Lack of dry running makes Ross Brawn unsure Schumacher can take a podium in German Grand Prix

Schumacher was fourth fastest in qualifying, but moves up a place thanks to Mark Webber's gearbox change.

Brawn was happy with the performance of the car in dry conditions, but believes that it will not become clear until the the early stages of the race how strong Schumacher is able to be.

"The car wasn't too bad in the dry, but none of us have had much running [in such conditions]," said Brawn when asked about Schumacher's prospects.

"We did our high fuel running on Saturday morning and in the dry period we had and made a few changes after that which we didn't get too much of an opportunity to try in qualifying, so we will have to see.

"It will again be a race of managing the tyres. We expect it to be much warmer and that can bring a different perspective on things."

Brawn is uncertain of how well Mercedes will be able to manage the tyres tomorrow, with track temperatures expected to be significantly higher.

"His [Schumacher's] struggle on the tyre in Q1 was about getting temperature into it," said Schumacher. "Hopefully that's not a problem for tomorrow.

"With this tyre, the balance is [between] not getting it too hot and not getting it too cold so we do not get it working correctly. Michael's problem was not getting it working properly."

Brawn added that he is hopeful that the car will be more consistently on-the-pace than it was at Silverstone, when Schumacher was able to lap more strongly in the final stint relative to the pace than he had been at other times.

But the different conditions on Sunday afternoon will throw a curveball into the mix.

"We haven't experienced in practice what we will in the race, so trying to anticipate what you need for the race is tricky," he said.

"We have been focusing for some time now on trying to widen the tolerance of the car to bring a better range of balance so that when these conditions change, we don't get caught out.

"This will be another test of how we have improved. Everything that we can do in terms of tyre pressures and other admissible changes will be done to try and take care of the extra temperature that we will see in the race."