At what temperature should I set my tyre pressures?

Gay-Lussac's law of gases put simply is - in a given volume of gas (e.g in a tyre) the pressure is in direct proportion to the temperature. So as temperature increases so pressure increases and vice versa.
Therefore at what temperature should tyre pressures be set?

Asked on 17 June 2022 by willboy

Answered by David Ross
Good question. The usual advice is to check or set tyre pressures when tyres are 'cold' - in other words when the vehicle hasn’t been driven for at least two hours. The normal ambient temperature here would be 20°C.

For every decrease of 1°C, tyre pressure drops by approximately 0.19 PSI. So a good rule of thumb is that for every 10°C drop in temperature, tyre pressures will drop around 1 to 2 PSI.
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