Pirelli has revealed that an inspection following the Formula 1 Azerbaijan Grand Prix of the tyres on Lewis Hamilton’s Mercedes revealed a cut to the right-rear tyre.
Max Verstappen and Lance Stroll both crashed out of the event with apparent tyre failures on the high-speed front straight.
Both incidents occurred with approximately 30 laps on the hard compound tyres, while Pirelli rated them for a life of 41 laps.
Following the race, Sebastian Vettel led calls for an investigation into both crashes, suggesting the incidents occurred in “probably the worst place of the year you want to have this”.
Both Stroll and Verstappen had failures with the left-rear tyre, with Pirelli’s head of F1 and car racing, Mario Isola, revealing cuts were found in Hamilton’s right-rear.
“We need to clearly establish the facts behind the incidents involving Lance Stroll and Max Verstappen to fully understand what happened,” he said.
“What we can say for now is that there was also a cut found on Hamilton’s tyre and that it’s the rear-right tyre that actually works harder than the rear-left here.
“No warnings or vibrations were detected and none of the other tyres of a similar age or older showed any signs of excess wear.
“So we can not exclude that the damage was caused by an external factor, although these things shouldn’t happen and we can understand the need for answers.”
For Verstappen, there was no warning before he was pitched into the barrier on the pit straight at top speed.
“I didn’t feel anything strange with the car and then suddenly the left rear went and I was in the wall quite hard,” he said.
“It’s not a nice place to crash and we don’t know the exact cause yet, I’m sure it will be fully investigated.”
At that point the incident had notable championship implications, with Verstappen leading both the race and the championship at that point.
With the Dutchman out, Hamilton moved up to second behind Sergio Perez as the race was red flagged, a result that would have seen the Englishman reclaim top spot in the title race.
However, he then locked up and slid off the road at the standing restart on Lap 50, effectively negating Verstappen’s demise.
Teams had access to the three softest compound tyres in Pirelli’s range in Azerbaijan, the same compounds as those used in Monaco, and a step softer than used last time F1 visited Baku.
Under the red flag, Mercedes opted to change Hamilton’s front wing as it carried damage to its leading edge – potentially caused by a tree branch which fell onto the circuit in the early stages of the race at Turn 15.
The incidents for Stroll and Verstappen also littered the circuit with debris, while Daniel Ricciardo was tagged at Turn 2 at the restart causing damage to the McLaren’s diffuser.