Tyre Pressure During Hot Weather.

[SparklyKid]

When is the best time of day to check the tyre pressure during this very hot weather.
I would have thought early morning with car in the shade.
Does the pressure increase if the tyres are in direct sunlight all day ?

[woofgang]

That's what I have always understood although not sure how much difference it makes in practice

[SparklyKid]

Might just try checking tonight about 10 pm and again at noon tomorrow.

[dannyk13]

Info here:-
https://www.driverknowledgetests.com/resources/how-the-temperature-and-weather-affects-tyre-pressures/

[SparklyKid]

Thanks danny. Is this a typo ?

it’s the air in the tyres, and it’s usually kept at a temperature of around 32 PSI

[IJKLM]

The best time to check pressure is, rather obviously, just before you intend to drive the vehicle.

In practice, an increase in temperature from 10C to 30C will increase pressure by around 7 percent. From around 2.6 bar to 2.8 bar.

Since most people drive slightly under inflated, it's not really worth worrying about.

But if you want perfectly accurate pressures, then check pressure just before you start using the vehicle and adjust accordingly.

[SparklyKid]

Thanks ijklm, sounds sensible.

[Electrochem]

I always check my tyre pressures with a decent gauge. I know people who will drive 5 miles to a petrol station to put air in their car tyres, using equipment that is usually knocked about and unreliable as far as pressures are concerned. Tyres should always be checked when they are cold and driving to a petrol station will warm them up. I would be inclined to check them when they have been in the shade for some time. Many people never check their tyres for faults and wear, let alone pressure.

[SparklyKid]

Thanks, Electro. I do have a digital pressure guage, seems very accurate