle tire developed by Bridgestone for the Phillip Island MotoGP, with an extra soft compound right shoulder, performed well.
Dcuati MotoGP rider Casey Stoner was the runaway winner ahead of the Yamaha riders Jorge Lorenzo and Valentino Rossi, having emerged ahead of his race-long battle with Nicky Hayden.
Q&A with Tohru Ubukata – Manager, Bridgestone Motorcycle Tire Development Department
Q. How did the cold conditions affect tire performance over the weekend?
TU: “Especially on Friday and Saturday morning the track temperature was low, but no lower than we expected so this did not come as a surprise because we believe our spec choice has a wide enough operating range to cover such cold temperatures. The combination of rain, the cold and the high winds made the conditions very challenging for the MotoGP riders, but we can see from the laptimes that motorcycle tire performance was good in all conditions.”
“The left side of the rears were a harder compound to cope with the demands of the fast lefts but the right side of the rear slicks was softer to aid warm-up performance and grip in the cold. Even though tire temperature was lower than last year, it was still within their wide operating range. It was very tricky in the wet because the ambient temperature was even lower when it rained, but this is why we chose the soft compound wets. Overall, and taking into account rider feedback most of which was positive, I am happy with the performance of our tires this weekend.”
Q. What was the biggest challenge for the tires over the weekend?
TU: “Phillip Island is an unusual MotoGP circuit because the difference between the ambient temperature and the tire temperature, especially in the left shoulder of the rear tires, is greater than at any other circuit.”
“The ambient and track temperatures were generally low, but the temperature the left shoulders reach are the highest of the MotoGP season so balancing this was tricky. We use asymmetric rear slicks to manage this balance between warm-up performance in the right with durability in the left of the tires, but generally wet tires do not need to be asymmetric because the peak tire temperature is much lower so the difference between the temperature in each shoulder is much smaller than in the slicks.”
“Because of the nature of this MotoGP circuit and the fast left-handers though the left side of the wets reached a high temperature and this increased their wear rate and led to some riders feeling that the rear was moving a lot when the track started drying. Slick tire performance was good as proved by the laptimes, especially Casey’s, but I can say that the biggest challenge of the weekend was for the wet tires in the drying conditions.”
Q. How successful were the new rear slicks that used the extra soft compound in the right side?
TU: “I am very happy with the performance of our new asymmetric slicks. We developed them for Phillip Island MotoGP specifically for the cold conditions that we expected, and in these conditions they provided improved warm-up performance and good grip. I am pleased that we also received great feedback from the riders who all believe they are an improvement on the rear tires we brought here last year. We will adopt this extra soft compound into the asymmetric rear slicks we will use in Estoril and Valencia MotoGP because of the cold conditions we expect at each circuit.”