Will Jordan turn their back on Bridgestone?

Ralf Schumacher's Williams scored Michelin's first Grand Prix win at San Marino last weekend in only the fourth race since the French company returned to Formula 1 and it is apparent that in certain circumstances the new entrant’s tyre is faster.

As the threat from Michelin increases, Frentzen believes that Jordan and other Bridgestone-shod teams could end up suffering as the Japanese firm struggles to meet the needs of the top two.

"Bridgestone should be nervous," said Frentzen, "and I think they should be worried about Michelin. I think they're finding it difficult to find a tyre that suits both of the top teams [McLaren and Ferrari]."

Bridgestone is set to introduce a new tyre format for next weekend's Spanish Grand Prix which includes a softer rear compound and a wider front tyre. Teams tried the new rubber at Silverstone on Thursday with the McLarens of Mika Hakkinen and David Coulthard topping the times, Jordan are to test the new tyres again on Friday.

So far, Frentzen has been less than impressed with the new format and although he has not yet run with the wider front tyres, the softer rear rubber did not suit the German's Jordan Honda.

Bridgestone still has the overall upper hand and has dominated the top positions in both qualifying and races this year. However, the Japanese firm could be compromised by supplying both Ferrari and McLaren, while Michelin can concentrate on its sole front-running team, Willliams by supplying tyres best suited to the Grove-based team.