Stoner unsure which bike to race

The Ducati rider was third and fourth in Friday's two free practice sessions, but made major changes after struggling in today's final practice, where he only managed the ninth quickest time.

"This morning we were struggling with a few set-up problems, we seemed to go backward with the turning and the grip," Stoner said.

"So we looked over everything, saw what we needed and came up with a good package before the afternoon session.

"We hadn't been able to find a good feeling with the second bike, so we swapped the forks out of the first bike and that seemed to solve the problem.

"Straight away I felt comfortable. We made a couple more changes during the session and our race pace is looking very good.

"I'm not sure if the problem was in my head or in the forks! I don't know which bike we'll race, both have performed pretty well."

Stoner believes that the set-up changes also helped his Ducati to work more harmoniously with Bridgestone's qualifying tyres after difficulties earlier in the weekend.

"We have struggled a bit to get the rear tyre to work at a hundred percent and we have experienced some spinning, but this afternoon we have found an almost perfect setting to get the bike and Bridgestone tyres to work well," he said.