Kubica unhappy with car balance

Robert Kubica says there is still a lot of work to do before he feels comfortable with his car after struggling during practice for the Chinese Grand Prix

The BMW Sauber driver, still fighting for the drivers' championship, finished down in 12th position, the Pole unhappy with the lack of grip and the balance of his car.

"As usual on Friday, we did the tyre evaluation and worked on the set-up of the car," said Kubica, who is 12 points behind Lewis Hamilton in the championship standings.

"We tried all kinds of different things, but I'm not happy yet with the balance of the car, and the overall level of grip is poor.

"We have to analyse the data carefully to make the right changes for tomorrow. There is still a lot of work to be done."

Teammate Nick Heidfeld had a more encouraging day, the German posting the ninth fastest time.

"In the second session especially I was quite happy with the long runs, as well as with the single laps," he said. "We have done quite a lot of set-up changes in the course of the day and during both sessions.

"Not every step was one in the right direction, but we understood and learned a lot."