Petronas Yamaha's Franco Morbidelli, the convincing winner at Aragon a week ago, had to ride in safety mode for an 11th-place finish at Valencia as his front-tyre pressure went through the roof.

Morbidelli said it is a problem that occurs when riding in a group when no cooler air is reaching the rubber but can't tell whether it is an issue peculiar to Yamaha.

“It was a difficult GP for us, very difficult, I was struggling a lot because, when we are riding in a group, there is this problem we have where the front pressure goes sky high and the front gets really, really difficult to ride and really, really difficult to manage and you just have to go into safety mode and bring the bike home in the safest way possible,” said Morbidelli, speaking at the track.

“I don’t know, physics and science the same for everybod. So, I suppose with the temperature also other bikes suffer from this air expansion in the tyre. But I don’t know how much how it affects other bikes and I don’t know how much it expands in their tyres.

“I’m happy I was able to get the bike to the finish line with some points. The championship chances are almost gone, we are much further from Joan, who looks definitely to deserve this championship more than anyone else. But the gap between me and the second got smaller, so we’re still in play for that.”

Morbidelli was the only rider to choose hard Michelins all round. The factory Yamaha riders chose mediums all round as did Morbidelli's team-mate Fabio Quartararo.