Valentino Rossi warned that Ducati seemed to be losing ground again at Le Mans following a difficult Friday practice ahead of the French Grand Prix.
The Italian legend felt his struggling team was starting to move in the right direction after he finished seventh at the last MotoGP round in Portugal, but he was only ninth quickest at Le Mans on Friday, admitting that Ducati was having particular issues on worn tires.
"This afternoon we tried some bike settings that were quite varied, and we're trying to understand what the right direction is for finding more grip on corner exits," said Rossi. "So far, particularly when the tire starts to wear, we're losing a lot compared to the others.
"Our gap to the front is pretty large, and although the gaps in our group are quite small, there's more time between us and seventh place than there was in Portugal. We'll have to try to do better. We're trying some different things and we're working hard, so we'll see how we do tomorrow."
Rossi's teammate Nicky Hayden was one place further back and experiencing similar problems.
"I struggled a little bit everywhere," said the American. "Grip on the edge wasn't very good, and any time I would get going OK, I would have a hard time stopping the bike and would run wide on entry.
"I haven't had that problem much this year, and when you push wide, it also hurts the exit. We tried a couple of things but never really found a really good direction.
"We tried the hard tire a little this afternoon just to check, because the soft tire definitely feels like it's going off a bit, but I wasn't able to make it work that well. We'll sit down tonight and have a good think about it and see what to do tomorrow."