Romain Grosjean's Russian GP crash broke his F1 car's seat

The Lotus driver lost control through the fast Turn 3 with his car ploughing into the outside barrier - but he escaped unhurt.

Ahead of next weekend's United States Grand Prix, Grosjean said: "I'm feeling pretty good, especially considering the force of the impact.

"I broke my seat! It was my biggest impact for quite a while and when I knew I was going to hit the wall I took my hands off the wheel, closed my eyes and braced myself.

"It's a testament to all the safety inherent in the car and the other safety devices.

"Also a big thank you to my crew who had to pick up the pieces and put the car back together."

Technical director Nick Chester said investigations suggested the crash was caused by a loss of downforce and not mechanical failure.

"There is no indication in the data and in the parts that anything broke and subsequently caused the accident," said Chester.

"It isn't easy to draw conclusions in any accident investigation but it looks like Romain was maybe a little bit close to the McLaren and lost some downforce, running out of grip effectively.

"There is nothing that we can see that makes it a car failure."

The cars have been flown direct to Austin, and will not return to Enstone until the end of the season, which means any repairs will be done at the track.

Speaking about the extent of the damage, Chester added: "It is quite significant but still the car stood up well to the impact.

"The right hand side of the car suffered the damage - front and rear suspension right hand side, the nose, the rear wing, crash structure.

"We haven't seen anything however that should stop us getting the car back together."