Stoner not worried by tyre problems

The championship leader fell to fifth at the Sachsenring last weekend as he struggled for grip, and was reeled in and beaten by title rival Valentino Rossi at Assen a fortnight earlier.

Stoner had dominated practice and qualifying in Germany, but could not sustain that speed in the extremely hot conditions on Sunday afternoon.

"I'm not worried and I don't think Bridgestone needs to make radical changes for the very hot races like Sachsenring," Stoner told Gazzetta dello Sport.

"I'm leading the championship and the tyres have always been competitive. There's no point getting worried if for once we had some problems."

Bridgestone's motorcycle tyre manager Hiroshi Yamada said the Japanese manufacturer was disappointed by its race form, but had anticipated problems at the Sachsenring.

"After practice we had expected a different result, but even before that we knew the German track would have been one of the toughest for us, together with Laguna Seca and Portugal," he told Gazzetta.

"We are sorry about the problems suffered by Stoner, (Marco) Melandri and (John) Hopkins.

"It was the temperature, higher than on Saturday, and the new asphalt, very abrasive. We didn't know about the resurfacing of the track so we couldn't bring the optimal solution.

"The problem is that with so much heat and such abrasion, after a while the left shoulder of the rear tyre started to fail until it suffered a sudden drop.

"We are not worried: Michelin has done a good job but we won't be fiddling our thumbs."

Yamada said he was also optimistic about Laguna, despite Bridgestone's previous problems at the California track, and the fact that it too has been resurfaced.

"At Laguna they've also resurfaced the track, but I think we'll be ready there: I'm sure we'll be able to be main players again," he said.

Stoner agreed that Bridgestone's 2006 Laguna difficulties did not mean it would struggle again this season.

"We've already seen this year that the situation is different compared to last season, so you can't make comparisons," he said.

"Besides, in 2006 everyone had tyre problems not so much for the heat but for the asphalt. But it should be different now, as it's been resurfaced."