Pirelli now believes that the tyre failures suffered by Lewis Hamilton and Carlos Sainz in Formula 1’s Qatar Grand Prix were not caused by debris from the mirror run over by Valtteri Bottas.
The Mercedes and Ferrari drivers both suffered front left failures within seconds of each other during the Qatar event, which also coincided with a moment when parts from Alex Albon’s discarded mirror were spread across the start-finish straight after being run over by Bottas's Sauber.
It was initially suspected that the two punctures were the result of the drivers running over mirror debris, but more detailed analysis over recent days appears now to have ruled that out.
Pirelli F1 chief engineer Simone Berra says that detailed investigation work has now commenced at its Milan base to get to the bottom of what happened, and work out exactly what did cause the issues.
However, early analysis of telemetry that has taken place in the days after the race has already shown that both drivers were suffering pressure losses before they went past the mirror debris.
Asked by Motorsport.com about the latest on the investigation, Berra said: “Looking at the telemetry data, obviously we noticed that the pressure loss was before Bottas hit the mirror on the straight.
“So basically, these punctures happened on other places of the circuit, because of other debris, or for other reasons."
The Qatar tyres only arrived back in Italy a few days ago and work on looking into what happened began on Thursday.
Berra added: “We are going to do all our usual checks – looking at a [cross] section in the tyres, checking the sidewall, doing some fatigue life, and residual life in terms of fatigue resistance.
“We are doing all these tests, and then obviously we will inform the FIA and the teams on the outcome. But for the moment, we still don't have any results.
“Everything is still ongoing. Probably we will have something at the end of next week, but most likely in two weeks there will be a proper and complete overview of what happened.”
Pushed on whether there was any early indication if the failures were caused by the Qatar kerbs or another piece of debris, Berra said: “This is what we would like to understand.
“Of course, that's important. It's important for the teams. It's important for us. So we would like to go very much in detail to understand if it was debris or not.”
Pirelli’s conclusion about the failures not coming from mirror debris match what Mercedes has now also suspected happened.
Speaking earlier this week, Mercedes trackside engineering director Andrew Shovlin told the team’s regular post-race video debrief: “We have the video data and we can see exactly when that mirror got smashed, when it got broken into a lot of pieces.
“We have also got the on-car data, and we are measuring the pressure in the tyres live. Surprisingly, we can see Lewis start to lose pressure prior to the mirror being hit by Valtteri. We would therefore say it is unlikely that it was a debris puncture.
“It does not mean that he did not pick up some debris elsewhere, but we need to wait for Pirelli to do their analysis and their investigations.”
The front-left tyre is put through tremendous forces at Losail, and the lack of degradation meant teams pushed the wear of their rubber to 100% levels – which leaves tyres susceptible to damage.
