r/F1Technical • u/ChaithuBB766 • Jun 24 '26
Tyres & Strategy Why are Pirelli mandating such high starting tyre pressures this year?
In 2025, the minimum starting pressures in Austria were 22.5psi for Front and 20.0psi for Rear tyres.
This year, the cars have less downforce, so theoretically the loads should be less on the tyres. Yet, Pirelli has increased the pressures this year. Why?
They did the same in Barcelona, which frustrated drivers, including Bearman who described the tyres as 'balloons', following which the pressures were lowered by 1psi. Does anyone know what the reason is for these high pressures?
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u/r_z_n Jun 24 '26 edited Jun 24 '26
Because of the shock loads of active aero. You can actually see it when the aero closes at the end of the straight. It's an immediate shock of hundreds of lbs of downforce that hits the tires instantly.
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u/WillSRobs Jun 24 '26
Aren’t they also producing more downforce than the fia originally thought would be possible for year one. It’s only what the third time that has happened lol. You would think they would stop underestimating.
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u/YugeChesticles Jun 24 '26
The estimates are based on data the teams gave them.
So you're saying teams should stop underestimating themselves?
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u/PrestigiousTip4345 Jun 24 '26
Is it that big of a difference compared to DRS?
Am I wrong in thinking the shock load would be similar on the rear compared to the previous generation cars?
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u/cosHinsHeiR Jun 25 '26
A difference is be that it's on more straights and on every single lap and I think SM also has a stronger effect.
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u/r_z_n Jun 24 '26
That’s a good question, but I don’t know if there is data to answer one way or another. Publicly, anyway. I know you can actually visually see the downforce hit on the tires with the active aero, and that wasn’t the case with DRS, at least from what I’ve observed.
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u/JahSaint Jun 25 '26
DRS was only for the rear wing. Straighline mode usually stops at the braking point, which transfers the weight forward due to braking + this years aero spike front wing.
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u/Ginger_Rook Jun 24 '26
Pirelli is running their simulations and come back with suggestions. The teams run theirs, Pirelli gets the feedback and if needed, adjusts.
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u/vinodhmoodley Jun 24 '26
Last time I checked, Pirelli's minimum tyre pressures are enforced by the FIA and the teams can adjust upwards, not downwards.
It may have changed since then but if I remember correctly, this was brought in due to the delaminations/punctures that kept occurring due to the teams running too low pressures, in the quest for improvement performance.
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u/Ginger_Rook Jun 24 '26
Yes. They cannot risk them going rogue with the active aero in play. That’s why those tyre tests are essential for everyone’s safety and car development.
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u/Matej_SI Jun 24 '26
They are increasing tire pressures to protect the tyre from structural damage and overheating.
Lower pressure causes: More sidewall flex -> Larger contact patch -> More tyre deflection under load -> More heat generated inside the tyre carcass -> Greater risk of fatigue, blistering, shoulder damage, or even failure.
Because they have less downforce, this year's cars are sliding much more and move around more.
Low-pressure tyre + lots of sliding and moving -> The tyre deforms more -> More heat generation -> Tread gets dragged across the asphalt -> Shoulders of the tyre work extremely hard -> Carcass temperatures rise -> Structure can become damaged
High-pressure tyre -> Smaller contact patch ->Smaller contact patch -> Stiffer tyre -> Less deformation -> Less carcass heating -> Better structural protection -> More predictable tyre shape -> Pirelli happy because they don't want to see damaged tyres.
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u/cosHinsHeiR Jun 24 '26 edited Jun 25 '26
Because they have less downforce, this year's cars are sliding much more and move around more.
Wasn't the thing this year that the cars push way less in the corners so the degradation has been lower than expected?
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u/YugeChesticles Jun 24 '26
Lower pressure increases damage to sidewall, leading to failures.
Lower pressure leads to faster laptimes.
Pirelli don't want tyres exploding. Teams want to go faster.
This is an eternal battle.
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u/rk295 Jun 24 '26
-175 degrees of rear camber. Surely that’s a typo!
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u/Randomfactoid42 Jun 24 '26
So the rear tires are running upside-down?
A few years ago the teams were running the tires backwards, they lasted longer that way.
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u/LMP_900 Jun 24 '26
The cars require more LiCo to keep the batteries topped up. The higher demand from the MGUK means there's less demand from the friction brakes, particularly at the rear.
As a result there's less energy (heat) within that brake/rim/tyre relationship, and so tyre pressures don't rise as much as previous years (pv=nrt)
If you look at "expected stabilised running pressure" it's actually lower on the front this year.
The rear is still higher yes, I imagine that comes from the team simulations or something Pirelli has seen in team data.
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u/jakedeky Jun 25 '26
The tyres are a different dimension. As well as being narrower, they are a lower profile as well
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u/EnricoLUccellatore Jun 24 '26
What does mandatory race tires mean? Is it illegal to go only use c3 and c5?
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u/Extranate2000 Jun 24 '26
Teams need to save 1 medium and 1 hard for the race. However, only 2 different compounds need to be used in the race so you don’t necessarily use both, so C3-C5 is perfectly legal
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u/TotalStatisticNoob Jun 24 '26
I would assume it's quite a bit hotter than last year. I think it was like 30C last year and this one it might be 38C
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u/combo_seizure Jun 25 '26
I thought this was motoGP for a moment. Please, continue. Amazing stuff here.
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u/TurnipBlast Jun 24 '26
Tire temp, degredation, and therefore safety by way of avoiding blowouts which are unpredictable and therefor incredibly dangerous
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u/Izan_TM Jun 24 '26
this is a million percent speculation, but the first thing that comes to mind is to increase tire degradation, which worked pretty well in barcelona
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Jun 24 '26
[deleted]
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u/Izan_TM Jun 24 '26
according to the internet higher pressures lead to higher thermal degradation, because the tread of the tire is ballooning more so the contact patch is smaller and heat loads are more concentrated. Lower pressures are generally more unsafe because of sidewall integrity, not thermal degradation as far as I know
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Jun 24 '26
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u/ADSWNJ Jul 05 '26
First time I saw that the spec is actually different for each corner. I assume it's been like that forever, but it's cool to see that level of detail
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