After assessing data from Friday MotoGP practice at the resurfaced Phillip Island circuit, exclusive tyre supplier Bridgestone has specified that all riders use the harder rear option for Sunday's Australian race.

The resurfacing has been praised by the riders, but changed the tyre wear characteristics.

Shinji Aoki, Manager of Bridgestone Motorsport's Tyre Development Department, explained:

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"Our analysis shows that the tarmac has made this track tougher on tyres, so we have decided that - although riders can still use the softer rear slicks for the remaining practice sessions and qualifying - for the race we have specified that all riders use the harder rear slick options available to them."

The harder tyre option has rarely been the favoured choice this season.

Some Moto2 riders are also thought to have tyre endurance concerns with their Dunlop rubber.

UPDATE 1: A extra hard rear tyre compound was offered in FP4.

UPDATE 2: The Grand Prix Commission announces new rules regarding tyre use and length of race changes:

"Sporting Regulations - Effective Immediately
Currently the Race Direction is the only body competent to change the length of a race. This competence has been extended to authorise Race Direction to be able to change the length of a race outside of the minimum and maximum lengths defined elsewhere in the regulations.

"Technical Regulations - Effective Immediately
There have been recent situations where teams and riders have ignored the recommendations of the official tyre suppliers on issues such as tyre pressures. It is suspected that this has led to cases of abnormal degradation of tyres affecting the safety of the riders.

"A new regulation has been approved which will compel teams and riders to use the tyres according to the parameters agreed by the Technical Director and the organisers in consultation with the official tyre suppliers."