Pirelli has carried out an extensive investigation following the tyre incidents during the Belgian GP.

Its main conclusions, as presented to the FIA, were :

-       Tyres used by different teams during the race were examined by cutting sections through the tyre, none showed any signs of internal delamination (hence fatigue).

-       Tyres used by different teams during the race were run on a test rig and were subjected to a representative race duty cycle, again none showed any signs of internal delamination (hence fatigue).

-       A highly unusual number of cuts were reported by Pirelli engineers during the Spa weekend, one of which reached the belt and caused tyre failure on Nico Rosberg’s car.

-       Microscopic examination was conducted on sections taken through some of the cuts found in tyres used by different teams in the race, the results showed one other case where the cut had reached the belt but without causing failure.

-       The remaining tread thickness on Sebastian Vettel’s rear tyres was approximately 30% at the time of the failure making the tyre more susceptible to damage from even small pieces of debris. 

The FIA is satisfied with the thoroughness of the investigation and Pirelli’s conclusions as to the reasons for the tyre failures in Belgium.

Based on this, the FIA is willing to consider any safety recommendations made by the tyre supplier for the Italian GP and for the remainder of the season.