MONZA, Italy — Pirelli says that "a highly unusual number of cuts" were reported by the Formula One tire supplier’s engineers at the Belgian Grand Prix, one of which caused the failure on Nico Rosberg’s car.
Pirelli released findings Thursday from its investigation into the incidents two weeks ago.
While Rosberg’s incident occurred in practice, the right rear tire of Sebastian Vettel’s Ferrari was torn to shreds at 320 kph (200 mph) in the penultimate lap of the race.
Ferrari used a single pit-stop strategy which added stress on the tires. Pirelli says the remaining tread thickness on Vettel’s rear tires "was approximately 30 per cent at the time of the failure, making the tire more susceptible to damage from even small pieces of debris."
FIA says it is satisfied with Pirelli’s investigation.