As always, Bridgestone issued a post-race press release debrief with a senior representative. Today it was the turn of Shinji Aoki, head of the Japanese tire manufacturer's motorcycle tire development department. Aoki discusses the challenges faced by racing on a drying track, the purpose (or otherwise) of scrubbing in new wet tires, and the fact that the harder of the two compounds Bridgestone brought to the circuit went unused.
Dutch MotoGP™ debrief with Shinji Aoki
Wednesday, 2 July 2014
Bridgestone slick compounds available: Front: Extra-soft, Soft & Medium; Rear: Soft, Medium & Hard (Asymmetric)
Bridgestone wet tyre compounds available: Soft (Main), Main (Alternative)
Last weekend’s Dutch TT at Assen was affected by variable weather conditions that resulted in the race being a flag-to-flag affair at which Repsol Honda’s Marc Marquez won ahead of Ducati’s Andrea Dovizioso and Dani Pedrosa on the other Repsol Honda RC213V.
Fine conditions on the opening day of practice gave way to increasingly poor weather that culminated in a downpour of rain during the lead up to Saturday’s race. All except two of the twenty-three starters at the Dutch TT, Broc Parkes and Yonny Hernandez who started on slicks, started on soft compound wet tyres, but by the time a third of the twenty-six lap race had been run, all entrants had changed to their second bikes fitted with slick tyres.
Q&A with Shinji Aoki – Manager, Bridgestone Motorcycle Tyre Development Department
Conditions for the start of the race last Saturday at Assen were wet but the track dried very quickly. Are you satisfied with how both the slick and wet tyres performed?
“The kind of mixed conditions that we experienced for the race are really challenging for the riders. Grip levels can change from corner to corner, so the riders need tyres that get up to temperature quickly and have very high grip levels. The fact that we had almost no incidents during the race and the riders managed to show quick pace on a drying track that still had some patches of water was very positive for us. The wide working temperature range of our slick and wet tyres was one of the key factors that allowed the riders to push in the tricky conditions with confidence.”
During Free Practice 3 when the track was only slightly wet, some riders left their box on wet tyres only to return to the pits after not even completing a single lap. Can you explain what is happening here?
“Some riders like to ‘scrub’ a set of wet tyres by doing a lap on them in case they need to be used later in a race situation. The purpose of scrubbing is not to remove some kind of coating on the tyre as some people believe; rather it is purely a mental exercise for some riders as perhaps they feel more confident pushing on a set of wet tyres that aren’t brand new. Even when there is no possibility of rain on race day, some riders will still scrub a set of wet tyres during the morning Warm Up session in case there is unexpected rain before the race. Technically speaking, a scrubbed wet tyre has no advantage in terms of grip compared to a new tyre as our wet tyres offer maximum grip at the very beginning of their life.”
No Factory Honda or Yamaha riders tried the hard rear slick over the race weekend at Assen. Was this due to the weather conditions or some other factor?
“The weather conditions on the Thursday at Assen were well suited for the hard specification rear slick, but as it was the first day of practice, the Factory Honda and Yamaha riders preferred to use the medium rear slick to assess grip levels and find a base bike setup. This is quite a normal procedure. Some of the riders planned to evaluate the hard rear slick during practice on Friday, but the weather was much cooler and we had intermittent rain and in these conditions, the medium compound rear slick was the better choice. In any case, the difference between the medium and hard specification rear slicks provided for Assen are quite close, so if track temperatures for the race were towards the forty degree range, some riders would have selected this option.”