Pirelli lowers tyre pressures as load fears prove unfounded

In pre-season testing, Pirelli ran with the rear tyres at 18psi, but that was raised to 20psi for the start of the Spanish GP weekend on the basis that car development over the past two months had substantially increased downforce loadings, based on estimates provided by the teams.

However, having studied the data collected on Friday, Pirelli has decided that it can now safely lower the minimum level to 18.5psi. The fronts have dropped from 22.5 to 22.0psi.

"What we received two weeks ago in terms of simulations was saying that the teams were expecting a much higher load on the rear tyre compared to the pre-season test," said F1 technical boss Mario Isola before the decision was confirmed.

"In the pre-season test we had 18psi of starting pressure for the rear tyre, and here now we have 20psi.

"These 2psi are because in the simulation we see a much higher load on the rear tyre. If this is not confirmed because the simulations are overestimating the rear loads, we'll lower the rear pressures."

Regarding how the figures are arrived at, he said: "The 2psi are not just a direct correlation between the old pressure. You have to take into consideration the camber.

"Basically they analyse a full lap, including the speed, the camber, and not only the loaded tyre – sometimes the unloaded tyre is working with a lot of vertical load at high speed, with much higher camber.

"Sometimes it's not the loaded tyre that is in the most critical situation. They make an analysis of the whole lap, and race distance and so on, and then they came up with the prescription."