Bridgestone Press Release: Shinji Aoki On Wet And Dry Tires In Austin

Bridgestone issued their customary post-race press release discussing how their tires fared at last weekend's race in Austin, Texas:

Americas MotoGP™ debrief with Shinji Aoki
Wednesday 15 April 2015

Bridgestone slick compounds: Front: Soft, Medium & Hard; Rear: Soft & Hard (Symmetric) & Medium (Asymmetric)
Bridgestone wet tyre compounds: Soft (Main) & Hard (Alternative)

Marc Marquez won his third consecutive race at Circuit of the Americas last weekend, the Repsol Honda star taking the chequered 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 Tyre 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 tyres 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 tyres performed at this demanding circuit. Our main wet tyre 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 tyres, with low levels of tyre wear. The alternative, hard compound wet tyre 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 tyre choice and tyre performance for the race?

“Although temperatures were considerably warmer for the race, it didn’t seem to have a big influence on tyre 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 tyre 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 tyre 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 tyre 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 tyre, 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 tyres 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. ”

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Vale said his front tire was "destroyed." I know these are a PR effort, but it's a pretty glaring thing to leave unaddressed.