A learner asks why tyre pressures should be checked when tyres are cold rather than after a long drive. The correct explanation is:

1. It is simply tradition with no technical reason
2. Driving heats the air in the tyres and raises the pressure, so a hot reading is falsely high and could lead to under-inflation if air is released to match the specification
3. Cold tyres are easier to reach
4. Pressure does not actually change with temperature