Air hose pressure warning

All car tyres should come with an additional 'warm' pressure rating - that's the view of a leading motoring organisation

Auto Express Car Reviews

28th May 2007

The IAM Trust has revealed that nearly two-thirds of motorists use filling station air hoses to monitor and inflate their rubber. However, this means the tyres will be warm - and the pressures printed in the owner's manual are for cold ones.

"The danger is that the drive to the filling station increases tyre pres-sures significantly," explained Tim Shallcross, the Trust's head of technical policy. "People will be pumping up their rubber to a level they believe is correct, when in reality their tyres can end up being under-inflated by 12-15 per cent, because air expands when it is heated."

The accuracy of filling station air pumps has improved. In 2005, half gave incorrect readings, according to the IAM Trust, but now 80 per cent deliver pressures to within 2psi. Nevertheless, Shallcross is calling on makers to give two recommended psi figures in vehicle handbooks, and is also telling owners to buy their own gauge and check their rubber more frequently at home.