Romain Grosjean's Sochi crash broke seat of his Lotus

Patrik Lundin/Sutton Images

Romain Grosjean has revealed his heavy crash at the Russian Grand Prix broke the seat of his Lotus.

Grosjean spun out of the high-speed Turn 3 horseshoe on lap 11, ploughing heavily into the outside barrier. The Frenchman paid tribute to the safety of F1 after the shunt, which he walked away from unharmed, and did so again ahead of this weekend's United States Grand Prix.

"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, so a little thank you to Bell, HANS, Enstone, the circuit, the FIA and the marshals and medical personnel. Also a big thank you to my crew who had to pick up the pieces and put the car back together."

Technical chief Nick Chester thinks the crash was caused by a loss of downforce.

"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."