French MotoGP debrief with Bridgestone's Masao Azuma

May 19, 2015

The French Grand Prix saw the Movistar Yamaha MotoGP team dominate proceedings Jorge Lorenzo and Valentino Rossi scoring a one-two result, while Ducati Team’s Andrea Dovizioso continued his rich vein of form by finishing in third place.
Practice and qualifying for the French Grand Prix took place in extremely cool weather, with some rainy periods. Track temperatures were as low as 13°C during Free Practice 3, but a warm change on Sunday saw a large increase in track temperatures, with a peak recording of 42°C during the race. The warmer conditions helped the riders set a sizzling pace during the race, with Rossi setting a new Circuit Record Lap of 1'32.879 and Lorenzo’s race time also setting a new record, beating the old mark by nineteen seconds.
Q&A with Masao Azuma – Chief Engineer, Bridgestone Motorsport Tire Development Department
At Le Mans we had another Grand Prix where the temperature on race day was quite different to the preceding days. What affect did this have on tire performance and the condition of the tarmac?
“It was considerably warmer on Sunday and although the change in temperature didn’t have a noticeable effect on overall tire performance, it seems the 21°C rise in track temperature compared to qualifying may have compromised some riders’ bike settings. Le Mans is a low grip circuit and is especially sensitive when it comes to finding a bike setting that gets the best performance out of the tires. For the race the majority of riders used the same combination of soft compound slicks front and rear that they used in qualifying, but some riders commented that the feeling from their bike was quite different in the race. This suggests some bikes coped better with the change in temperature than others. Some riders complained of a vague feeling from the front of the bike, particularly early on in the race, and this can happen when riders are pushing with a full fuel-load on circuits with low grip levels. The fact that the top three riders completed the race quicker than the existing Le Mans overall race time record shows that it was possible to extract high performance from the tires in such conditions.”
Despite the much warmer temperatures, no one selected the medium front slick at Le Mans. In the past, hot temperatures often result in riders using harder front tire options; why wasn’t this the case last weekend?
“Due to the extremely cool conditions on Friday and Saturday, the riders were unable to evaluate the medium compound front slick, so they were hesitant about selecting it. I am sure that if some riders had the chance to assess the medium front slick in warmer conditions, then we would have seen some riders select it for the race. However, it is risky to select a race tire without testing it previously over the weekend. In most cases, the bike needs to be setup accordingly to make the best use of a particular tire and in the case of the medium front slick, the riders and teams had no reference data from previous sessions to work with. An additional factor in why the medium front slick wasn’t selected for the race was that the riders felt the soft front offered good performance over race distance.”
In the five races so far we’ve already three new race lap records and two qualifying lap records. tire performance in 2015 seems quite extraordinary. Was this a development focus for Bridgestone this year?
“A rider’s ability to set lap records is a combination of many factors, such as the weather and track conditions, bike performance and of course, tire performance. Since becoming Official tire Supplier to MotoGP, our primary goal has been improving rider safety by offering tires with better warm-up performance, feel and control. Now the riders are happy that as soon as they set off they have excellent feel from their tires, so they are not only safer but in many cases, faster. Although outright performance is a secondary consideration in our technical development, we are pleased that the riders continue to break many lap records every year. Racers always want to push themselves to the limit, and now we are allowing them to do that with more safety than ever before.”