Americas MotoGP debrief with Shinji Aoki

April 15, 2015

Marc Marquez won his third consecutive race at Circuit of the Americas last weekend, the Repsol Honda star taking the checkered flag ahead of Ducati Team’s Andrea Dovizioso and Movistar Yamaha MotoGP’s Valentino Rossi.
The race weekend was subjected to variable weather with cool, rainy periods giving way to warm and sunny weather on Sunday. The peak track temperature of 40°C during was the warmest reading for the whole weekend.
Q&A with Shinji Aoki – Manager, Bridgestone Motorsport tire Development Department
On Friday the MotoGP riders had their first ever wet session at Circuit of the Americas. What can you tell us about the grip level of the circuit in the wet, and how your wet tires performed?
 “The grip level of the wet COTA tarmac was quite good compared to other circuits, and the riders were happy with how our wet tires performed at this demanding circuit. Our main wet tire option was our soft compound which offers a lot of grip, but the durability of this option in Austin was also very good as some riders completed half a race distance on set of wet tires, with low levels of tire wear. The alternative, hard compound wet tire was also available but given the good performance and durability of the soft compound wet at COTA, I don’t think many riders would have chosen to use it if we had more wet sessions later in the weekend.”
It seemed a lot warmer on Sunday compared to earlier on the weekend. Did this have an effect on tire choice and tire performance for the race?
 “Although temperatures were considerably warmer for the race, it didn’t seem to have a big influence on tire choice for the race. There was maybe only a couple of riders who switched from the medium compound to the hard compound front slick for the race, but the operating temperature for our medium compound front slick is so good that most riders felt comfortable using this option for the race. In regards to tire performance, the warmer temperatures didn’t have a considerable effect. Some riders did mention that the grip level during the race wasn’t as good as the day before, but this was likely related to the rain the night before rather than the temperature change.
Unfortunately, due to the rain on Friday and cool temperatures on Saturday no riders chose to evaluate the hard compound rear slick during practice, and seeing as this tire option was used by the race winner at this track in the last two years, I was curious to see how this option would perform this weekend. I believe had some riders assessed it earlier in the race weekend, it would have been a good race option, however, our medium compound rear slick handled the conditions well so it was still a positive outcome for us.”
A few riders mentioned that the right side of the front tire is put under considerable stress at Circuit of the Americas. Would asymmetric front slicks be well suited to this track?
 “There are sections of this circuit that place a lot of stress on the right shoulder of the tire, but there are more left hand turns, so overall this circuit is still quite balanced. As we can only bring three different options of front slick to each race, I think the soft, medium and hard symmetric front slicks were the best options for this circuit. The soft front worked well when the circuit was cool with some damp patches, while the medium & hard were well suited when the track was fully dry and warmer. I think an asymmetric front slick may have performed well in certain conditions at the circuit, but as the riders were happy with the grip and stability on the left side of the medium and hard compound front slick, going softer on the left side of those tires might not have brought much of an advantage. I can say that having three front slick options on offer at Circuit of the Americas this year was a welcome change for the riders and gave them enough options to deal with the variable conditions. ”