Lack of intermediates worries Vermeulen

For 2007 riders are limited to 14 front and 17 rear tyres per weekend. The restrictions do not apply to wet weather tyres, but intermediates are considered 'slicks' under the regulations.

As teams have to nominate their tyre choices on the Thursday morning before the race weekend, they are unlikely to waste a 'slick' tyre on an intermediate option that might never be required.

"We've got nothing really in-between - there's wets or slicks," Vermeulen told autosport.com.

"Because of this tyre rule, an intermediate is classed as a slick tyre and one of your allocation, so you're never going to say on Thursday morning 'I'll nominate an intermediate', so there's nothing in-between and it's really difficult.

"You can cut your slicks, but they're still very hard. So how do you get heat into them even if you cut them?

"That's the hard thing now with this tyre rule. If the race is iffy tomorrow, you've got wets or you've got dries and the place changed so quickly today, I was shocked."

The rain has fallen in a series of short but heavy showers during qualifying day, rather than a constant downpour, and the track has dried significantly between each cloudburst.