I am in the UK. My car is specified to have a tyre pressure of 26 psi front and 29 psi back.
I had pumped up the tyres in warmer weather when the air temp was about 18 to 20 C. I would probably have driven about a mile or more to the filling station to pump up the tyres so by then the tyres would be warmer.
Today the air temperature is about 3 C. I took a tyre pressure reading (using my usual digital tyre pressure meter) after the car has been standing for over 24 hours.
All the pressure readings today seemed a bit low. They were about 4 to 5 psi lower than specified. i can't think that all four tyres had leaked by a similar amount.
Is this pressure difference mainly due to the effect of temperature? I ISTR something like Charles Law allows this to be calculated although there seem to be some other variables too.
Can anyone advise?
Thank you.