The 2021 Grand Prix of Azerbaijan was a rollercoaster ride. Unusual podium results, red flags and a rare mistake from Lewis Hamilton were some of the key highlights of the race. But there were two incidents that brought Pirelli, the tyre manufacturer, into question.
Lance Stroll mysteriously blew out his left rear tyre at the end of lap 30 on the final run to the start/finish straight. He was at a high speed section of the circuit coming full throttle out of turn 18. He lost the rear left tyre without any prior warning and went straight into the wall. Even the sensors on the car could not relay any information about the failure to the trackside engineers. Then, Max Verstappen blew out his left rear tyre at the end of lap 46 on the start/finish straight and yet again, no sensors on the car could pick out any signs of warning of failure. Both incidents had tyre blow outs on a similar tyre age. The initial conclusion set by Pirelli was that debris on the track created a puncture in the tyres, which resulted in the tyre failure.
But after a deep investigation with the FIA, Pirelli concluded that the tyre failure was a result of a circumferential break on the inner sidewall. Pirelli had changed the minimum tyre pressure requirement on the rear tyres previous to the Azerbaijan GP but links of the failure to the tyre pressure change is still unclear. All the teams had adhered to the prescribed running parameters of maintaining minimum pressure and maximum tyre banket temperature. Pireili had also stated that the tyre life of the C3 hard compound tyres would have a running life of 40 laps. Most of the drivers, including Max and Lance, were under the 40 laps limit. Only Lando Norris of McLaren Racing had completed the highest of 41 laps on the hard compound tyres. While the teams were initially pointing towards a tyre failure, Pirelli’s initial argument was that a tyre failure would give prior notice or signs and only in cases of debris related puncture does a tyre blow out without any warning. However, with the cause finally revealed, Pirelli is taking measures to mitigate this issue.
Results of this analysis have already been sent to the FIA and the Formula One Teams. FIA and Pirelli have already agreed to sign a new set of protocols and an upgraded technical directive has been distributed to monitor tyre operating conditions during a race weekend. Pirelli and the FIA are also open to other appropriate actions to nullify such incidents in the future.