Following criticism in 2016, F1’s tyre supplier agreed to drop tyre pressures for this year, to the collective relief of the teams and drivers.
But in Spain, the pressures were put back up by 2 PSI.
Pirelli’s Mario Isola explained: “We got the new downforce data from the teams three weeks before the race and the numbers were massively higher than before.
“We have simply reacted to that,” he told Germany’s Auto Motor und Sport.
However, Isola said the starting pressures in Barcelona could be seen as precautionary.
“After the first day, we will look at the situation again. When everything is in the safe zone, we will go back down with the pressures,” he said.
Indeed, it is believed teams can now run the usual lower pressures from Saturday practice.