Factory Ducati star Casey Stoner has confirmed that, like Alice's Toni Elias, he is struggling to find a rear tyre that suits the Desmosedici at Sepang.
Sepang is the second event in a row at which Elias has battled rear tyres that are too hard for his weight and riding style, a problem Stoner explained is also partly due to the characteristics of the Desmosedici.
"It has been a frustrating day to be honest because we don't seem to have a tyre that works at this track and suits our bike," said Stoner, winner of his home Australian Grand Prix last time out.
"The Desmosedici puts less pressure on the rear than other bikes so we tend to run softer rear tyres, but this circuit requires a hard compound and it seems the tyre that works best here is giving us a bit too much rebound. The bike is moving around a lot and I'm getting a lot of vibration," he explained.
"The limited track time this afternoon leaves us with a lot of work to do tomorrow so hopefully the weather stays dry. We had similar issues in Phillip Island and we managed to get on top of them so I think by Sunday we can have a good solution."
Typically, such tyre problems didn't slow Stoner down much and he was still third fastest in both sessions, concluding the opening day 0.303sec behind Tech 3 Yamaha's Colin Edwards.
Meanwhile, team-mate Marco Melandri was left one place in front of Elias, in 14th.
"We worked hard with the tyres today but the conditions were constantly changing so we couldn't find anything we felt happy with," said the Italian. "We also have to work a lot on the bike because when I'm not pushing it feels okay but as soon as I try to pick the pace up the same old problems return. We always have problems opening the throttle and with front feeling. If I ride at a normal pace it's fine but the harder I push the slower I go."