New Michelin MotoGP front tyre causing problems - Jorge Lorenzo

Several riders crashed on the first day of testing at Valencia, including the day's pacesetter Marc Marquez, as the field got used to new tyres and electronics for 2016.

Lorenzo described Michelin's rear tyre as "fantastic" but he said the front was the likely cause of most of the crashes.

"I now have the feeling that I think everybody has," the world champion said at the end of the first day.

"At the entry of the corner we lose a bit of stability and also when reaching the maximum lean with throttle the front can close [lose grip] suddenly if you push too much.

"It's the opposite for the rear tyre - it's fantastic. It's unbelievably grippy and gives you a very good feeling.

"We need to work a bit more on the front. We didn't solve the problem completely."

Lorenzo's team-mate and 2015 title rival Valentino Rossi added the switch to Michelin has a lot of knock-on effects on other areas of the bike.

"It's a big change and it will be interesting," Rossi said. "The tyre will make a big difference for next year.

"A lot changed, especially the setting, the weight distribution of the bike and everything.

"It looks like our competitors are a little ahead, because they've made more kilometres with the Michelin.

"The rear tyre has very good grip - the front is a big difference.

"We need to understand how much weight this tyre needs to turn at the maximum. We need some more time."

Ducati's Andrea Dovizioso said it will also be up to the riders to adapt their style to the Michelins, as well as changing bike set-ups.

"These testing days are very important because this time the change is a really big one," said Dovizioso.

"The Michelin tyres have very different characteristics and so we also have to adapt our riding style, because the corner approach and the lines cannot be the same as the ones we were used to.

"There is still a lot of work to do to adjust and understand the direction to take for the future, but it's important to start off well, and in any case first sensations are positive."