BMW Sauber have confirmed that only one of their cars will run the new KERS energy recovery system at this weekend's Australian Grand Prix

Speaking on Thursday, team boss Mario Theissen said that Nick Heidfeld will run with the system - which despite its introduction this year is not mandatory - but that Robert Kubica will not.

Polish driver Kubica is taller and heavier than his German team-mate, meaning that the added weight of the KERS system could leave him at a performance disadvantage.

Teams use ballast, which can be distributed around the car to find the ideal balance, to bring a car up to the minimum weight of 605 kg.

However, bigger drivers have even less of this at their disposal if their car has KERS on board.

Heidfeld will therefore have the power advantage afforded by the system, which stores energy dissipated by a car's brakes and offers it as a boost.

Warning

Theissen voiced the warning that taller drivers would be handicapped because of KERS and called upon the FIA to increasing the minimum weight.

"It is a concern. Having KERS on just one car indicates already that it is not a KERS (reliability) issue," he said. "KERS is ready to race and I'm sure our KERS is on the light side.

"It is a regulatory issue which penalises big drivers and so we have to make sure that each driver gets the best package at a race depending on the track characteristics. We will have to decide on a race by race basis."

Anxious to give themselves every chance of benefiting from the new system, some drivers have lost weight during the off-season.

Former world champions Fernando Alonso and Kimi Raikkonen having both shed around three kilograms in order to lessen the disadvantage.

"It is something you must do because the device is quite heavy," Alonso said. "The ballast we had last year, you were able to move it to set up the car.

"This year it has nearly disappeared."

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