Malaysia's capricious weather has left some teasing questions after the first day of practice at Sepang. Red Bull's drivers are complaining about how the whole competitive picture is being dominated by tyre durability - but Lotus is not.
On one-lap pace there looks little to choose between the two cars, but in the dry first practice the Red Bulls - and others - were shredding the hard-compound prime tyre. Kimi Raikkonen's Lotus was not.
The afternoon running was interrupted by a rain shower at just the part of the session that the option-tyre long runs usually commence. It's quite possible that the 'greenness' of the morning track contributed a lot to the heavy wear seen on some cars and that it may not prove quite the drama that the Red Bull guys were concerned about.
Certainly, Mercedes - absolutely determined to get as much long-running in as possible after its difficulties in the second stint in Australia - did long runs with both Lewis Hamilton and Nico Rosberg that showed very controlled degradation after as many as 15 laps, but this was on the hard tyre.
Red Bull was not happy with the tyres © LAT
Pirelli reckons stints in the 'early' 20 laps will be feasible on the hard and up to 15 laps on the medium. This would make the race a theoretical three-stopper, just as it was in Melbourne for most - but not for Raikkonen's Lotus, which won by being able to go quickly with just two stops.
The key to whether the Finn can repeat his Australian feat will be if the Lotus is as easy on the tyres at this wear-limited track as it was in Melbourne on a graining-limited circuit - and from the data of Sepang practice we cannot know that.
He was unable to complete a long run in the morning because of a KERS problem and the rain prevented an answer in the afternoon. We do not have any clues from the other Lotus of Romain Grosjean either, as he continued to suffer from an elusive chassis problem that left him both off the pace and wearing the tyres.
"No matter what we do with the set-up it feels exactly the same - which was what happened in Melbourne too," said the Frenchman. "There it was understeer, here it is oversteer but the problem is essentially the same. The team is working very hard to trace the problem but as things are I cannot compete at the front."
In terms of one-lap pace there was just a tenth of a second separating Lotus and Red Bull in both sessions - though the world champion cars do tend to run a little heavier, so that may not be totally representative and it could be that its Melbourne qualifying advantage is intact.
Ferrari appears to be solidly quick in all conditions - if never the outright fastest, just as in Melbourne. Felipe Massa again appears closely matched to Fernando Alonso.
Because Mercedes skewed its Friday running in a very different direction to the other three top teams it's not clear exactly clear where it stands on one-lap pace, but Ross Brawn is hopeful that the consistency is now there.
Mercedes's form is not yet clear © LAT
McLaren is beginning to get a handle on understanding the aerodynamic problem afflicting the MP4-28, but for here all that can be done is a band-aid solution, keeping the car in a more limited ride-height range to limit the underbody stall that afflicts it when running low.
In the mixed conditions, Jenson Button's talents remained very much on show - as he was consistently among the very quickest as the rain arrived. In the dry it looks again as if the McLaren drivers will be fighting out Q3 qualification with the Force India and Sauber drivers.