Max Verstappen, Red Bull, Baku City Circuit, 2021

Pirelli’s suspicion falls on debris as FIA promise “thorough investigation” into crashes

2021 Azerbaijan Grand Prix

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Formula 1’s official tyre supplier Pirelli identified debris as a likely cause of the huge crashes Max Verstappen and Lance Stroll suffered yesterday, following a preliminary investigation.

Their failed left-rear tyres and other samples from the race are being sent to Pirelli’s headquarters in Milan by air freight for further analysis.

Verstappen’s wheel was only lightly damaged in his 300kph crash and may offer valuable evidence, Red Bull team principal Christian Horner told Channel 4 yesterday. “The fact the tyre’s still on the rim gives us something to work with,” he said.

FIA Formula 1 race director Michael Masi promised “a full and thorough investigation” will be conducted by the sport’s governing body in conjunction with Pirelli and the teams.

Pirelli’s head of motorsport Mario Isola said he will “push to have a report as a priority before Paul Ricard”, the scene of the next round of the world championship in less than two weeks’ time.

Verstappen and Stroll both suffered failures of their left-rear hard compound tyres around 30 laps into their stints. Several other drivers ran longer stints on the same tyres, notably Lando Norris, whose tyres were 41 laps old when the race was red-flagged due to Verstappen’s crash.

Pirelli’s initial analysis indicated the cause of the crash was more likely to be debris than tyre wear. “Looking at the tyres used in the second stint, for most of the drivers we didn’t find any evidence of anything,” said Isola. “I believe I can exclude that failures were due to tyre wear because it’s not a matter of tyre wear.”

A stress-related failure would be more likely to occur on the outside wheel, Isola added, which at the anti-clockwise Baku City Circuit is on the right-hand-side. “The rear-left tyre is not the most stressed tyre in Baku because, talking about the rear tyres, it’s obviously the rear right,” he said.

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Isola confirmed Red Bull and Aston Martin had “no sign or any warning” of the failures, both of which occured around the fastest point on the Baku track. “They told me there was no warning, no vibration, nothing to think that there could be something in the tyres.”

Max Verstappen, Red Bull, Baku City Circuit, 2021
Report: Why the Azerbaijan GP was stopped for Verstappen’s crash but not Stroll’s
The discovery of a cut on Lewis Hamilton’s left-rear tyre could be a further pointer to the cause of Verstappen and Stroll’s failures. Isola confirmed this was caused by debris, but said there was no way of telling whether or not the damage occured when Hamilton passed through Verstappen’s crash scene.

“The cut on Lewis’ tyre is clearly coming from debris,” he said. “It is clear because the tyre is still in one piece and you can see that the cut is not following any direction. It’s clearly a cut that is coming from outside.”

Speaking on Sunday evening after the race, Isola said Pirelli will consider all relevant information before issuing an update on its investigation.

“It seems that it is a cut due to debris or because, as I said, it’s not the most stressed tyre, we have another cut in the same position. Both the accidents happened on more or less the same part of the circuit and [with] a few laps’ difference [in stint length]. We have other cars with the same number of laps, same tyres without any issue.

“So the preliminary investigation is that it is probably due to an external factor or debris or a kerb or whatever. But I don’t want to jump to a conclusion now because now the plan is to make a thorough investigation and come back with a report to the FIA and the teams that hopefully will be before Paul Ricard.”

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40 comments on “Pirelli’s suspicion falls on debris as FIA promise “thorough investigation” into crashes”

  1. I am a bit reluctant to spin paranoid theories, but is it really a normal procedure that the evidence is being sent to Pirelli’s headquarters instead of some independent FIA-appointed entity ? In the event that it was a structural failure, there would quite some incentive for Pirelli to manipulate the evidence, supposing they thought they could get away with it.

    Pirelli are probably not that dishonest, but I am sure I wouldn’t have liked the MH17 crash investigation to have been conducted by the Russian justice, for instance.

    1. @palindnilap Pirelli have nothing to hide – they produce tyres to the requested specification and don’t seem overly interested in their image as a result, otherwise they would have left the sport after the 2013 debacle (that, it turns out, was a result of the teams deliberately using the tyres against recommended spec)…

      They investigate and report every failure in a fair amount of detail – at the end of the day, it often is damage from an external source that does it, otherwise surely every car’s tyres would have failed, like what nearly happened during the 2005 US GP?

      1. On top of all, that @optimaximal brings up, @palindnilap, what makes you think there even IS an independent/FIA run lab that has all the knowledge and tech to study a tyre?

        I guess if there would arise suspision of anything untowards, they would try to get the tyre to a lab like that (if one is even in existence, I doubt anyone but a competing tyre producer would have one)

        1. Actually, I think they have not and that is why they are handling it the cheap way. I bet it would be very different if there was a death following a tyre blow-up.

