The degradation of the Pirelli tyres in searing Sepang temperatures was the talk of the paddock ahead of the Malaysian Grand Prix, with Red Bull and McLaren predicting a forced three-stop race strategy tomorrow.
The tyres, which lasted longer than expected on their debut at the season-opening race in Australia a fortnight ago, have suffered in the stifling Malaysian heat where track temperatures reached 49 degrees yesterday with 50 per cent humidity. The tyre wear meant drivers were forced to take a more conservative approach than last year during practice ahead of the 56-lap race.
Mark Webber walloped everyone by 1.6sec in the morning session, but though he stayed fastest for Red Bull in the afternoon, Jenson Button was only 0.005sec adrift and Hamilton in the other McLaren was just another tenth of a second away.
"Obviously tyres don't last as long [as in Melbourne], that's for sure, but I think this is the same for everyone," world champion Sebastian Vettel said after finishing fourth in the second session.
"It is difficult to give a number [of laps the tyres will last for] but I don't think you will two-stop, and one-stop is... forbidden," the championship leader joked after a long pause to choose a suitable final word.
Vettel's Red Bull team-mate Webber offered a similarly dim view of the tyre's longevity. "More than five, less than 25," the quick-talking Australian replied when asked how many laps he thought the tyres would last in Sunday's race.
McLaren's Jenson Button, a winner here for Brawn in the a weather-truncated race in 2009, said: "It's very difficult around here, the tyres are doing what we expected... but it is very different to what we saw in Melbourne.
"This afternoon's session was much better than this morning's," he added. "We found things a little difficult during P1; after Melbourne, we chose to head in a certain direction in order to resolve the issues we had in the first race, but the track is very different here. So we went back on a few of those changes, and everything is performing better now.
"We don't know what fuel loads the other teams were running, of course. What's important, though, is that we changed a lot of things on the car and they were all positive steps. We feel like we've found a good direction."
Pirelli's motorsport director Paul Hembery faced a number of questions about the tyres after the day's action and said the conditions had been very testing. "We do have more degradation here than at Melbourne and there's quite a bit of difference in times between the soft and hard tyres, so the teams must be working out their strategies now based on that," he said.
"I'm guessing on a three-stop strategy but we were surprised by the one-stop Sauber managed in Melbourne, which we did not envisage. But three looks like being the strategy here and that is the expected scenario."