Red Bull Racing thinks it may never have a definitive explanation for what caused Sebastian Vettel's puncture in the Abu Dhabi Grand Prix, after post-race analysis failed to uncover a firm answer.
Although investigations have ruled out a structural failure of the tyre or valve, and Pirelli says it has discovered no proof that debris was to blame, Red Bull Racing suspects that the most likely cause of the tyre deflating was a piece of carbon fibre from another car that Vettel ran over at the first exit kerb.
Red Bull Racing team principal Christian Horner said that analysis work with Pirelli had failed to uncover a definite cause.
"We have worked hard with the full assistance of Pirelli to find an answer, but unfortunately when you are presented with a bag of bits it is almost impossible to come up with a firm answer," he told AUTOSPORT.
"There is nothing on the data to suggest there was anything wrong with the tyre before the start, but when he ran across the kerb on the exit of Turn 1 there was an instant deflation. We believe the most likely cause of this was a foreign object penetrating the tyre, but we may never find the true answer."
Horner dismissed theories that the tyre failure was caused by the inner sidewall getting overheated from exhaust gasses blown on it at the rear of the car.
He also said that on-board footage from Jenson Button's car on the grid, that showed smoke emerging from Vettel's right rear tyre at the start, was not actually rubber but was in fact burning bodywork.
"There was some worn bodywork that got burned, and that gave the appearance of smoke from the tyre after the start," he said.
"Sebastian's start procedure was the same as Mark's, and the same it had been all season. We were also running in the same configuration as before, so there is no reason why we should suddenly suffer a problem."