Petrov changes car after Sepang crash

The Renault driver car's had to be sent back to the factory after the Russian hit a big bump when trying to return to the track at Turn 8.

Petrov will be using chassis #1 in this weekend's Chinese Grand Prix, with his Sepang chassis expected to be used again in Turkey.

The Russian insisted that tyre marbles on the racing line were to blame for his off-track excursion.

"We have so much rubber outside the racing line, but also on the track, on the racing line," he said on Thursday in Shanghai.

"You can see on the TV that I didn't go wide at Turn 7, I didn't even touch the kerbs, but then the car picked up the marbles and I had more and more understeer, and I slowed than and decided that since I'm not making the corner to go wide, because it's safer and didn't want to kill the front left tyre.

"I decided to come back to the track and I knew it was a big kerb. I was not expecting such a big jump."

Petrov said he didn't have any pain despite the big jump, and admitted he was very disappointed to have to retire.

"I was just disappointment. I don't have any pains, nothing. I was just very disappointed. I was not expecting to fly like that."

The accident broke the Russian's car steering column, meaning he could not steer his Renault afterwards.

He admitted he was lucky not to crash.

"I was lucky because my car continued to go straight rather than left or right. Otherwise, you can imagine if the car goes to the right I would have crashed two times harder, so I think I was a little lucky."