Aston Martin “surprised” by Pirelli’s claim low tyre pressures caused Baku crashes

2021 French Grand Prix

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Aston Martin CEO Otmar Szafnauer has insisted the team complied with Pirelli’s tyre pressure requirements prior to the failure which caused Lance Stroll’s crash in Baku.

Stroll’s retirement on lap 29 was the first of two race-ending tyre problems for drivers during the race. Red Bull suffered a similar failure on Max Verstappen’s left-rear tyre later in the afternoon.

Szafnauer said Aston Martin had co-operated with Pirelli’s investigation and ruled out the possibility their car had contributed to the failures.

“We worked with both the FIA and Pirelli to investigate the root cause and we shared all the data, everything we have,” he said. “There was no car fault whatsoever, the car was completely fine. The tyre didn’t rub, the sidewall didn’t rub. And we were well within the prescribed parameters that the FIA and Pirelli give us.”

Pirelli’s head of motorsport Mario Isola said yesterday the failures had occured because Aston Martin and Red Bull’s tyres were running at lower pressures than they expected. This caused a ‘standing wave’ in the tyres’ sidewalls which caused them to break.

Szafnauer said he was “surprised that was the conclusion”, and insisted his team followed the tyre usage restrictions Pirelli laid out prior to the race.

“We followed all the prescriptions to the letter and we were never, ever under the minimum pressure,” he said. “We had stabilised pressures, they were higher, that’s normal, that’s usually what happens. And the pressures on the grid that were checked were above the minimum.

“I don’t know what their expectations were but I would imagine their expectations are the pressure goes up, it’s exactly what happened with us.”

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Asked by RaceFans whether Aston Martin’s tyres were above the minimum pressure levels at all times, Szafnauer said: “We were there at all times, but during Safety Car periods I think everybody goes below.”

Despite his surprise at Pirelli’s explanation for the failures, Szafnauer is confident his team will be able to pass new tests on their compliance with tyre usage restrictions which have been introduced for this weekend’s race.

“If the prescription or the regulation is that you have to go above a certain running pressure and stay there and have it at the end, that’s exactly what we’ll do,” he said. “So we will follow that.”

Among the restrictions are the minimum starting rear tyre pressures, which Pirelli has increased for the French Grand Prix by 2psi compared to its original level.

“It looks like the pressures are being increased, they were increased last weekend too,” said Szafnauer. “We started off on Friday with a different threshold and then it went up. When it went up, we followed it. And if it goes up again, we will follow it.”

Stroll experienced another tyre failure during last year’s Tuscan Grand Prix at Mugello. Szafnauer said there was no connection between the two incidents.

“We had a significantly different car last year,” he explained. “The only constant is that there, too, we were well within the parameters that were set.”

Formula 1 must take the Baku tyre failures seriously and ensure they have been addressed correctly, Szafnauer added. “It’s a real and serious problem that we’ve got to get on top of.

“I think we were lucky to only damage the car and not damage anything else. We’ve got to make sure it doesn’t happen again.

“Like I say, we will follow the new prescriptions and we will always be within the parameters that both the FIA and Pirelli set for us.”

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    17 comments on “Aston Martin “surprised” by Pirelli’s claim low tyre pressures caused Baku crashes”

    1. Even Max is on record saying all tyre pressure data (during the race, which Pirelli usually doesn’t have access to) has been shared with Pirelli and it is always above the minimum pressure. Same as Otmar.

      For Pirelli to reach a completely opposite conclusion with the same data that tyres were running lower than expected pressure with the same data is really strange.

      1. The word is ‘expected’.
        As AM said everyone knows that pressure goes up with higher temperatures (typical when racing). It’s just that Pirelli expected those pressures to go up even further.

        Pirelli’s expectations were clearly wrong, whatever the reasons for that mistake (less temperature increase, different humidity level, etc).
        It’s unacceptable that they miss it by so much that 2 tyres can ‘break’. One would expect them to have decent curves and build in sufficient buffer for something like that never to happen.

        It would be interesting to see the tyre pressure of all teams compared with Pirelli’s expectations.

    2. Davethechicken
      18th June 2021, 19:40

      Even Max???
      Didn’t realise he was a tyre engineer.
      Pirelli have millions of pounds of equipment and dozens of experts to forensically analyse the failure.
      Max kicks his tyre after the accident.
      Whose conclusions are more plausible?

      1. Davethechicken
        18th June 2021, 19:47

        Above is reply to Sumedh

      2. Your hormones avoided reading it seems.
        Max told us all data was given. He is perfectly able to tell us that.
        Your not.

        1. Davethechicken
          18th June 2021, 21:29

          Are you in a Max worshipping cult?

          1. But on the other side, at least he thinks Ferrari and Haas are a bunch of noobs.

      3. RandomMallard (@)
        18th June 2021, 21:56

        In the same way “Lewis” always notices all the technical intricacies of the Red Bull.

