Bridgestone Press Release: Masao Azuma On Changing Grip Levels And Hard Front Tires At Indianapolis

Indianapolis MotoGP™ debrief with Masao Azuma

Tuesday, August 11 2015

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

Repsol Honda Team’s Marc Marquez won last Sunday’s Indianapolis Grand Prix ahead of the Movistar Yamaha MotoGP pair of Jorge Lorenzo and Valentino Rossi who finished in second and third places respectively.

After track temperatures reached almost sixty degrees Celsius on Friday afternoon, conditions for the race were much cooler with a peak track temperature of 38°C recorded. During the race, Marquez set a new Indianapolis Circuit Record Lap of 1’32.625 on the twenty-third lap and also set a new overall race time record of (41'55.371), beating the old record by twelve seconds.

Q&A with Masao Azuma – Chief Engineer, Bridgestone Motorcycle Tyre Development Department

The Indianapolis Motor Speedway is a very demanding circuit for tyres, particularly for the rear. Given the severity of the circuit and the big difference in weather conditions between the practice sessions and the race, what’s your assessment of tyre performance at this year’s Indy Grand Prix?

“Indianapolis is a very demanding circuit and as well as being severe on tyres, the grip level can vary quite a lot over the weekend. This year however, although the grip of the tarmac was low during the first sessions, overall the conditions were quite good for this circuit, even with track temperatures reaching well into the fifty degree Celsius range. If you look at the track temperatures on Friday afternoon compared to the race, the difference is almost twenty degrees Celsius yet tyre performance remained very good in these highly variable conditions, so I am quite pleased with this. During the race we had some light drizzle but even so, there was a new Circuit Best Lap and overall race time record set and the riders were able to push at 100% throughout the race. This is a good outcome for us and shows that our tyre allocation for this year’s Indianapolis Grand Prix was well suited to this circuit.”

Bridgestone has been quite active in tyre development this year, so where there any significant changes in the tyre allocation for this year’s Indianapolis Grand Prix?

“We didn’t have to change too much this year as last year’s Indianapolis tyre allocation performed quite well. However, given the increased performance of the open class machines this year, we revised our allocation so that the soft option rear slick was closer to the medium rear in its composition. This change worked well as many open class riders were able to use the soft compound rear slick for the race with good results. For the front tyre, the availability of the new hard compound front slick at Indianapolis was a good addition to our tyre allocation and was well received by the riders. So there were minor changes made compared to last year’s Indianapolis Grand Prix, but the changes made had positive results.”

Last year at Indy just two riders selected the hard compound front slick for the race, with most preferring the medium front. This year however, twenty-one riders selected the hard compound front. Why was there such a huge shift in front tyre preference from the medium to the hard compound front slick in 2015?

“The hard compound front slick that we brought to Indianapolis this year was the first time this specification of tyre has been available at this circuit. Last year the riders selected the medium compound front slick as although it lacked the braking stability of our previous hard compound front slick, its cornering performance and feedback was quite a bit better than the hard front. However, our new hard compound front slick offers the same excellent braking stability as before, but with better edge grip and feel than and this combination made it extremely popular this year. Therefore, the shift in preference from the medium to the hard front slick at Indianapolis this year was due to the improved grip and feel of our latest specification hard compound front slick.”

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