Pirelli claimed on Tuesday that the tyres used at Silverstone during the chaotic British Grand Prix last Sunday would not have suffered spectacular blow-outs had they been used in the correct way.
As predicted in The Daily Telegraph yesterday, Pirelli will make immediate changes for the German Grand Prix this weekend, providing its -proto-type Kevlar-belted rear tyres for the race at the Nurburgring, before switching to a "new range" of 2012 structures with 2013 compounds from Hungary onwards.
However, after two days of stinging criticism, both of Pirelli and the sport in general for having allowed itself to get into this mess, the Italian manufacturer came out fighting last night, claiming that its 2013 tyres "do not compromise safety if used in the correct way".
After "exhaustive analysis" of the tyres used at Silverstone, Pirelli concluded that a combination of factors had been to blame. Perhaps most interesting is that all the cars affected had rear tyres that were mounted the wrong way around, placing the metallic belts of the tyres in the wrong rotational direction and ensuring that, under Silverstone's high loads, they entered the contact patch of the tyre with the leading edge pointing.
"The tyres have an asymmetric structure, which means that they are not designed to be interchangeable," Pirelli said in a statement. "The sidewalls are designed 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 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."
Pirelli added that it was not blaming teams for having switched the tyres, describing it as a "practice that was underestimated by everybody, above all Pirelli, which did not forbid this". However, it did accuse the teams of ignoring its advice concerning tyre pressures at Silverstone, which it described as "excessively low or in any case lower than those indicated by Pirelli".
The other factors behind the -failures, according to Pirelli, were extreme camber angles and Silverstone's kerbs, which it described as "particularly aggressive on fast -corners". Pirelli added that it was essential that henceforth tyres are "regulated and carefully controlled by Pirelli".
This would require "real-time data from the teams regarding fundamental parameters such as pressure, -temperature and camber angles". Teams will no doubt discuss these requests at a meeting of the Sporting Working Group today. Paul Hembery, Pirelli's motorsport director, concluded: "The 2013 range of tyres, used in the correct way, is completely safe. While we wait for a change in the rules, we will introduce tyres that are easier to manage."