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2022 mk8.5 ST3
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Discussion Starter · #1 ·
Just curious what everyone's tyre pressures are while the car is unloaded.

Are there benefits to running the pressure near 30psi for better grip etc? (mine are set both to 34psi)
 

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Fiesta MK8 ST3 MY2021
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501 Posts
Mine are (bar):

Front: 2.8
Back: 2.7

Dealer spec and took a ride an hour or two ago and still 30 degrees, more or less, so I need to have a look again when the temperature is back to normal...

Also read them in FordPass PRO app on my Android Phone just now
 

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The pressures go up quite a bit once you drive the car.
So, I suppose they should be set "cold".
Would the recommendations be for a standard temp like 20C?
 

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The pressures go up quite a bit once you drive the car.
So, I suppose they should be set "cold".
Would the recommendations be for a standard temp like 20C?
For optimum use we should be checking and adjusting the pressures very regularly and always when the tyres are cold (as in not driven yet), its in the manual.

In a temperate climate air temperature shouldn't change much between those checks so always just set them to the manufacturers spec. before setting off and they'll be fine until the next check... irrespective of the air temperature when you set it.

Oh, and of course never adjust your pressures when the sun has been on the car. There'll be a hefty imbalance of tyre surface temperature between the sunny and shady sides of the car.
 

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Back cigarette packet says 10oC difference in cold set pressure is about 1.5psi.
So if you set them at 36psi on a 10oC morning, and check them in the afternoon when it’s 20oC, they’ll be 37.5psi
Whether that’s remotely relevant of course...
 

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2005 mk6 Fiesta ST
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Dropping pressures for grip isn't really the right thing to do, you'll just make the sidewalls roll under the wheel that's on the outside of the turn. When cornering hard the load on the tyre will be high so you don't want it underinflated.

Earlier this year I ripped a tyre off the rim when it was underinflated (on a motorsport event on a closed course, just after the start line so wasn't travelling fast or it could have been pretty serious)
 

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Fiesta MK8 ST3 MY2021
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Ok in not-driven condition... 2.4bar
 
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