Repsol Honda riders Casey Stoner and Dani Pedrosa led one session each during free practice for the Spanish MotoGP at Jerez on Friday.

Stoner, winner on his RC212V debut at Qatar earlier this month, was quickest by just 0.028sec over the home star in the first 45-minute session, before Pedrosa turned the tables on the Australian ace by 0.188sec during the slower afternoon session.

Losail has always been a strong circuit for Stoner, but Jerez is among his least-successful (one podium from nine races) and the #27's Friday speed was an especially worrying sign for his 2011 title rivals.

"The first session went well and I had a good feeling with the bike, we tried to repeat this in the afternoon session but the conditions weren't perfect - it was quite windy," said Stoner.

"[The Honda] seems to be a little smoother to ride here than [the Ducati], but it's a shame the weather wasn't better so we could spend some time working on the settings.

"In general both bikes we tried seemed to work pretty well and we'll pick up from there tomorrow to concentrate on the set-up. The grip level doesn't seem to be so good here, I think everyone is struggling with this so that's another element we need to work on for qualifying."

Stoner, the 2007 world champion, and Pedrosa, the 2010 title runner-up, were the only riders to lap below 1min 40sec on Friday as they each beat the official race lap record of 1min 39.731sec set by Pedrosa on his way to second behind Lorenzo in a thrilling 2010 race.

"I think we are doing a good job," said Pedrosa. "The bike was working OK, it was moving a little but maybe because the grip was not so good today; other riders were also struggling with it and we saw some crashes in all the categories.

"Also the strong wind played a part in the afternoon, it was more difficult to control the bike especially on fast corners and we couldn't improve the lap times. Let's see if the track conditions improve tomorrow and if we can do better."

As on Friday, Stoner and Pedrosa had similarly dominated the Qatar weekend until a recurrence of Pedrosa's left arm/shoulder problems - for which he will seek surgery next week - dropped him to third in the race behind Yamaha's reigning world champion Jorge Lorenzo.

Just how badly the arm numbness will affect Pedrosa during Sunday's race remains a major concern.

"Regarding my physical condition, I'm struggling in the same way I did in the Qatar race because the situation has not changed, but I cannot do anything to feel better, so I'm just focused on riding as best as I can," said Dani.

"I'm doing short runs because it's better for me and working on the bike to prepare for the race. We hope to improve tomorrow and do a good qualifying practice".

Third Repsol Honda rider Andrea Dovizioso crashed at high speed at the end of morning practice, in which he was sixth, and only managed twelfth in the afternoon.

"It was a difficult day," confessed the Italian. "This morning I crashed on the very last lap because I lost the front, without any warning at Turn 11. The crash in itself was not too bad but then the wind in the afternoon made things worse.

"I think the second practice suffered due to these things put together and as a result I lost the feeling with the front. I couldn't ride as I am able to do and it's not a nice feeling but it's useless to complain, we have to continue working.