Monday's session was held in hot and sunny conditions with Casey Stoner resuming where he left off on Sunday, topping the timesheets with a best lap time of 1min 32.464sec using the new Ducati GP9 machine.
Tuesday's session was curtailed by intermittent rain and only seven riders emerged during the final two hours to try Bridgestone's wet weather tyres.
"I am really very satisfied with the first trials of our new specification slick tyres which we were able to carry out in the dry conditions on Monday," said Tohru Ubukata, Bridgestone Motorsport's manager of Race Tyre Development. "Considering it is the first time that we are producing MotoGP tyres for everybody in a sole tyre supply situation, I think we have made a good start.
"We have used the foundation of our 2008 tyres for these new specs but made some important alterations to ensure that the tyres have a wide operating window and can work well for all teams and riders. We have reduced the overall grip level of the tyres in order to accomplish this and the feedback from the riders has been encouraging.
"The track conditions on Monday were excellent and the lap times were also very competitive as a result. The most important thing for us is to know that our tyres are durable because this will be one of the most fundamental things for us next season. Some riders put up to 40 laps on the same set of tyres with great consistency which was particularly impressive.
"Unfortunately the conditions today have not been as good, but the information obtained from yesterday's session will be instrumental for us to hone the tyre specs over the winter period.
"This new situation as the only tyre manufacturer will be a new challenge for us, but I am sure we are up to the job and can live up to the trust that the teams, manufacturers and riders have shown in us and our capabilities.”
Bridgestone will now use the data collated at Valencia in order to prepare tyres for the next test session, which will take place at the end of November in Jerez.