Jorge Lorenzo was quickest on the opening day of MotoGP's tire test at Phillip Island on Monday.
The test has been arranged to avert a repeat of the problems that blighted last year's Australian Grand Prix, when tire wear issues forced MotoGP to add mid-race pit stops and truncated the Moto2 event.
Bridgestone has brought six new varieties of tires to the test, which is being attended by the factory Yamaha, Honda and Ducati teams. The squads are sitting out the previously scheduled Qatar test later this week to ensure they do not get an unfair advantage.
Lorenzo had been extremely unhappy with Bridgestone's 2014 tires during last week's Sepang test, but was quickest for the majority of day one at Phillip Island.
Cal Crutchlow took second for Ducati, now running to Open class regulations, 0.363sec down on Lorenzo. The second Yamaha of Valentino Rossi completed the top three ahead of sole Honda rider Dani Pedrosa.
Crutchlow's teammate Andrea Dovizioso had limited running due to illness and was fifth.
Leading Moto2 teams Marc VDS and Aspar are also present to carry out development work for Dunlop as it had the same issues as Bridgestone at the track in 2013.
Tito Rabat was fastest among the feeder series group. His Marc VDS teammate Mika Kallio had a big accident at Siberia, but was passed fit to resume testing on Tuesday after precautionary wrist scans.
Pos Rider Team/Bike Time Gap Laps 1. Jorge Lorenzo Yamaha 1m29.213s 68 2. Cal Crutchlow Ducati 1m29.576s +0.363s 68 3. Valentino Rossi Yamaha 1m29.730s +0.517s 85 4. Dani Pedrosa Honda 1m29.961s +0.748s 88 5. Andrea Dovizioso Ducati 1m29.965s +0.752s 60 6. Tito Rabat Marc VDS Kalex 1m32.316s +3.103s 100* 7. Nico Terol Aspar Suter 1m33.290s +4.077s 82* 8. Mika Kallio Marc VDS Kalex 1m33.440s +4.227s 62* 9. Jordi Torres Aspar Suter 1m34.000s +4.787s 56* * Moto2