Silverstone: Bridgestone tyres play leading role in the wet

If Juan Pablo Montoya and Williams-BMW won the qualifying battle, Michael Schumacher and Ferrari most certainly won the war. Likewise, Michelin might have ruled the roost on Saturday afternoon, but come Sunday and the all-important race, Bridgestone ran rings round them. What might have happened had Silverstone been dry yesterday afternoon was rendered academic as rain drops fell even as the cars left the starting grid.

Montoya fought tooth and nail with Schumacher for the first 15 laps, though at times his occupancy of first place was tenuous. Even before both drivers switched to rain tyres which were better suited to the greasy conditions on lap 13, the gap between them was never greater than the 1.6 seconds that the Colombian had opened up by the second lap. "In those conditions on Michelin's grooved tyres, the car was great," Montoya said. "It was on the edge, but I like it that way."

It was when he changed tyres that the scope of Michelin's problem became apparent. An excellent pit stop enabled him to open his lead over Schumacher to 5.5sec, and Montoya, in common with all the other Michelin runners except for David Coulthard, switched to "full wet" tyres, with maximum depths tread to squeegee water from the road. Schumacher, like all the Bridgestone runners, fitted intermediate tyres, a kind of halfway house between dry and wet-road rubber. In light rain intermediates should have been better; in heavy rain the "full wets" would be superior. At some stage in the changeable conditions the Michelin drivers should have been at an advantage, but it did not work out that way. In one lap Schumacher snatched back 3.3sec from Montoya, then pushed into a 2.4sec lead a lap later when Montoya slid wide at Abbey Corner.

There is no other part of the racing car's package – be it aerodynamics or engines – that can affect lap times as significantly as the tyres. They may be round, black and boring, but they are crucial.

It was not just the Williams-BMW drivers who struggled. McLaren and Renault had abysmal races, Coulthard, in particular, being obliged to creep around a lap longer than most early on, as his team readied him some intermediate tyres. At one stage the Scot, who went off the road several times, was so slow going into Abbey that it caught out the following Felipe Massa, who had to spin to avoid him.

"I have to say that the intermediates were good in both the almost dry and the wet," Schumacher said. "We have worked very hard on that with Bridgestone and the whole car-tyre package worked well. The real question was when to use what tyre. I have to say I was not really sure, so I must thank Ross for making the decisions for me and making the right one. The conditions were really very tricky, especially as the intermediate tyres started to wear out in the dry." That consistency was the key. At times Coulthard, on his intermediate Michelins, was as quick as the Ferraris. But his tyres were a bit like Topsy, very good in some conditions, but horrid the rest of the time.

"I think the tyre we picked was the best tyre we could put on the car," Montoya said philosophically. "It is the best tyre we have found at the moment in any of the conditions and it is getting better, but it is not there yet." Michelin's motorsport director, Pierre Dupasquier, defended his products. "Our intermediate tyres have been much maligned, but if you look at the lap times David Coulthard was doing they stood up very well." Maybe so, but Coulthard was the only one to use them, and when it mattered the Bridgestones performed better.