You mounted them the wrong way, silly!

After the PR disaster that was the British Grand Prix, where four drivers suffered exploding rear tyres, Pirelli has explained its theories on why things went wrong, which largely reads as “it’s not our fault!”.

According to Pirelli four main factors caused the issues and just wait until you read the first one! These factors have been outlined in an article published to the Pirelli website (recommended reading) and state:

After exhaustive analysis of the tyres used at Silverstone, 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.

On first reading mounting the tyres around the wrong way is totally at odds with the professionalism of F1 pit crews. Although, it’s worth noting most teams often deliberately switch the tyres around in the search for more consistent wear.

If it were a case of amateur hour, it gets worse when Pirelli later on says, “Mounting the tyres the wrong way round is a practice that was nonetheless underestimated by everybody: above all Pirelli, which did not forbid this.”

Yet, Pirelli is also at pains to state: “The 2013 tyres do not compromise safety if used in the correct way.”

Going forward Pirelli will bring modified rear tyres to the Nürburgring for this weekend’s German Grand Prix. They feature a kevlar construction using the 2012 belt. Their sidewalls are still asymmetric, so there can be no funny business with mounting them on the wrong side!

From the Hungarian Grand Prix onwards Pirelli is proposing to use a new rear tyre that will remove the mounting issue by having a symmetrical sidewall construction. The rest of the structure and belt will be as per 2012-spec, but they will use 2013 compounds which offer faster lap times and a “wider working range”.

The FIA has agreed that the new tyre range can be tested during the young driver test scheduled for Silverstone on 17–19 July.

And just in case you thought Pirelli might have been putting the blame on the teams, well, they’re not. Paul Hembery from Pirelli issued a further statement which reads: