Williams identifies bump that caused Massa/Bottas' US GP failure

Bottas had also changed his gearbox between qualifying and the race because of a damper problem, retired on lap five at Austin while Massa followed suit 18 laps later.

The Finn says the load encountered on a bump on the approach to Turn 11 at the Circuit of the Americas contributed to the failure.

When asked if he was confident Williams was on top of the problem, Bottas said: "Yes, we think so.

"We have found the mechanical issue and we have done modifications to the part which broke down.

"Before Turn 11, that was the biggest bump.

"We saw from the data we have never experienced that much load this year in any place so we don't think it was a batch issue."

The race programme was severely affected by bad weather at Austin, with second practice cancelled and dry weather running limited.

Massa believes the lack of running on Friday contributed to the team not encountering and solving the problem sooner.

"I would say the main issue was the bump on the track and we were a little bit unlucky in a way that on Friday we didn't run," he said.

"If on Friday, it was possible to do the long runs, maybe the problem would have happened already and it would have been OK to fix for qualifying and the race.

"Unfortunately, we didn't run and it was not possible to see this problem in advance.

"But we never had this problem before so I'm really very keen we're not going to have any more."