This weekend's sixth round of the 2009 MotoGP World Championship, at the Circuit de Catalunya, will be the first this year to feature asymmetric Bridgestone rear slicks.

"Catalunya is an important event for us this year because we are introducing our asymmetric tyre," confirmed Bridgestone's manager of motorcycle sport Hiroshi Yamada. "This is something that we had always planned to do since we were appointed as Official Tyre Supplier last year."

With eight right-hand corners, most of which are long and fast, and only five left-handers, most of which are much slower, the circuit works the right and left shoulders of the tyres very differently.

To face this challenge, and the high track temperatures expected, Bridgestone will bring its hard and extra hard compound rear slicks this weekend - but in both rear options the left shoulder of the tyre will be made of Bridgestone's soft compound.

By combining a hard or extra hard right shoulder with a soft compound left shoulder, the asymmetric rear slicks should provide a consistent level of grip and feeling throughout the lap.

"We will bring asymmetric rear tyres for the first time this season as having dual compounds to suit the right and left hand corners is essential for good feeling and performance at this circuit," stated Motorcycle Race Tyre manager Tohru Ubukata. "Because the left shoulders are not used as hard, the temperature in them is cooler than in the right shoulders but the soft compound on the left side allows the tyres to give optimal grip and rider feeling in these conditions."

But dual compounds won't be the only tyre change at Catalunya: Revised 2009 tyre regulations come into effect from the finish of the grand prix, when every rider will need to inform Bridgestone of how many of each compound of front slick they wish to use at the next round (Assen).

This change means that rather than every rider being given four of the harder and four of the softer compound Bridgestone front slicks, each can now choose whether they want four of each compound or five of one and three of the other.