A shock single-brand proposal was put forward by Dorna during September's Japanese Grand Prix 'due to some factories being unable to acquire the tyres that they want for 2008' - but was then withdrawn on October 24.

That withdraw suggested the factories concerned, Yamaha and Honda - originally unhappy at being denied a switch from Michelin to Bridgestone - were now happy with their 2008 tyres and/or with rule amendments to be made for next season.

So what has changed since the single-brand proposal was first made?

A solution was needed to please the factories 'unable to acquire the tyres that they want', and therefore stop the single-brand proposal, while also keeping Michelin in MotoGP. Michelin initially threatened to quit if it lost either the factory Yamaha or Honda teams, but has recently softened its stance.

The compromise reached is rumoured to involve factory Yamaha star Valentino Rossi switching to Bridgestone, but new team-mate Jorge Lorenzo and factory Honda riders Dani Pedrosa and Nicky Hayden look set to stay with Michelin.

Pedrosa (considered as keen as Rossi to switch to Bridgestone tyres) and Honda are thought to have been won over by an increase in Michelin's MotoGP commitment, combined with amendments to the tyre rules which will loosen the new-for-2007 limits.

Instead of selecting 31 tyres (14 front and 17 rear) before the start of each grand prix weekend, riders will be able to call upon 40 tyres (18 front and 22 rear) in 2008, while the tyre companies will also be able to take advantage of extra track time.

"It has been further decided, also for application as from 1.1.2008, that tyre companies competing in the MotoGP class can, prior to the start of the first race of the season, nominate one GP circuit on which they can test for a maximum of 4 days per year, at any time after the GP has been held at that particular circuit. No rider designated by any MotoGP team will be permitted to take part in these tests," read an FIM statement released on Saturday at Valencia.

"Whenever a new circuit is introduced in the MotoGP calendar for the first time or whenever an existing circuit is totally resurfaced, then a tyre test of a maximum of 2 days of duration must be organised at that circuit a minimum of 4 weeks prior to the race," the statement continued. "This test will be open to all tyre and motorcycle manufacturers competing in the MotoGP class, but no rider designated by a MotoGP team will be permitted to take part in these tests."

This extra track time should help keep the tyre competition closer, since there is less chance of one tyre manufacturer being 'caught out' by unexpected asphalt. Tyres are the most important technical component of a racing motorcycle.

Dunlop, the third MotoGP tyre supplier, is currently exempt from the tyre restrictions as it has not yet won two dry (four-stroke) MotoGP races. However Dunlop, which supplies the 125 and 250cc field, is fighting for its MotoGP future as Tech 3 Yamaha looks certain to switch to Michelin next season.