Bridgestone airs groove concerns

Television images of cars in parc ferme at the end of a race regularly show grooves that appear to have worn down completely to the point where the tyre is slick. In fact, the driver has often been off the racing line on his slow-down lap and the tyres have picked up discarded rubber, or 'marbles,' which fill up the grooves. When this debris is scraped away, the groves are still apparent.

The Canadian Grand Prix, however, heightened Bridgestone's concerns, when pit stops revealed Michelin cars with what appeared to be well-worn grooves at a time when the drivers had not been off-line. Michelin-shod teams often elect not to change the fronts because retaining scrubbed tyres solves understeer problems caused by graining.

Suganuma said: "Bridgestone's tyres don't suffer from this problem which is why it is rare to see a Bridgestone team using scrubbed tyres. Personally, I think that if the front tyres are worn so much that you can't see the grooves, then that is against the spirit of the regulations."

The FIA, meanwhile, has always taken the stance that it will closely monitor tyre performance to ensure that no company is constructing a tyre that gives a performance advantage when in a worn condition. It can do this by monitoring lap times while factoring in reducing fuel loads.