Cold weather tyre pressure warning

[Jeremy]

I got a tyre pressure warning today and checked them.

Oddly - they were all down by exactly 0.5bar 1.8/1.8 2.3/2.3

Since it's the coldest day of the winter in UK today at around 3degC - I'm wondering if this is just a temperature effect rather than leakage.

Anybody else seen this at similar temps?

 

[jadnashuanh]

All tires lose air pressure with a drop in temperature. Figure about 1 pound per 10-degrees F (leave the conversion to you!). THen, they do tend to lose a little bit over time just sitting there, especially if you don't have the caps on tight (the better ones have an o-ring or other seal in there to help prevent air loss as the valves are rarely perfect, that gives you two seals to help mitigate any losses).

 

[Jeremy]

Yes, I understand that - but I've had a lot of cars in my life and never seen the pressures drop at exactly the same rate in all four wheels.

 

[jadnashuanh]

Yes, I understand that - but I've had a lot of cars in my life and never seen the pressures drop at exactly the same rate in all four wheels.

They would be much more likely to drop the same in a short time based on temperature than they would over a longer timeframe based on any leaks. Driving it, as you probably know, will also change the temperature, often by a lot, based on how far and how fast, and how aggressively you drive. One side sitting in the sun verses the other in the shade can make some significant differences, especially in the winter where the black rubber can absorb a fair amount of heat.