        1. Davethechicken
          18th June 2021, 22:05

          Agreed, they just regurgitate what others tell them. Could that be manipulated somehow???
          Comment on the driving that they know. Not engineering which they don’t.
          Still plenty on here to defend their every utterance.

        2. F1oSaurus (@)
          19th June 2021, 8:28

          @randommallard Technical “intricacies ” like the removal of the tyre warmers? Or like a wing that flexes back on it’s mounts by a large angle?

          1. RandomMallard (@)
            19th June 2021, 9:23

            @f1osaurus Yes those sort of stuff. It would be difficult for him to spot them removing the tire warmers when he’s sat in his cockpit unable to see the Red Bull garage. That is what we’re discussing in this thread.

      4. Pirelli are on record saying they can’t trust data from the teams and that they will only be able to in 2022 when teams use sensors provided by F1. That’s quite a bold statement and they are basically suggesting a cause without any proof instead of admitting they were wrong. Tyres should not blow because of small variances in pressure.

    3. Davethechicken
      18th June 2021, 22:04

      Agreed, they just regurgitate what others tell them. Could that be manipulated somehow???

    4. Pirelli’s head of motorsport Mario Isola said yesterday the failures had occured because Aston Martin and Red Bull’s tyres were running at lower pressures than they expected. This caused a ‘standing wave’ in the tyres’ sidewalls which caused them to break.

      I understand the term “standing wave” to indicate an oscillation was occurring, which probably does happen, but was this oscillation unique or normal? I suspect it was more normal than unique.
      One of the functions of a shock absorber is to damp the oscillation of a car after it has hit a bump on the road. It is very normal for a car to hit a bump while being driven, although hitting something bigger like the kerb is more unique than normal. When you drop a tennis ball it bounces. The same happens when your car hits bumps on the road, the car wants to bounce too. After the energy inflicted upon the car from the combination of speed and the bump in the road is absorbed by the suspension and the tyre (“tyre” as in “tyre wall”?), that absorbed energy has to be released, and but for the shock absorber, that energy absorbed by the springs and the tyres would be dissipated by making the car bounce, i.e. there is an oscillation. So the shock absorber attenuates the tendency of a car to bounce after it has hit a bump. I’m sorry, I’ve forgotten most of my mechanics stuff (the engineering mechanics, not the people that fix the car), but aren’t things like moment, mass, elasticity, etc involved?
      Also, how does the speed related increase in loading on the rear tyres from the rear wing affect the tyres? F1 is bringing in new tests to insure the rear wing supports aren’t flexing “too much” at high speed. The reduction in wing pitch of the wing under the old tests, besides reducing drag, would have also reduced the load on the rear tyres. Is it possible those tyres that blew out failed because the load on them was too much? Lance’s tyre failure happened at around 280 km/h. Max’s tyre also failed at high speed (not sure what speed it was). Maybe F1 needs to go the other way and ask the teams to make sure the wing supports can flex at high speed so as to reduce the load on the rear tyres.
      It is a pity Pirelli weren’t a little more informative about what the unique elements were which contributed to the oscillation that was destructive to those particular tyres compared to what the normal elements are that are inflicted upon an F1 car tyre. For example did the hardness of the suspension or the new rules regarding the flexing on the rear wing of the car contribute to these failures?

    5. I do think Max contributed, a little, to the failure, he was running hot laps, which weren’t really necessary. Stroll’s tire had already exploded, Hamilton was longer on the set, just go slowest you can go to the finish.

      Pirelli tire construction should still not fail of course. Ideally it’s a tire that indicates wear and beyond significant surface wear should be the first failure mode to tire failure. Other failures should be designed with higher safety factors..

    6. Warning: Conspiracy theory ahead…

      Might some teams be using a form of “deflator” on their wheel hubs that lower the pressure during the race but allow the pressure to meet the minimum values when stopped? E.g.
      1. A vacuum-filled flexible metal cylinder around the hub that deforms when under sudden extra pressure to allow the tyre to deform far more when riding bumps, or
      2. A sprung section of hub that creates more volume but that only opens up when the nut is on, or
      3. A centripetal-driven component in the hub that moves to lower the pressure in tyres when turning at speed, or
      4. Something clever that might actually work :)

      These devices could provide better performance and could be tuned by which wheel nuts are fitted so as to increase the effect during qualifying – where tyre failure is very unlikely – and decrease it during races to a point where the team has determined has a small safety margin to see out the race, but which might not always work e.g. Baku.

      Like our friends at Ferrari with their engines and fuel-flow, the teams might now have been found out. The FIA and Pirelli would not want to publicly call them out as cheats but, by implementing extra checks, they’re now going to be prevented from “creative” interpretations of the tyre pressure rules.

    7. Borderline ridiculous and dangerous company this Pirelli. Would never buy one of their products.

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