Pirelli: Analysis is in, Ferrari and Spa to blame

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Pirelli’s official press release regarding the tire issues at the Belgian Grand Prix:

Milan, September 3, 2015 – Following the recent technical analysis carried out on the tyres used at Spa, Pirelli concludes that:

1)The tests carried out by Pirelli on the tyres used at Spa have confirmed the absence of any structural problems. Pirelli has undertaken in-depth analysis on the materials and production processes used, utilising two different methods of tests and checks.

Microscopic analysis, carried out on a large number of the tyres after the second free practice session, showed no signs of fatigue or integrity issues. The same result was confirmed for the tyres used during the race, which were cross-sectioned and analysed in Milan. Some of the tyres used in the race were subjected to a further laboratory fatigue test, passing all the assessments conclusively and confirming that there was no structural degradation or problem on-track.

Since the start of 2015, 13,748 slick tyres have been used: including on especially severe tracks like Sepang, Barcelona and Silverstone. No problems have ever been discovered, underlining the fundamental solidity of the product.

2)The events of Spa can therefore be put down to external factors, linked with the prolonged use of the tyres on one of the most severe tracks of the championship.

The external factors are demonstrated by a total of 63 cuts found in the tread of the Formula One tyres used over the course of the Spa weekend, following numerous incidents that took place during the support races before the Formula One grand prix. In the previous 15 events (10 races and five test sessions) an average of only 1.2 cuts per event were noted. All this indicates an anomalous amount of detritus on the track in Spa, with a consequent increased risk of encountering a foreign object.

If even a small piece of debris – made of carbon or any other particularly sharp material – penetrates and cuts the various structural parts of a tyre (which is obviously subject to high-speed use, and more susceptible if used for a prolonged period) without penetrating the actual structure, this can cause a failure that is different to that found in the event of a normal puncture, which is characterised by a loss of tyre pressure. And the former was the type of event seen on Sebastian Vettel’s tyre at Spa.

As for Nico Rosberg, in whose case the tyre usage was less, the tyre held up – as the footage clearly shows – and the failure was not instantaneous. For four corners previously, an element of the internal structure of the tyre was visible, coming out of the tread pattern. This highlighted the existence of the damage and the consequent start of the tyre’s attrition.

Throughout the Spa weekend (including practice, qualifying and the race) cuts caused by debris were found on the tyres of other drivers, which damaged the construction but did not cause any failures.

3)At the end of qualifying on Saturday at Spa, following the exceptional number of cuts noted to the tyres, Pirelli pointed out the condition of the circuit to the FIA and asked for it to be cleaned, as well as for the teams to be told. The FIA reacted promptly in arranging for the track to be cleaned and advising the teams.

Together with the FIA, Pirelli proposes a study to evaluate the way in which circuits can be cleaned most effectively.

-end-

Ultimately the circuit was causing more damage to the tires than other circuits on the calendar and Ferrari’s decision to run much longer on a set of tires on a circuit that was very abusive to tires caused the incident.

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Alianora La Canta

If there was no fatigue on the tyres, how can the problem be wear-related (i.e. how is it Ferrari’s fault for running the tyres long)? Extra detritus may be the reason for the problem (and one should probably point to the drivers for generating it), but detritus can cause tyre punctures on any lap. So it doesn’t really get Pirelli off the hook as completely as the press release may sound. It just means that it has plausible deniability in this instance – attached to a tendency to blame the wrong target even when it doesn’t need to blame itself.

MichaelB

The thinking is that a more worn tire is more susceptible to a blow out due to a puncture.. Less material means that debris doesn’t need to puncture the tire as deep for failure to occur… A newer tire is more resilient than an older tire, and since Seb was running on tires older than everybody else the risk was greater.. No mention of the impact of the drivers creating a new racing line outside the marked track limits at Radion though… I’d be surprised if there wasn’t more debris in the area where the drivers chose to run –… Read more »

Negative Camber

That’s exactly the implication the presser seems to be suggesting.

MIE

Both Sebastian and Nick insisted that they had not gone off the track.

I think that their definition of the track is different to mine.

Paul KieferJr

I should also point this out: It’s Pirelli’s tire that got damaged, and it’s Pirelli that tested the tire. This alone introduces a bias. After all, if you discovered that your tire was at fault, would you tell them? No, I’d rather have an independent person without a dog in the hunt one way or the other do the tests and deliver the results to the general public. Then we’d know for sure how things went wrong.

MIE

Who would you suggest? Who else has intimate knowledge of the construction of the tyres concerned and how they are expected to perform. Also if any changes are required it is Pirelli who needs to understand the failure mechanism so that they can correct for it. An independent test house may eventually come up with the results, but possibly not for many weeks. The Italian authorities took a similar view to you in the wake of Senna’s fatal crash. Williams were not allowed access to the wreckage. It took many months before the official investigation was concluded. In the meantime… Read more »

xorpheous

Sign on Pirelli’s hauler…