The official line by Pirelli is that the tyre blowouts that ended the race of Max Verstappen and Lance Stroll at Baku washy because of a production fault, wear nor delamination. Instead, the investigation revealed that the blowouts happened because of a circumferential break on the inner sidewall of the tyres. This break wasn't a result of debris something Pirelli had indicated originally.
"This analysis also took in the tyres used by other cars in the race, which had the same or a higher number of laps on them compared to the ones that were damaged," Pirelli said in a statement.
"The process established that there was no production or quality defect on any of the tyres; nor was there any sign of fatigue or delamination. The causes of the two left-rear tyre failures on the Aston Martin and Red Bull cars have been clearly identified. In each case, this was down to a circumferential break on the inner sidewall, which can be related to the running conditions of the tyre, in spite of the prescribed starting parameters (minimum pressure and maximum blanket temperature) having been followed," the official F1 tyre supplier said.
Since neither a puncture caused by debris was on the table nor were there any production issues, so what happened. There was a theory running about in the paddock that Red Bull and Aston Martin played around with the tyre pressures. When the tyre is first fitted to a car there is a requirement of minimum tyre pressure, but once it on a car out on track, there is no minimum requirement. This opens up a window for the teams to reduce the pressure, but this also causes the tyres to be under more stress especially on a track like Baku which has the longest straight-line segment of the year with cars at full throttle for a long period.
"As a result of this analysis, Pirelli have submitted their report to the FIA and the Teams. The FIA and Pirelli have agreed to a new set of protocols, including an upgraded technical directive already distributed, for monitoring operating conditions during a race weekend and they will consider any other appropriate actions," said Pirelli insinuating something of this sort happened.
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But Red Bull soon after shot out a statement of its own claiming that nothing of this sort happened and in fact during the investigation, it was linked up with Pirelli.
"We have worked closely with Pirelli and the FIA during their investigation into Max's tyre failure on lap 47 of the Azerbaijan Grand Prix and can confirm that no car fault was found. We adhered to Pirelli's tyre parameters at all times and will continue to follow their guidance.
We are grateful that following the weekend's high speed impacts no drivers were injured," said the world championship leaders.
The broader issue is that the cars have become so fast that the current generation of tyres perhaps can't handle them. In fact, technical directives were issued for 2021 which impact the downforce acquired from the floor to slow down the cars in tandem with tougher tyres, something that Aston Martin hasn't been totally happy about.
Additionally, Pirelli being the sole manufacturer of tyres also doesn't help matters as the competitiveness of the teams causes more secrecy which throttles development around such issues. This wasn't the problem back when F1 had Bridgestone and Michelin as tyre partners. In the case of Bridgestone, the partnership with Ferrari was so tight that the rubber was almost custom made for Michael Schumacher's cars that led to new levels of tyre optimisation and knowledge.
