Pirelli released the results of its technical analysis following the tyre failures of Nico Rosberg and Sebastian Vettel at the Belgian Grand Prix. Both racers were using Pirelli tyres when the incidents happened.
Pirelli took the tyres used the practice sessions and the race and subjected them to several tests. Microscopic analysis and fatigue tests showed no sign of fatigue, meaning the problem is not within the tyre quality.
“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.” said Pirelli.
The tyre company said that the severe number of debris on the track is what caused the failure:
“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.”
Tyre damage from constant cuts is characterized by the loss of tyre pressure. This, Pirelli said, is exactly what happened to Vettel’s tyre at the Spa.
Nico Rosberg’s tyre held up because the usage was less, so the failure was not instant. 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.
At the end of the investigation, Pirelli asked FIA for the circuits to be cleaned to avoid future incidents. FIA then arranged for the tracks to be cleaned from debris and informed the teams of the findings.
Together with the FIA, Pirelli proposes a study to evaluate the way in which circuits can be cleaned most effectively.