By Stephen English

Following a wet opening day of practice for Sunday's Spanish MotoGP at Jerez, world champion Casey Stoner called for changes to the regulations governing flag-to-flag races.

The MotoGP regulations state that races will run in their entirety, without stoppages due to changing weather conditions.

Riders are instead allowed to change bikes during the race, but they must leave the pits on a different tyre combination than they came in with. Therefore, riders entering on wet tyres have to leave on slicks or vice versa.

After two rain-affected Friday practice sessions, Stoner called for the governing body to re-examine this regulation, due to the dangers presented by being on the wrong tyres for the track conditions.

Last year's Jerez race was blighted by a series of crashes after riders started the race on wet weather tyres, only for a dry line to subsequently emerge. The closing stages of the race saw rain return, but if any riders had pitted they would have been forced to fit slicks.

As a result, riders continued on badly worn wet tyres. Among those to be caught out in the closing stages was Ben Spies, who lost a potential podium position.

When asked whether he would be in support of riders being able to change bikes, but keep racing with a new tyre of the same type, the Australian enthused:

"I think it's a very good idea. We've been discussing this all last year-especially after the race last year and I think MSMA [manufacturers' association] have been pushing for this. They definitely need to do something after what happened last year."

When asked whether he thought it was safe to have riders racing on badly worn wet tyres in mixed conditions, Stoner replied:

"If it rains again, like it did last year, you saw rider after rider going down - that's when it starts to get very hairy. You can go out in those conditions and destroy a wet tyre but it's still too wet for slicks. We need to be able to change to another set of wets particularly in those circumstances."