Winter tyre pressures?

[Isaac]

Just fitted winter tyres. Plate on door has different tyre pressure recommendations to the onboard computer. See attached pictures . Not a small difference either. Thoughts? Q

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[Tooney]

https://static.nhtsa.gov/odi/tsbs/2025/MC-11015166-0001.pdf

 

[69Mach390]

The chart is nice but it still doesn’t answer the question as to what to go by- the computer or the panel/chart.

I’ve also never had a car suggest different tire pressures depending on how loaded the car is. Would anyone actually pump up or air out the tires based on people riding in the back?

 

[Fogsvans]

I’ve also never had a car suggest different tire pressures depending on how loaded the car is. Would anyone actually pump up or air out the tires based on people riding in the back?

All my cars from at least 30 years back recommend different tyre pressure depending on load. Of course noone pump up or air out every day but it gives an indication and if one is going for a road trip with full load in the car, it's a good idea to pump up the pressure a bit.

 

[W1NGE]

Just fitted winter tyres. Plate on door has different tyre pressure recommendations to the onboard computer. See attached pictures . Not a small difference either. Thoughts? Q

The plate is for summer tyres only depicting full load and half load - whatever was fitted to the car originally on leaving the factory and not any subsequent changes to wheel size.

On the PCM select the correct tyre size and type which match the wheels / tyres you are fitting and use the given pressure settings.

 

[Midlifecrisis]

I put winters on mine a couple of weeks ago. 20in wheels on a ‘23 turbo. Pressures in the computer are the same as my summer tyres (also 20in) - but different to yours. 2.7 front, 2.5 rear for part load

 

[69Mach390]

All my cars from at least 30 years back recommend different tyre pressure depending on load. Of course noone pump up or air out every day but it gives an indication and if one is going for a road trip with full load in the car, it's a good idea to pump up the pressure a bit.

Interesting, must be a European car thing then. All my previous and other cars were/are American or Japanese.

Here is what the plate looks like on my Ford Mustang GT-

 

[kern417]

a lot of german cars do that. it's based on tires/temp but also average speed, since most winter tires can't be driven as fast as summer tires. so you adjust the pressures to match. same reason a lot of cars have a max speed setting/warning, so you know if you're on the autobahn you can't cruise as fast on winters. even our volkswagen has a setting for it.

 

[Beattie]

I set what the PCM suggests for both my summer and winter tyres. Not had any issues.

 

[whitex]

I set what the PCM suggests for both my summer and winter tyres. Not had any issues.

Full load or half-load?

 

[Beattie]

Full load or half-load?

Half load. Unless I’m doing a long trip loaded with the family and cases, which is quite rare normally.

 

[Isaac]

Spoke to Porsche dealer about the right pressures. Answer was to ignore the door plate ("which is a legal requirement") as it is a generic pressure recommendation for the base model that does not take account of things like air suspension or springs etc. which make a difference to weight. So they say always go by the onboard computer "which is car specific" - which in this case is 3 bar different. So there we have it.

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