          I certainly disagree that Pirelli don’t care about their image. On the other hand, my guess would be that they would stick to wrapping their conclusions in careful wording and would stop short of proof tampering. But my point is, we can’t be sure of that, so it leaves an impression that something is wrong.

        2. I agree. Probably only a competitor of Pirelli would have the forensic capability to study a damaged tyre. Would it be more or less biased than Pirelli’s own assessment?

          Frankly, I see too many improvised tyre engineers and conspiracy theorists, and even if it’s OK to have different opinions, if the attitudes become toxic they need to stop.

          1. Coventry Climax
            9th June 2021, 16:01

            And if the attitude is ‘just sweep it under the carpet’ that has to stop too.
            Point is, that the FIA should bend over backwards to avoid any -repeat: any- doubts regarding such situations, but sofar they neglect to do so, time and again.

  2. May I suggest some more training on English and media for Isola?
    From all people being interviewed on a regular basis, especially one that is often under criticism, Isola is the champion of sounding insecure and hollow with the words that come out of his mouth.

    “Looking at the tyres used in the second stint, for most of the drivers we didn’t find any evidence of anything,”

    “any evidence of anything”?

    “I believe I can exclude that failures were due to tyre wear because it’s not a matter of tyre wear.”

    Water is wet because it isn’t dry

    “The rear-left tyre is not the most stressed tyre in Baku because, talking about the rear tyres, it’s obviously the rear right,”


    Is it just me or does this scream filling sentences with words because you are desperate to push a point but don’t really have much to back it up?

    1. Seems 101 media training.
      Stick to what you know and refrain from speculating.
      And then repeat what you just repeated.

    2. pastaman (@)
      7th June 2021, 12:46

      It’s just you

    3. It’s just you

  3. They should just pay me to do these investigations for them. After 10 years of reading these tyre failures being blamed on ‘debris’, I’m pretty sure I can draft up an investigation report for them.

    1. My thoughts exactly. Running the investigation department must be hilarious. I bet the department reports to the Marketing director.

  4. Here’s the problem with this initial analysis.
    Both crashes were high speed and dangerous and steps will have to be taken to avoid them as much as possible. If they were indeed caused by debris on the track, then the first question on everybody’s mind is why werent those pieces of debris spotted earlier ? And if they were tiny enough to not be spotted through the video feeds from the camera, then can something else be done ? can we have better track monitoring equipment if possible ? etc..
    i think all the stakeholders–drivers, teams, FOM, FIA will have to come together on this and find a way out.

    1. After all these years of tyres that are exploding due to ‘debris’, you would have thought Pirelli could have made the tyres more resistant to ‘debris’.

      1. @paeschli
        Fair point. They should go back and review the process (if there was one) that was designed to make these tyres debris-resistant as much as possible.

        1. What about double chamber tyres.
          Or maybe run flats, if those could be developed for F1 speeds.

      2. RandomMallard (@)
        7th June 2021, 11:51

        @paeschli Part of the rule changes due this year, now next year because of covid, includes covering the parts of the car that fall off most frequently in a membrane that makes them much less sharp for the tires. It is pretty difficult to make a ball of rubber any less resistant to punctures without lining it with metal though I expect.

        1. Coventry Climax
          7th June 2021, 13:09

          There’s so many options beyond steel alone to reinforce tyres. So many types of plastic, kevlar style materials that are lightweight, and very resilient.
          Actually, such materials are already used in normal road tyres, but obviously, there’s a different price/quality/safety balance involved here. For F1 that should be an entirely different balance, like for space travel or the military.
          For an organisation like Pirelli, that says they are professional, you’d say they could have already come up with a solution during the 10 years we’ve had these issues.
          Then the old adagio is: “But Pirelli just makes the tyres the FIA want them to make”. That creates two options: Pirelli says they can do it but -obviously- can’t, or Pirelli is too weak, too unprofessional and too dollar-oriented an organisation to respond as they then should; stick up the third finger of either hand towards the FIA.

          1. Chris Horton
            8th June 2021, 9:59

            Tyres having plastic in the construction is a disaster environmentally. It Should be outlawed.

          2. Coventry Climax
            9th June 2021, 16:18

            @Chris Horton: that may be so, but is besides the point here. Mind you, I’m very environmentally aware. Space travel is quite environmentally unfriendly too, but we do it all the same, with the lucky side of it -so far- that not everyone is doing it.
            For the amount of tyres used -and recollected, not thrown on the pile- in F1, the environmetal issue is neglectable, certainly in the light of in which areas there’s more to gain. Road tyres is a different category, and deals with completely different volumes.
            Let’s not outlaw plastics as such, because in itself, having a product that lasts 50 years is very environmentally friendly. It’s the amount of unnecessary, cheap and therefor ‘throw-away’ products that’s being made and sold to the masses that’s at fault. I’m in favor of a huge tax on plastic articles like e.g. backyard slides for kids – used a year and then discarded. There’s entire shop chains that thrive on selling plastic. That should stop. Tax it. Heavily.
            Something else, but on the same note: If governments were only willing, we’d have laws defining the minimum contents/packaging ratio, for each and every product category. Byebye waste problem. And don’t come up with ‘practical problems’ like what about the elderly, should they be obliged to buy 5 litres of milk at once? There’s always solutions to deal with those situations.

