Qualifying in the top 10 for the Chinese Grand Prix will be a delicately poised affair after Friday free practice confirmed Pirelli’s ultrasoft compound will serve at best as a one-shot qualifying tyre at the Shanghai International Circuit.
Pirelli has taken the unusual step of bringing the medium, soft and ultrasoft compounds to China, electing to skip the supersoft because it was deemed too similar in performance to the soft.
This season’s race will be the first in China to feature the ultrasoft rubber, and testing data from Friday showed it to be a poor race tyre at the cold-weather circuit.
Most drivers struggled to get more than 10 laps at reasonable pace from compound, with Carlos Sainz even telling his team that the ‘cliff’ — a level of wear beyond which performance drops off substantially — had returned to the tyres, making them virtually undriveable.
More intriguing still is that some drivers found it difficult to coax the purple-striped tyre around the circuit for an entire lap before it started losing performance, with Red Bull Racing’s Daniel Ricciardo particularly struggling.
“The ultrasoft is difficult,” he said. “For me I just struggled to get more grip out of the tyre today. I felt like after the first sector already I killed the tyre and the lap time didn’t really improve after the first three or four corners.
“We need to get that tyre working better over one lap. The long runs were better, but it’s still tricky.”
There were signs on track that the tyres were struggling towards the of a qualifying simulation run, with Lewis Hamilton’s fastest lap particularly ragged in the last sector. The Briton set purple times at the first two intermediates, but he failed to improve on his own time in the final third of the lap.
Haas’s Romain Grosjean, who was 19th on the time sheet after spinning his car on his qualifying simulation run, said the ultrasoft is effectively a qualifying tyre.
“I think [five laps is] very generous,” he said. “It’s about a lap.”
Using the tyre for ultimate one-lap pace is all well and good — indeed all teams’ tyre allocations are dominated by the ultrasoft compound — but starting the race on such a brittle tyre could prove a massive strategic disadvantage in the race.
With drivers who qualify for the top 10 forced to start the race with the compound on which they set their fastest time in Q2, teams will have to decide whether to boost their chances of making it to Q3 with the grippier tyre or risk using a tyre that is two stops harder to benefit their race strategy.
Ricciardo seemed to back the idea of risking the soft tyre in Q2.
“I think t’s no secret that I think a few people are thinking of qualifying on the soft,” he said. “It’s not that bad a tyre around here. The ultra doesn’t seem to last that long, so you might see a few yellow tyres in Q2.”
But for Red Bull Racing the risk is less severe, with the car’s pace advantage over the midfield likely to see it through to Q3 either way. In the closely matched midfield, however, tyre choice could mean the difference between starting in the top 10 or qualifying 15th.
Grosjean, however, said that might not be such a large price to pay to avoid the ultrasoft tyre.
“It could be one of those races where you prefer to be 11th rather than ninth or 10th,” he said.
“I think it’s the same thing. The big teams … can probably go through on softs in Q2 and that’s probably the best strategy. For us it would be a bit more of a challenge, because McLaren, Renault, Toro Rosso, Force India are in a tight battle.
“You need to get everything right to get into Q3. What we’ll see tomorrow will be interesting, and the race strategy will be pretty fun.”