Pirelli hopes "responsible" teams won't take stint length risks
Pirelli Formula 1 boss Mario Isola is worried that teams will take risks with stint lengths in the 70th Anniversary GP – but he hopes that they will be “responsible” in the wake of last weekend’s failures.
Lewis Hamilton, Valtteri Bottas and Carlos Sainz all suffered front left failures in the closing laps of the British GP after pushing their C1 tyres for an unusually long stint, a result of an early safety car intervention.
For this weekend as a precaution Pirelli has upped the minimum front pressures by 2psi and the rears by 1psi.
In addition Pirelli believes that the move to a one-step softer range – with the C2, C3 and C4 now in play – will push teams toward two-stop strategies, automatically ensuring shorter stint lengths.
However it has not mandated any maximum stint lengths, and there remains a possibility that teams will try a one-stopper involving a long stint on one of the compounds.
Isola admits that Pirelli is relying on the teams not to push the limits of tyre life.
“Yes, I am worried because I don't want to see any tyre that fails on track,” he said when asked by Motorsport.com. “That is a priority. So we all need to pay attention.
“What we can do from our side is to give as much information as we can to the teams in order for them to run our product in a safe way. If they take a risk, they take risk, we cannot stop anybody, we cannot jump on track and stop a car, for sure.
“So I hope they will be responsible, knowing what happened last Sunday, not to do something above the limit.
"That is why we decided to avoid any mileage limitation. I trusted the teams, I trusted their ability and they are professional, and they know what to do."
As the C1 that failed in the British GP is not in use the hardest compound is thus the C2. Pirelli learned useful lessons about it when Haas driver Romain Grosjean ran it for 36 laps last weekend.
“What happened with Grosjean last weekend is clear,” said Isola. “The tyres were completely finished. And that is not a mystery, 36 laps on the C2 compound are too many. And if you consider that a one stop-strategy means that you have to run at least 30 laps on the C2 and 20 plus on the C3, it is something that we are going to exclude for Sunday.
“If you run a tyre that is completely worn, you expose the construction, and in that case you take a lot more risk because the construction is not protected by the tread.
“So you hit debris, you hit the kerb, you hit anything and you take the risk to damage the construction. If you damage the construction, in a high severity circuit like Silverstone, it is very easy that you have a loss of air, and then a deflation, and you have to stop the car.
“That is something that is really evident to everybody. So I hope they would make a plan taking that into consideration.”
Isola says it is impossible to impose a limit on how far a given compound can run.
“The reason why we decided not to impose any mileage limitation to the teams is that each car is different each, driver is different. And one of the important things in F1 now for the show is the possibility for the teams to plan different strategies.
“If we were ever to suggest or define a limitation in the number of laps for each compound it means that we bring all the teams to plan the same strategy, that is not in the target for the show. So what we did is to give clear information to the teams through our engineers in order to make them aware of our findings, the result of the analysis and useful information to make their plan for this weekend.
“I believe that a two-stop strategy will be the baseline for this weekend, but each one can decide if they want to use a mix of hard, medium or soft, or maybe move even to a three-stop strategy.
"Three-stop on paper is not the quickest solution, but we can see a good number of permutations on the two-stop using all the three compounds and that is probably good for the show this weekend."
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