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Pirelli have offered their thoughts on the marred British Grand Prix with six tire failures on Sunday. As teams, fans and the FIA were all looking for explanations, Pirelli reserved their comments until a full investigation was completed. Pirelli has concluded that the causes of the failures were principally down to a combination of the following factors:

  1.  Rear tyres that were mounted the wrong way round: in other words, the right hand tyre being placed where the left hand one should be and vice versa, on the cars that suffered failures. The tyres supplied this year have an asymmetric structure, which means that they are not designed to be interchangeable. The sidewalls are designed in such a way to deal with specific loads on the internal and external sides of the tyre. So swapping the tyres round has an effect on how they work in certain conditions. In particular, the external part is designed to cope with the very high loads that are generated while cornering at a circuit as demanding as Silverstone, with its rapid left-hand bends and some kerbs that are particularly aggressive.
  2. The use of tyre pressures that were excessively low or in any case lower than those indicated by Pirelli. Under-inflating the tyres means that the tyre is subjected to more stressful working conditions.
  3. The use of extreme camber angles.
  4. Kerbing that was particularly aggressive on fast corners, such as that on turn four at Silverstone, which was the scene of most of the failures. Consequently it was the left-rear tyres that were affected.

The only problems that had come to light before Silverstone were to do with delamination, which was a completely different phenomenon. To stop these delaminations Pirelli found a solution by suggesting that the teams use the tyres that were tried out in Canada from Silverstone onwards. When this proposal was not accepted, Pirelli found another solution through laboratory testing, with a different bonding process to attach the tread to the carcass. In Pirelli’s logic, the problem of delamination had nothing at all to do with what was seen in Great Britain.

Pirelli, to their credit, have offered their conclusions which they were careful not to exclude themselves from some of the culpability:

Following the conclusions of this analysis, Pirelli pointed out that:

  1. Mounting the tyres the wrong way round is a practice that was nonetheless underestimated by everybody: above all Pirelli, which did not forbid this.
  2. In the same way, under-inflation of the tyres and extreme camber settings, over which Pirelli has no control, are choices that can be dangerous under certain circumstances. Because of this, Pirelli has asked the FIA for these parameters will be a topic of accurate and future examinations. Pirelli has also asked for compliance with these rules to be checked by a dedicated delegate.
  3. Pirelli would also like to underline that the 2013 tyre range does not compromise driver safety in any way if used in the correct manner, and that it meets all the safety standards requested by the FIA.

The Italian tire maker feels that the tires need to be regulated and carefully controlled by Pirelli itself. In order to ensure the optimal functioning of the tyres, Pirelli needs real-time data from the teams regarding fundamental parameters such as pressure, temperature and camber angles. While waiting for new regulations that would permit Pirelli access, they have offered the following measures for the forthcoming grands prix, in agreement with the FIA, FOM, the teams and the drivers:

  1. The use of the evolution of the current tyre that was tested in Canada (and proved to be completely reliable) for the German Grand Prix this weekend. This represents the best match for the technical characteristics of the Nurburgring circuit. In particular, the rear tyres that will be used at the German Grand Prix, which takes place on July 7, have a Kevlar construction that replaces the current steel structure and the re-introduction of the 2012 belt, to ensure maximum stability and roadholding. Given that these tyres are asymmetric as well, it will be strictly forbidden to swap them round. The front tyres, by contrast, will remain unaltered.
  2. From the Hungarian Grand Prix onwards, the introduction of a new range of tyres. The new tyres will have a symmetrical structure, designed to guarantee maximum safety even without access to tyre data – which however is essential for the optimal function of the more sophisticated 2013 tyres. The tyres that will be used for the Hungarian Grand Prix onwards will combine the characteristics of the 2012 tyres with the performance of the 2013 compounds. Essentially, the new tyres will have a structure, construction and belt identical to that of 2012, which ensured maximum performance and safety. The compounds will be the same as those used throughout 2013, which guaranteed faster lap times and a wider working range. This new specification, as agreed with the FIA, will be tested on-track together with the teams and their 2013 cars at Silverstone from 17-19 July in a session with the race drivers during the young driver test. These tests will contribute to the definitive development of the new range of tyres, giving teams the opportunity to carry out the appropriate set-up work on their cars.

Paul Hembery, Pirelli’s motorsport director, said:

“What happened at Silverstone was completely unexpected and it was the first time that anything like this has ever occurred in more than a century of Pirelli in motorsport. These incidents, which have upset us greatly, have stressed the urgency of the changes that we already suggested – which will be introduced during for free practice in Germany on Friday. We would like to acknowledge the willingness of the FIA, FOM teams, and drivers to act quickly to find an immediate solution to the problem. In particular, the adoption of winter tests, arranged with the FIA, that are more suitable for tyre development and the possibility of carrying out in-season testing will contribute to the realisation of tyres with increasingly improved standards of safety and performance. I’d like to re-emphasise the fact that the 2013 range of tyres, used in the correct way, is completely safe. What happened at Silverstone though has led us to ask for full access to real time tyre data to ensure the correct usage and development of tyres that have the sophistication we were asked to provide and extremely high performance that has lowered lap times by more than two seconds on average. While we wait for a change in the rules, we will introduce tyres that are easier to manage.”

