SHANGHAI Robert Kubica has decided to run with a KERS unit in his BMW Sauber car during Fridays practice ahead of Sundays Chinese Grand Prix.

The 24-year-old Pole, who is far taller and heavier than his teammate German Nick Heidfeld, did not use the Kinetic Energy Recovery System (KERS) at either of the two opening races in Australia and Malaysia.

He and the team said this was because the extra weight of the system, added to the need to reduce ballast, had created handling and tyre-wear problems.

But he said Thursday he was happy to try the system out at the Shanghai International Circuit because it has long straights and may offer advantages in speed and boost that make up for handling.

'We will have to test it and see. For sure we have seen this from our view, especially in Malaysia, but also in Australia, it was an advantage (for Nick),'he said.

'But, running on my car there are some disadvantages that are bigger than for the other drivers, but I hope still the advantage will be bigger than the disadvantage.

'The balance of the car is the issue,' added Kubica. 'We will see -- a lot will depend on that and the grip level.' The KERS device has been introduced to Formula One as an option this season.

It takes energy created in braking and saves it, normally in a battery, to make it available for brief power boosts, one per lap, when selected by the driver.

The system adds weight to the car and only the Ferrari, McLaren, Renault and BMW teams used it at the opening races.