Why must I check the tyre pressures when cold?
The temperature inside the tyre rises during use, increasing the pressure by as much as 20%. This is normal and is allowed for in the design of tyres, but if you adjust pressures to the specified figure with the tyres warm, the result will be under-inflation. Car tyres are considered to be cold when they have not been run for at least one hour, although you should still be okay to check the pressures after driving at low speed for a maximum of two miles (three kilometres). Check out our reviews of car tyre pressure gauges to see which are most accurate.
