New pit straight surface made Monza trickier in wet

Qualifying for the Italian Grand Prix was delayed for over two hours after it was red-flagged when Romain Grosjean lost control of his Haas on the straight.

Pirelli assesses each venue by measuring the macro roughness of the surface, and its engineers calculated at the start of the weekend that pit straight is now half as rough as the rest of the Italian GP venue.

"That's the worst place," said Daniel Ricciardo of the straight during the rain delay. "Around the chicane it's super wet as well, but that's low enough speed, it's no longer deemed dangerous. It's really towards the end of the straight, where the pit exit kind of starts."

"They resurfaced from the exit of the Parabolica to the first chicane," said Pirelli F1 boss Mario Isola.

"The roughness is quite different compared to the older tarmac. It's much smoother. If the roughness of the old tarmac is at 120 percent in the measurement we give to the teams, the new one is 60 percent, so it's half of the macro roughness.

"We wanted to check the level of grip, because obviously when you have such a big change in roughness you can have this part of the surface that is a lot more slippery compared to the rest of the circuit."

Although the straight was clearly challenging in the wet, Pirelli is not expecting any particular issues with wheelspin at the start on Sunday, when conditions are expected to be dry.

"If the level of grip is good, we shouldn't expect any issue with the start. The worry was with this new tarmac it would be slippery and difficult to start. Also the pitlane has the same tarmac. But looking at what we collected in terms of information, the grip is good."

Pirelli has found it harder to assess a representative track temperature, because of the different surfaces.

"The new tarmac is very black so to measure the track temperature we asked the guys to find a place that is representative of the rest of the circuit, because most of the circuit has a different tarmac with a different colour and a different heating process. If we measure on the very black one, we take the risk to have a measurement that is not fully representative, and is much hotter.

"This means under braking at the first chicane at that specific part the tarmac will be hotter than the rest of the circuit.

"But you arrive from a long straight, you cool down the tyre, and I don't think it's going to affect the tyre behaviour or performance."