Bridgestone’s Masao Azuma debriefs after red-flagged Sepang MotoGP

This year’s Malaysian Grand Prix was red-flagged after thirteen laps in an intense tropical downpour, with Repsol Honda’s Dani Pedrosa claiming victory ahead of Yamaha Factory Racing’s Jorge Lorenzo in second place and teammate Casey Stoner, who finished third. With varied track conditions over the weekend, riders experienced every specification of tyre brought to Sepang by Bridgestone. All riders opted for the hard compound front wet tyre during the race, while rear tyre choice was equally divided across the grid with ten riders each selecting the soft and hard compound wet tyre. Masao Azuma, chief engineer in Bridgestone’s Motorsport Tyre Development Department speculated on why riders may have experienced less grip at Sepang, even before the rain came.

“[The] reason for this is unclear but the grip levels of the circuit this weekend weren’t as high as experienced earlier in the year. During winter testing grip levels were better and this was reflected in quicker lap times and a general improvement in the level of performance. In February, lap times in the 1:59 bracket were recorded, and the best lap time last weekend was a 2:00:30. Also, more riders experienced chatter this weekend than during winter testing, even at the second test when we introduced the new specification front tyre, so the condition of the circuit was obviously very different compared to February.
 
“Though we don’t know the exact reason why this situation occurs, this tendency for the Sepang circuit to have less grip during the October race weekend compared to winter testing happens almost every year. The track temperatures in winter testing tend to be higher and there is less rainfall at this time, so this could be a contributing factor to the better track condition at this time.”

As for which compound rear wet tyre was the superior choice, Azuma admitted it was hard to say: “Just like in slick tyres, softer rubber compounds in wet tyres give better warm-up performance and grip compared to hard compounds which grant better durability and cornering stability. With the weather being so variable in Malaysia, it was difficult to tell which wet rear tyre would work best for the race, though due to the warm temperatures at Sepang which dry out the track quickly and make warm-up performance not as critical, our main wet tyre for this race was the hard compound option.
 
“The heavier rain just before the red flag increased the amount of standing water on track to the point where regardless of which compound a rider selected, grip levels were very low. Those riders that selected the soft compound perhaps thought that the track would stay consistently wet, as the soft option should be better in such conditions. On the other hand, had the rain stopped completely, those riders that selected the harder rear compound would have had the benefit of more consistent grip towards the end of the race as the track dried out.”