Pirelli has increased minimum rear tyre pressures for the remainder of the Azerbaijan GP weekend as stress levels in Baku have exceeded the manufacturer's expectations.
The boost from 19psi to 20psi is another variable that teams were forced to take into account at the start of Saturday's running.
For this year's return to Baku, Pirelli opted to supply a softer tyre selection relative to F1's last visit to Azerbaijan in 2019.
The C3, C4 and C5 choice was initially made to introduce an extra strategic element, bringing into play a hard tyre that wasn't used at in 2019.
"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."
Given the potential degradation level of the soft C5 tyre, teams could be encouraged to qualify for Q1 using the C4 medium compound. Regardless, Isola expects a ones-stop strategy to be the norm on race day.
"Looking at the numbers expected, I believe that we will still have a one-stop race with probably C3/C5, or C4/C5," said the Italian.
"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.
"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."
But Isola reckons that different track temperatures spread across the track could throw a spanner in the works for some drivers in Baku.
"So sometimes your have the main straight that is under the sun, and two-three kilometres in the back that are under the shadow," he said. "And the difference in temperature between the shadow and the sun can be 20 degrees. So it is something to consider."
Gallery: The beautiful wives and girlfriends of F1 drivers
Keep up to date with all the F1 news via Facebook and Twitter
