Britain's Scott Redding says he is forced to take risks to find some sort of laptime on the Aprilia at MotoGP Sepang and chattering caused him to crash in the second free practice today.

Redding, who departs the team for BSB at the end of the season, lost the front at turn five and ended up in 20th place.

"Today we had big grip problems. In braking I am able to limit the damage, but then I am lacking grip and the bike moves around a lot. I am struggling with chattering, which cause me to crash," said Redding.

"We need to improve. I am forced to take risks to take advantage of the new tyre, but that isn't possible for the race."