Valtteri Bottas was the sole notable absentee from Free Practice 2 in Suzuka on Friday, the Finn not taking part in any of the afternoon's session.
Bottas had been disappointed with his morning pace which saw him finish with the tenth fastest time in seriously wet conditions, out of the 12 drivers who took part. His lap of 1:53.964s was four and a half seconds off the top FP1 time set by Carlos Sainz.
While some of that difference can be put down to the fluctuating conditions, and Sainz timing his run on intermediate tyres when the waterlogged track was marginally at its best, Bottas was also worried about the overall disappointing handling of the Williams in the wet.
"Understeer has been the problem, but I think we improved it slightly," he explained. "I think it's the cornering in general that's the main problem.
"We tried different things and when I went back with an old set of tyres I could improve my time with a different kind of set-up, so I think that was a step.
"The car is made for dry conditions. I can't say much more really, we obviously need to look at everything and learn more."
The understeer led to heavy graining on the front tyres, and with limited sets available Bottas was forced to sit out FP2 rather than eat up his remaining sets of wet and intermediate tyres in the same way.
"We did a couple of runs in practice 1, and in practice 2 the set that I had in practice 1 - the front tyres - were already in very bad condition," he said. "We wouldn't have learned anything by going out again, so [we ended up] just saving the tyres.
"We could have not really learned anything by doing any runs with new sets. In case there's any more rain we didn't want to use any more so it's a shame.
"All the sets we use in practice are the same sets we have for the whole weekend so it's quite tricky," he pointed out, adding that it was a shame that they couldn't afford to run any more laps in the wet given there was clearly much they needed to find out about the way the Williams car performed in such conditions.
"It's a shame because we have a lot to learn, a lot to improve in the wet, but we just couldn't run," he said. "We do have a lot to learn in the wet really and a lot to try but we didn't want to risk in case there's any more rain coming."
Kvyat edges Rosberg in FP2 at wet Suzuka
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