The saga of Pirelli’s increased minimum tyre pressure requirements took another twist this morning when the Italian company warned teams that they cannot allow the pressures to drop below the prescribed minimum limit after cars leave the pits.
The minimum tyre pressures are measured by the car’s telemetry as they leave the pitlane, and that information is recorded by the Pirelli engineers who work with each team. Any anomalies are then picked up by the FIA.
There is clearly a suspicion that teams have found ways to meet the legal requirement as the car leaves the pits, but then run on track with slightly lower and thus more favourable pressures, which in turn aid car performance.
Pirelli says that if that is found to be the case the team concerned will be given higher minimum starting pressure figures.
In the letter Pirelli’s Mario Isola told the teams: “Our prescriptions about minimum starting pressures are based on the assumption that running pressures are higher than starting ones. These are the historical values we’ve seen, and we therefore need you to respect this in order to operate the tyres safely.
“If we find, during any session, that your stabilised pressures are equal to or lower than the starting pressures, we will give higher starting pressures limit to your Team, as agreed with FIA.”
One way to promote a pressure drop on track is to have very high blanket temperatures, and Pirelli has underlined that the temperature numbers are being watched: “I also remind you to respect the maximum temperature for blankets as we will ask FIA to random check the values.”
Teams are also believed to be trying to get around the pressure requirements via both set-up and operational means. It’s been suggested for example that drivers have been leaving the pits with new tyres and passing the minimum pressure requirement. They have then returned to the pits and the mechanics have reduced the pressures before the car heads out again to do a proper run.
“We need to be sure that the running pressure is in-line with the starting pressure,” Isola told this writer. “I fully understand that the teams need to find performance, that is clear. On the other side we have to be sure that the tyres are working in the right way. It’s always a balance between the two.
“When we find something that is not what we want, the tyre is not operating in the range we want we need to be sure to come back to a situation is under control.
“For me it is not correct to say that people are cheating. They are trying to find the room in the regulations to do something that is allowed because it is not forbidden. If we realised that this new idea has a negative impact on the tyre, we need to react, and to police it. They’ve found some grey areas where they can work at the limit, that’s all.”
Meanwhile one team insider told this writer that pressures could drop dramatically during the course of Sunday’s race: “The car set-up can promote a reduction in pressure, but the biggest factor is tyre wear. As the rubber thickness reduces the tread temperature decreases and this cools the air inside, and pulls the tyre pressure down. This is what happens during a long stint e.g. Ferrari in Spa. And it’s what’s going to happen tomorrow when everyone attempts a one-stop strategy.”
Adam Cooper's F1 Blog 
Drivers criticise Pirelli for putting them at risk and then teams/engineers do this, it’s disgraceful. The drivers will know about it too, they will have been briefed about how the tyres are being prepared & managed. If they play games like this they will end up boxed in with ever tighter regulations and they will only have themselves to blame.
If Pirelli made proper tyres, they wouldn’t have to prescribe such narrow operating conditions … and teams could actually use the brainpower they’re paying the worlds best engineers to their advantage.
Making the teams responsible for their poor tyre design and construction, and then still having the arrogance to threaten teams and the organisers is just typical of Pirelli’s over-inflated opinion of their worth.
It’s bout time Hembery gets away from trying to be a celebrity in front of the media and F1 world, and starts running a company that supplies non-exploding tyres.
I’m really on the fence with this issue as I can see both sides of the discussion.
I’m sure Pirelli could provide a bulletproof tire, but what impact would it have on performance? And with all the criticism Pirelli is receiving you can’t blame them for closely monitoring the operational windows they establish.
Personally I would prefer it if the teams had latitude to do whatever they want with the tires, BUT accept all the risk and responsibility if things go upside down. Don’t whine after the fact. It’s racing, shit happens.
You will often find that, in multiple forms of motorsport, teams will rarely want to take responsibility for their actions and will shift the blame to anybody else. Who wants to admit that they’ve made a mistake?
I recall one tyre engineer from the US racing scene noting that they were being given serious abuse in the press by a team for problems with the tyres. Even though everybody within the sport knew the reason was because the team was running the tyres about 30% below the minimum recommended inflation pressure and with 2 degrees more camber than recommended, the team in question was able to obscure that fact by kicking up a massive fuss in the press and was able to blame the tyre supplier.
What a joke. Too bad Bernie is going to keep Pirelli around for years to come
This is a sad, sad joke.
Now we have a tyre company running F1. Bloody ridiculous and directly caused by Bernie’s money grubbing ways.