British MotoGP debrief with Masao Azuma

Yamaha Factory Racing’s Jorge Lorenzo rode one of the races of his career at Silverstone last Sunday to claim a special victory over Repsol Honda’s Marc Marquez and claw back valuable points in his MotoGP title defence.
 
The decision to shift the British Grand Prix from June to August was a masterstroke with the event enjoying fine weather throughout the three days of on-track action. A peak track temperature of 32°C was recorded during the race and tyre choice for the race was varied with all slick options being used and a significant part of the grid lining up on harder rear slick options.
 
Q&A with Masao Azuma – Chief Engineer, Bridgestone Motorsport Tyre Development Department
 
The qualifying and race lap records at Silverstone were smashed last weekend. Can you explain this big improvement in the general pace of the MotoGP bikes at this circuit?
                                                                                                                                 
“A lot of the improvement had to do with the dry, consistent weather we had over the weekend. This enabled the teams to find a setup that got the most out of the tyres and put it good use when it was needed most. We knew the one-thousand cc MotoGP bikes had the potential to go extremely quick around Silverstone and with our tyre allocation for this race featuring rubber compounds towards the softer end of the scale, the potential for a big reduction lap times was good. However, to see the existing Circuit Best Lap record beaten by almost two seconds in qualifying and the Circuit Record Lap lowered by almost a second in the race was outstanding. It is good to see such pace over a lap but for Bridgestone, we were most pleased with the overall race time which was about twenty-four seconds quicker than last year, representing an improvement of over one second per lap compared to the previous best time. This shows that the high pace was maintained through the race with a minimal degradation of performance over the twenty laps.”
 
There was a lot of variation in tyre choice for the race, both for the front and the rear. Can you explain what it is about Silverstone and the tyre allocation for this race that caused this?
 
“The rear tyre allocation for Silverstone is like the circuit, quite unique in that for the works riders we use the same, medium rubber compound on the ‘harder’ shoulder, which is the shoulder that is placed under the most stress while cornering which for this circuit is the right shoulder. We do this because our data indicates that the stress placed on the right shoulder is not so severe, so we don’t need to go harder than the medium compound on that shoulder. However, our asymmetric slicks need to ensure good temperature retention and warm-up performance on the lesser used ‘softer’ shoulder, which at Silverstone is the left side, so we use softer rubber compounds on that shoulder. So even the hardest option rear slick at Silverstone featured the medium rubber compound and as this compound has proved very popular this season. Another important factor was that all the afternoon sessions featured the same weather conditions and we had no rain. We have had a few instances this season where the harder rear slicks have been used in the afternoon practice sessions, only for conditions for the race being cooler, which has dissuaded the riders from selecting the harder rear slicks.”
 
The number of incidents seemed to increase in the morning sessions. Was this just because of the cool weather or were there other factors at play?
 
“Cooler temperatures always create more challenging conditions, there is no doubt about that but Bridgestone has made a big effort in recent seasons to improve both the warm-up performance and feel of our tyres to reduce risk in cooler temperatures. On Friday, MotoGP was the only class not to have any crashes in the morning session and on Sunday morning, three of the five crashes happened at Vale which features a small dip which can unsettle the front of the bike in what is quite an extreme braking zone. This point of the track has always been challenging for the riders, and the cold weather exacerbated the situation. As always we will examine rider feedback, tyre and telemetry data to see if changes need to be made for the future, but with the harsh braking zones at Silverstone if you go too soft with the compound selection, braking stability can become an issue. Front tyre selection at Silverstone is always a juggling act, and I believe we got the balance right but there is no denying that in cool conditions, parts of the Silverstone circuit will always be difficult for riders to manage.”