Pirelli pressure hike adds to Baku tyre challenge

Pirelli always reserves the right to make a change after Friday's running, and on this occasion it has upped the rear pressures from 19psi to 20psi.

The change is an extra curveball for teams who struggled to optimise tyre management on Friday, with graining proving an issue for some. Charles Leclerc and Valtteri Bottas were particularly vocal about tyre issues on team radio in FP2.

Teams have done their homework overnight in order to optimise their cars based in the data they had from Friday running, and the change has added an unexpected variable that they now have to adapt to.

Tyres are a particular challenge this weekend because in 2019 the Italian company brought its C2, C3 and C4 compounds to Baku, but for this year it has dropped the harder C2 and added the C5, the softest of the five compounds in its range.

"The severity that we measured on telemetry is higher than the simulation," Pirelli F1 boss Mario Isola told Motorsport.com. "So we had to react with a fine tuning of the pressure.

"Our system is not taking into account only the speed, it's the speed, the load, the camber, the corners, there are many parameters that are making the equation, so it's not just one.

"What we can see from the telemetry is that the teams are stressing the tyres more – we need the real data to judge the real stress on tyres, otherwise we have to rely only on the simulation."

Teams anticipate that it will be challenging to make the C5 last in the race. That will potentially put a premium on getting through Q2 on the medium C4, and thus using it for the start.

Pirelli expects a one-stop strategy to be the norm, mainly for reasons of traffic and track position.

"All the three compounds are one step softer," said Isola. "In reality in 2019 we selected the C2, C3 and C4, but nobody used the C2 during the race. So it was a one-stop strategy with C3 and C4, that are the hard and the medium this year. So I believe that with the C5, we just added a bit of strategic option to the race.

"Looking at the numbers expected, I believe that we will still have a one-stop race with probably C3/C5, or C4/C5.

"The choice makes sense, looking at the race two years ago. Honestly, if we look at the options on two stops, at the moment they are slower compared to one stop."

Isola says that the Baku track provides special challenges, especially with the long straight cooling down the tyres and making it easier to lock up and damage them at Turn One.

"It's a bit tricky, this circuit," he noted. "The most difficult part is to balance the front axle with the rear axle, most of the corners are 90 degrees. And you need a lot of traction from the rear. So you put energy into the rear.

"You have a long straight, with a cool down, especially of the front tyres, that is quite big. So front locking at the end of the straight, or keeping the front tyre in the right temperature, is the most important element for the set-up of the car.

"Adding a softer choice compared to last time is helping with the warm-up. But it's probably not helping in balancing the car. So they still have to work around that. And hopefully we have more action because of that.

"Obviously if we have a safety car, everything is different. And we know that. But in a normal situation, without safety car, without any interruption of the race, I believe that one-stop is basically the strategy.

"They don't lose a lot of time in the in the pit lane for the stop, we estimate 21 seconds. So it's not because of the pitlane loss, it's more because of traffic. It depends on the level of degradation and overheating."

Isola stressed that inconsistent track temperature over the lap also makes life difficult for drivers.

"We are in Baku one month earlier compared to two years ago. But the weather forecast is for warm temperature. So we are expecting up to 50 degrees of track temperature. But when you go in the old part of the circuit, you don't have all the track that is under the sun.

"So sometimes your have the main straight that is under the sun, and two-three kilometres in the back that are under the shadow. And the difference in temperature between the shadow and the sun can be 20 degrees. So it is something to consider."