Pirelli explains the problems encountered at Silverstone

After the problems encountered at Silverstone during the British Grand Prix, Pirelli analyzed both the tires that exploded and those that did not encounter any issues, allowing the Italian manufacturer to determine the causes of the multiple blowouts.

The Italian manufacturer has identified several causes and decided to implement multiple solutions, in agreement with the FIA, as explained in the statement released today. While Derek Warwick – head of the British Racing Drivers Club, owner of the Silverstone circuit – believed that the circuit’s curbs could not have caused such problems, Pirelli seems to think otherwise and cites this as one of the causes of the issues seen at Silverstone.

« After an exhaustive analysis of the tires used at Silverstone, Pirelli concluded that the causes of these problems were primarily due to a combination of the following factors:

1) The rear tires were mounted incorrectly: in other words, the right tire was placed where the left should have been and vice versa on the cars that experienced problems. The tires provided this year have an asymmetric structure, meaning they are not designed to be interchangeable. The sidewalls are designed to handle different loads on the inner and outer parts of the tire. Therefore, swapping the tires affects how they function under certain conditions. Specifically, the outer part is designed to withstand very high loads generated in the corners on a demanding circuit like Silverstone, with fast left-hand turns and particularly aggressive curbs.

2) The use of very low tire pressures, sometimes even lower than those recommended by Pirelli. Under-inflating the tires means that the tire is subjected to even more challenging conditions.

3) The use of extreme camber angles.

4) Particularly aggressive kerbs in fast corners, such as at turn 4 at Silverstone, which was the site of most of the problems. This is where the left-rear tires were affected.

The only problems encountered before Silverstone were delaminations, which is a very different phenomenon. To put an end to these delaminations, Pirelli found a solution by suggesting teams use the tires tested in Canada starting from Silverstone. When this solution was refused, Pirelli found another solution through its testing laboratory, with a different bonding process to secure the tread. So the delamination issue has nothing to do with what was seen in Great Britain.

Following the conclusions of this analysis, Pirelli wishes to emphasize:

1) Mounting tires in reverse is a practice that has been underestimated by everyone: especially by Pirelli, which did not prohibit it.

2) In the same way, under-inflation of tires and the use of extreme camber, over which Pirelli has no control, are choices that can be dangerous in certain circumstances. Following this, Pirelli has asked the FIA for these parameters to be a subject for future and precise analyses. Pirelli has also requested that these rules be verified by a specific delegate.

Pirelli would also like to emphasize that the 2013 tire range does not compromise driver safety if used correctly and meets all the safety standards required by the FIA.

The logical conclusion is that it is essential for the tires with the technical sophistication and performance of the 2013 range to be verified and precisely controlled by Pirelli itself. To ensure the optimal functioning of the tires, the Italian firm would need real-time data from the teams regarding fundamental parameters such as pressure, temperature, and camber angles. Pending new rules that could allow Pirelli access to this vital data for the development and management of these tires, the following measures have been proposed for the upcoming Grand Prix events, in agreement with the FIA, FOM, the teams, and the drivers:

1) The use of the current tire evolution tested in Canada (and proven to be reliable) for the German Grand Prix this weekend. This represents the best combination for the technical characteristics of the Nürburgring circuit. The rear tires to be used for the German Grand Prix, taking place on July 7th, will have a Kevlar construction replacing the current steel structure and the reintroduction of the 2012 belt to ensure maximum stability and handling. Since these tires are also asymmetrical, it will be strictly forbidden to swap them. The front tires will remain unchanged.

2) Starting from the Hungarian Grand Prix, the introduction of a new range of tires. The new tires will have a symmetrical structure, designed to ensure maximum safety even without access to data – which nevertheless is essential for optimal functioning of these more sophisticated 2013 tires. The tires to be used from the Hungarian Grand Prix will combine the characteristics of the 2012 tires with the performance of the 2013 compounds. The new tires will have a structure, construction, and belt identical to those of 2012, which ensured maximum performance and safety. The compounds will be the same as those used throughout 2013, guaranteeing faster lap times and a better usage window. The new specification, as accepted by the FIA, will be tested on track with teams and their 2013 single-seaters at Silverstone from July 17 to 19 during a session with race drivers during the young drivers’ tests. These tests will contribute to the final development of this new range of tires, offering teams the opportunity to make appropriate adjustments to their cars.