Dutch Grand Prix, Assen: Bridgestone debrief with Shinichi Yamashita
Last Saturday’s Dutch TT at the fabled Assen circuit saw Repsol Honda’s Casey Stoner bounce back to score his third win of the season ahead of teammate Dani Pedrosa and Monster Yamaha Tech 3’s Andrea Dovizioso. The reigning champion now sits level with Yamaha Factory Racing’s Jorge Lorenzo in the MotoGP™ standings.
Conditions for the race were warm with track temperatures reaching 40°C in complete contrast to the cold conditions experienced last year. Overall, tyre performance for the majority of the field during the Grand Prix weekend was good, but unfortunately a few riders experienced tyre problems in the latter stages of the race prompting a full and thorough investigation by Bridgestone into the issue.
Bridgestone slick compounds available: Front: Soft, Medium. Rear: Medium-soft, Medium (Asymmetric)
Bridgestone wet tyre compounds available: Soft (Main), Hard (Alternative)
Q&A with Shinichi Yamashita – General Manager, Bridgestone Motorsport Tyre Development Department
The Dutch TT was held in generally warm and dry weather. How did the conditions affect tyre choice?
“Generally, conditions were good though there was intermittent rainfall that affected both the FP3 and qualifying sessions. Compared to last year, the track temperatures were substantially warmer and the pace was much faster so with no relevant data to reference, tyre selection, particularly for the rear, was somewhat challenging for the riders and teams. Also, the rain that did fall on Friday made it difficult for some teams to perform longer runs on both rear slick options to see what would work best for them during the race.
“For the front tyre, all riders preferred the extra cornering stability of the harder option, though rear tyre selection was more varied, with most riders preferring the greater right-shoulder edge grip of the softer rear option over the greater durability of the harder rear slick.”
Can you explain the tyre choices for the race? All the CRT riders as well as the Honda’s chose the softer rear, while all Yamaha and Ducati riders chose the harder rear slick.
“It should be noted that both asymmetric rear slick options at Assen used the same medium compound rubber on the right shoulder and so it was the trade-off between grip and durability on the left side of the tyre that was the definitive factor for rear tyre choice at the Dutch TT.
“Yamaha and Ducati didn’t select their tyres until right before the beginning of the race and perhaps wanting to ensure greater durability in the warm conditions, opted for the harder rear slick. On the other hand, when Honda tested the softer rear slick during practice and qualifying they found they could make it work well in the warm temperatures and as a result they showed strong, consistent pace throughout the race. Due to their slightly lesser pace the CRT bikes don’t generate as much force on the tyres as the works bikes and so the riders on these machines preferred the greater warm-up performance of the softer rear slick.”
What can you say about the problems some riders experienced with their rear tyre at Assen?
“Yes, regrettably some riders experienced problems with their rear tyre during the Dutch TT, a situation we humbly apologise for. As soon as it was apparent that there was a problem, our race engineers and technical staff at Assen convened to perform an initial examination of the affected tyres and to gather feedback from the riders on what happened during the race.
“This is something that Bridgestone is taking very seriously and after the race I ensured the affected tyres got back to our Technical Centre in Kodaira, Japan as soon as possible where they are now undergoing comprehensive analysis in our laboratory. We are making every effort to determine what occurred.”
Source: Bridgestone Motorsport Press Release