Pirelli motorsport boss Paul Hembery says Sebastian Vettel's tyre blowout at the Belgian Grand Prix was unrelated to Nico Rosberg's FP2 failure and instead down to how long the Ferrari driver stayed on his tyres.
Vettel's right rear exploded on the penultimate lap shortly after the flat-out Eau Rouge section, prompting a furious reaction from the four-time world champion towards F1's tyre manufacturer. It came just two days after Rosberg suffered a tyre blowout in FP2, which Pirelli put down to an "external cut" possibly caused by part of the Mercedes' bodywork.
Vettel was attempting a one-stop strategy to beat the charging Romain Grosjean to the final spot on the podium when his tyre failed on its 27th lap.
Asked what we would say in response to Vettel's comments, Hembery said: "It's wear ... The end of wear life. When you do that, any tyre in the world that you have, when it gets to the end of its wear life you're going to have a problem."
Though Pirelli had estimated wear life at 40 laps, Hembery says there are plenty of factors which can change that figure. He said the company had been expecting teams to opt for a two- or three-stop strategy, as every other driver did.
"It was more we thought the strategy was going to be based on two or three stops, as you saw the majority did, but they clearly felt they could make it work on the one stop. The wear life was indicated at around 40 laps, but that's an indication and race conditions can change that. Some factors involved in racing mean that's sometimes it's not precise data. Other teams were clearly taking it in a different direction."
When asked if Pirelli had let the teams know the tyre wear would be around the 28-lap mark, he replied: "It was not something I knew about."
Vettel's anger came after he raised concerns to the FIA on Friday following Rosberg's failure. Hembery said there was no similarity in the failures suffered by the two German drivers.
"No, absolutely nothing. Rosberg was an external cut, this was pure wear. And if you look at the images the actual carcass is actually intact - it was a wear issue, the second one, and Friday was a cut."