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An F1 fan since 1972, NC has spent over 25 years in the technology industry and as a CTO, he focuses on technology integration in commercial workspace design, AV systems integration, digital media strategies, technology planning, consulting, speaking, presenting, sales, content strategy, marketing and brand building.
  • mini696

    How common is mounting the tyres the wrong way around? That seems unlikely for Formula One Teams.
    I blame the “magic 8” ball. Shake, shake, shake. Swap they tyres around, it wont hurt.

    Why would Pirelli even make tyres in that way? Its not like they need every performance advantage they can get, who are they competing against? The tyre swappers?

    I get the feeling they are blaming anyone but themselves.

    Trying to keep their PR team upbeat and professional.

    Where in actuality… They done stuffed up.

    • Warthog

      Apparently, mounting the tires the wrong way did help the Mercedes performance earlier in the year.

  • Sven

    I’ve heard about that issue (of swapping tyres) before.
    So if the teams did that and the tyres weren’t designed to bear these loads — e.g. the left rear was in fact a stronger one, than the right one was — the teams replaced a strong tyre with a weaker alternative.

    I does not explain the near bursts though.

    But hey, everyone knows, that the right tyre pressure is important on normal road tyres. Underinflation could cause damage, high stress … to the tyre. So why is it common, to underinflate tyres in F1.

    All in all … there may be problems with Pirelli’s tyres, but IMHO also the teams are to blame.

    • mini696

      “So why is it common, to underinflate tyres in F1”
      Simply because it is faster, it gives more mechanical grip, and heats the tyres up faster if needed in qualifying (for example).

  • Warthog

    Here’s a question about the whole “wrong way around” thing….I was under the impression that it was the tire supplier who actually mounted the tire to the teams’ rims. That would mean that if you swapped the left and right wheels, the “outside” sidewall would still be on the outside, and the “inside” would still be on the inside, even with the wheels swapped. The only way to do what Pirellli is suggesting (reversing which sidewall is on the inside/outside) is if the teams (or Pirelli) actually flipped the way the way the tire is mounted on the rim itself. Is this what is happening?

    • F1derbar

      Here’s a good photoessay on the subject – it appears as though the teams all have their own tire guys, rims, etc. and do their own mounting.

      http://jalopnik.com/5922489/the-wheels-and-tires-of-formula-one/

      • warthog

        Okay. Reason I was wondering is because, I think last year people were asking Pirelli to supply an extra set of tires for Q3 so the teams would do more running. And Pirelli’s response was that then they’d have to supply that extra set for ALL the teams, regardless of who made it into Q3, because they supply the tires already mounted (and there’s no telling who will make it into Q3.

    • tom

      They wouldn’t need to remount the tire. All they do is to swap the tire on the left to the right and vice versa. What you described would only be necessary if they wanted the left rear tire to remain in that place instead of simply swapping it with the right rear tire.

      • warthog

        Based on what Pirelli are saying, that wouldn’t make sense: “The sidewalls are designed in such a way to deal with specific loads on the internal and external sides of the tyre.”

        If all you do is take a tire/rim for the right side of the car and put it on the left side, then the outside sidewall is still on the outside.

        Maybe we’re saying the same thing, but to clarify, in order for the intended inside sidewall to be exposed on the outside of the rim, you have to mount it on the rim in a specific way that opposite of what’s intended.

        • MIE

          For that to happen Pirelli would need to make the left hand tyres different from the right hand tyres. Now this may be what they do. However a lot of racing tyres are directional (they have a preferred direction of rotation) and so the inner sidewall of the LHS tyre would be the outer sidewall of the RHS tyre. If the direction of rotation was reversed, then the loads on the tyre would be distributed differently.

          • MIE

            Please ignore the above comment, I posted it before fully reading the article. Pirelli state quite clearly that their tyres are asymmetric.

  • danfgough

    I was waiting for this kind of announcement about the teams using the tyres out of spec. It happened in 2011 when Pirelli complained that a few teams (especially Red Bull) were running extreme camber angles. Its in the team’s nature to find every opportunity to make the cars go faster. Also, lets face it Pirelli have been in the dog house so who is going to get the heat if you try something naughty and it goes wrong?

    Just regarding the ‘who mounts what’ issue it might still be true that Pirelli mount the tyres. In the article above Pirelli say that they had underestimated the effect of this and they didn’t forbid it.