Tyre pressure

LoGiC_91

Active Member
Mar 6, 2021
32
8
Sweden
Hey peeps!

I've always followed what it says on the fuel flap for tyre pressure but I'm curious about two things:

Is the stated tyre pressure for warm tyres (e.g. for low loading manufacturer states 2.7 bar front and 2.4 bar rear and I usually check this at a fueling station after driving for a bit)

I live in Sweden so I'm rolling on winter tyres half the year, which is a change from 235/35 R19 (summer) to 225/40 R19 (winter). Do I need to consider anything else here or just match the specified pressure written on the fuel flap?

Thanks in advance :)))
 

BoomerBoom

Active Member
Jun 1, 2018
690
249
Tyre pressures should be checked when cold, before you've made any journey that day as the pressure will always increase with heat. The guide value should be the lowest possible that the tyre can be, if you set that pressure when the wheel & tyre are warm then it will drop lower as it cools - leading to a risk that the tyre will deform and overheat at speed.
 

LoGiC_91

Active Member
Mar 6, 2021
32
8
Sweden
Tyre pressures should be checked when cold, before you've made any journey that day as the pressure will always increase with heat. The guide value should be the lowest possible that the tyre can be, if you set that pressure when the wheel & tyre are warm then it will drop lower as it cools - leading to a risk that the tyre will deform and overheat at speed.
Great response, cheers! I'll bear that in mind.
 

xyz

Full Member
Feb 28, 2004
565
204
oxford
Visit site
Thanks for the response @Glosphil. I must ask however, is that just hear of say or do you have official sources/references. Don't the dimensions play a role?

If you look on line, lots of sites say to slightly increase pressures as it increases stability in the tyre and that improves grip.


Sent from my iPad using Tapatalk
 

TheSwede

Active Member
Oct 20, 2018
306
167
Sweden
A common rule is:

16" 2.6 bar
17" 2.7 bar
18" 2.8 bar
19" 2.9 bar

My mk3 have 235/35 19 winter tires an I have used 2.9 bar in all tires, the same for summer tires. (Same dimension).
This winter I haven't changed for winter wheels since the Cupra have been stored in a garage..
 

SEAT Rule

Active Member
Nov 19, 2019
188
62
Hello there,

as the other guys have mentioned you should always check/adjust tyre pressures when cold not hot.
Regarding winter tyres I've never had the need to fit any myself, as here in the UK down on the south coast of England hardly get any severe cold weather.

But if you feel you need winter tyres or full blown mud/snow tyres, reading some of the info on Dunlop, Goodyear and Michelin tyre websites, as all ready mentioned in previous post, it states ideally to adjust pressures either first thing in the morning or in the evening when the winter temperatures will be close to there lowest, at -4C° to -25C° based on coldest temperatures in Sweden, otherwise the tyre pressures have a risk of dropping slightly if set in temperatures above zero C°.
According to the info I've read every 5C° to 10C° drop in outside temperature, ideally you'll need to check/increase the tyre pressures up by 1 to 3 PSI per every 5C° to 10C° drop in temp.
To be honest this is really for severe winter weather where temperatures will fluctuate often between -5C° down to -45C° and driving in snow or on ice, in this case you'd want to check pressures on a daily basis.

I've found and attached an image of OEM tyre pressures for the MK3 Leon for none UK versions, so will apply to models in Europe including Sweden.
Green dots show tyre pressures for tyre size 235/35R19
And red dots for tyre size 225/40R18

You stated your winter tyres are 225/40R19

As long as you use the OEM standard tyre pressure setting as a base line, as stated in your car manual or fuel flap label you'll be fine.
It all depends how cold it is in Sweden where you are, and how often the temperature fluctuates, if it's hardly anything and the temperature is never really going below zero C°, then you'll be fine with the winter tyres you have, set at OEM standard tyre pressure setting stated on your fuel flap label, or set 1 to 2 PSI above standard setting is fine if you feel you need to in the winter.

Hope this helps
Si
 

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Glosphil

Active Member
Nov 10, 2004
412
175
Gloucestershire
A common rule is:

16" 2.6 bar
17" 2.7 bar
18" 2.8 bar
19" 2.9 bar

My mk3 have 235/35 19 winter tires an I have used 2.9 bar in all tires, the same for summer tires. (Same dimension).
This winter I haven't changed for winter wheels since the Cupra have been stored in a garage..
The manufacturers of many cars state different pressures for front & rear tyres even if of same size. My wife's Clio is 36F & 30R.
Sutely the overall weight of the car, its weight distribution & tyre size (width & profile) has more influence on suggested pressures than wheel diameter.
 

Mr Pig

Active Member
Jun 17, 2015
2,614
906
It's best to check the pressures at home when you've not driven anywhere. A decent tyre pressure gauge is cheap and I like a mountain bike floor-pump for adding air. Quicker and easier than a foot-pump or a plug in electric one.

You can get some idea of how far off your pressures are retrospectively by looking at the wear of your tyres. If you've been running too low, the tyres will wear at the sides. Too high and they'll wear more in the middle.
 
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LoGiC_91

Active Member
Mar 6, 2021
32
8
Sweden
Hello there,

as the other guys have mentioned you should always check/adjust tyre pressures when cold not hot.
Regarding winter tyres I've never had the need to fit any myself, as here in the UK down on the south coast of England hardly get any severe cold weather.

But if you feel you need winter tyres or full blown mud/snow tyres, reading some of the info on Dunlop, Goodyear and Michelin tyre websites, as all ready mentioned in previous post, it states ideally to adjust pressures either first thing in the morning or in the evening when the winter temperatures will be close to there lowest, at -4C° to -25C° based on coldest temperatures in Sweden, otherwise the tyre pressures have a risk of dropping slightly if set in temperatures above zero C°.
According to the info I've read every 5C° to 10C° drop in outside temperature, ideally you'll need to check/increase the tyre pressures up by 1 to 3 PSI per every 5C° to 10C° drop in temp.
To be honest this is really for severe winter weather where temperatures will fluctuate often between -5C° down to -45C° and driving in snow or on ice, in this case you'd want to check pressures on a daily basis.

I've found and attached an image of OEM tyre pressures for the MK3 Leon for none UK versions, so will apply to models in Europe including Sweden.
Green dots show tyre pressures for tyre size 235/35R19
And red dots for tyre size 225/40R18

You stated your winter tyres are 225/40R19

As long as you use the OEM standard tyre pressure setting as a base line, as stated in your car manual or fuel flap label you'll be fine.
It all depends how cold it is in Sweden where you are, and how often the temperature fluctuates, if it's hardly anything and the temperature is never really going below zero C°, then you'll be fine with the winter tyres you have, set at OEM standard tyre pressure setting stated on your fuel flap label, or set 1 to 2 PSI above standard setting is fine if you feel you need to in the winter.

Hope this helps
Si
Many thanks for your extensive response Si, especially the table you attached. It was very helpful :) I do need to get myself an air compressor eventually to be more flexible with changing tyre pressure, but I'm not quite there yet xD
 
Last edited:
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