Brazilian GP: Renault mandates new alternator for all its F1 teams

With post-race analysis of Webber's broken alternator from last weekend showing a repeat of the problem that put Sebastian Vettel out of the European and Italian Grands Prix, Renault believes the safest solution is to make partner teams Red Bull, Lotus, Williams and Caterham all use the latest version.

Although the change of alternators comes at a crucial time for Red Bull, which is fighting for the world championship against Ferrari in Brazil, Renault is confident that the latest specification is the best solution.

Renault's head of trackside operations Remi Taffin said dyno testing and a detailed analysis of the new alternator that Romain Grosjean raced for the first time at Austin has given it confidence about reliability.

"We have had no issues at all," he told AUTOSPORT about the new alternators. "We sent the one from Grosjean's car back to France to strip it and make sure that everything is fine. We wanted to make sure we did everything we could do, and that was all fine."

When asked if he was as relaxed as he could be about the alternator situation ahead of such a key weekend, Taffin said: "Yes. I can bet you anyone in the pitlane will tell you they are 100 per cent confident for the race, but maybe you will find some say 99 per cent, and I will say I am 99 per cent for here.

"There is no reason [to worry]. We have plenty of other reasons to have a problem - but not this one."

Grosjean and the two Caterhams were the first to race with the new alternators at Austin and, with them encountering no problems while Webber retired with an unusual early failure with an older version, Taffin said there was no other option but to change over for this weekend.

"We sent back the parts [of Webber's alternator] to our headquarters in France and we actually stripped it and we could clearly see that the problem is the same as we experienced in Monza and Valencia. It was exactly the same failure.

"It is very early in terms of mileage and also early in terms of batch, chronologically speaking, so we have no other choice but to go for the next specification."