Tyre failure caused Baku blowouts — not debris, says Pirelli

The tyre blowouts that pitched Lance Stroll and Max Verstappen into the wall at more than 200mph were the result of a break in their tyres, Pirelli has said after an investigation into the Azerbaijan Grand Prix crashes.

It has rowed back from its initial assessment that on-track debris was to blame, saying that there is evidence that a circular break on the inner sidewall of the left rear tyres caused them to suddenly fail without warning.

The cause was not a defect, Pirelli says, but the “running conditions” of the tyre, inferring that teams had been racing tyres that were outside the temperature or pressure operating requirements

In a statement, Pirelli said that teams had complied with these limits before the tyres were fitted — as required to do.

It has announced a new set of protocols to monitor the operating conditions at this weekend’s French Grand Prix.

Teams have been suspected of pushing the boundaries of the tyre requirements, in particular by allowing the tyre temperature to drop after measuring the pressure, which could lead to cars leaving the pitlane with tyres at a lower pressure than required — with potential performance benefits.

Red Bull said that it always complied with Pirelli’s requirements.

“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,” said Red Bull