Jorge Lorenzo was a frustrated figure after losing confidence in his Bridgestone tyres at the Sepang II MotoGP test.

Lorenzo was fifth fastest on the first day of the official three-day test in Malaysia, with his best lap of 2m 01.158s leaving him 0.310s behind Gresini Honda pacesetter Alvaro Bautista.

The Yamaha Factory Racing rider tried a number of set-up changes to improve his grip problems without success.

"The new rear tyres, both the soft and the hard, are not working properly on our M1. For the moment we are finding a solution for the tyre; it seems for Yamaha that it is much worse," said Lorenzo.

"We are trying everything on the bike - all the set-ups that we can - but when we go on to the track it's always the same feeling.

"We also had problems with the electronics. We are trying to do the seamless downshift in the braking like Honda, but for now none of it is working.

"We are trying to work with Bridgestone to make them change the tyre but for the moment they have a very closed mind about that and they don't want to change.

"They say this tyre is the safest, but we say the opposite - that it is more dangerous," added Lorenzo.

"It seems Bridgestone will not be providing different tyres this year so we have to adapt to the situation."

In response to a suggestion that Lorenzo may have to adapt his riding style this year to suit the 2014 Bridgestones, the Mallorcan responded: "When you're not happy you can make gymnastics on the bike but the thing will be the same.

"The tyres don't give me any confidence in the corner entry, in the middle of the corner and on acceleration."