  5. When you watch the front view slow-mo of VER…you can see a bit of debris flying in the distance right when the tyre blows. I know its not what we want to hear but I do suspect it contributed to the crash.

    1. No, the tyre is already gone at that point, those are pieces from his own car, caused by the tyre ripping apart.

  6. I did think the fact that it was the left rear that failed on both cars was a bit odd. You would expect a wear-related failure to occur on the right-hand side for the reasons Isola points out in the article. However, degradation vs. debris are not a binary choice – there could be other factors, e.g. in the tyre construction, that led to the failures.

  7. Rick Howell
    7th June 2021, 11:31

    Bring on a second tyre supplier.. problem solved.

    1. RandomMallard (@)
      7th June 2021, 11:52

      So that they just push to make the fastest tire that doesn’t puncture? That is a problem, because you have to reach that limit first. See USA 2005

      1. USA 2005 was a failure of the FIA as much as a failure from Michelin. Just put a chicane on the problematic corner and voila, we can race with 24 cars.

        1. Coventry Climax
          7th June 2021, 13:17

          Correct, @Patrick. And while we can’t know for sure it is my opinion that if the FIA had not gone for a single supplier shortly afterwards, we would have had tyre evolution all these years and probably much less of these issues.

    2. No, because that will eliminate half the field for victory. One tire will be dominant and then you get the Mercedes thing all over again. No let them all be on equal stuff please. There are already enough elements non driver related that determine who gets a win.

  8. Id expect Pirelli to be pretty quick to blame something else.

    That being said, in this case, given it’s the tyre that’s least loaded, I’d be guessing that there may have been something on a kerb that inflicted tyre damage. They’ll need to look forensically at every part of the track to make sure there’s not a bolt or something jutting out where it shouldn’t be.

    1. Hard to do that, the track’s been reverted to public roads by now…

  9. I have an opinion
    7th June 2021, 12:02

    Pirelli are fairly certain it is the exact same debris responsible for multiple failures at the 2013 & 2020 British Grands Prix, amongst others. They have attempted to trap this pesky debris with orange plastic bags on the latest victim’s wheels.

  10. Nothing ever comes out of these investigations. The facts are that Verstappen and Stroll had the exact same tyre failure at the same part of the track half an hour between each other. So only Stroll, Verstappen and Hamilton run over this invisible debris? The footage is there, Pirelli should watch it back and find this piece of debris and show it to everyone.

  11. Pirelli will blame debris as usual and of course nobody else will now get to view the evidence to prove any different. You can’t have the same people as poacher and gamekeeper. We’ll of course have to take Pirelli at their word until we start to see more tyres explode in some of the hotter races this summer at which point they’ll likely change their tune.

    If it was a kerb or excessive debris I would expect more than 3 damaged tyres in the race and certainly more to have been visible from the practice sessions too.

  12. of course it was, it’s always ‘debris’ and never the fault of the pathetically bad tires F1 has had to put up with the past decade.

    The pinnacle of the sport should not have to put up with the worst tires in all of motor sport. It’s about time F1 had proper racing tires again & if Pirelli are unable to produce that then either allow competition to force development/improvement or if they want to stick with the anti-competition spec tire pathetic-ness then it’s time to let somebody else have a go.

  13. I think part of the problem is the shorter friday training sessions. ‘Long runs’ only lasted about 8-9 laps for the entire field, often not all on race speed. That’s a serious cut in data provided for Pirelli. We used to see stints of 15+ laps, even here at Baku.

  14. If Isola is right, what a coincidence is this for 3 cars that all have this cut after 30laps give or take? I don’t buy it.
    Imo the tyre is punished hard in there and needs harder structure.

  15. One of the Mercedeses had a visibly cut tyre, so this was real

  16. Like @webtel was saying, we have to analyze this beyond Pirelli’s (biased?) investigation.
    Even if it was debris in Verstappen’s case, how about Stroll? Nobody had crashed or lost parts there before him.
    I don’t remember that F2 cars have left anything behind there either. Maybe there were other support races? Or was it Azerbajan bus debris?

  17. It is funny that Bridgestone never suffered from these invisible debris explosions…

  18. Debris again? Lots of debris these days.

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