Q What tyre pressure should I be using?

The Continental tyres on my Autocruise (Peugeot Boxer) motorhome have 65 psi on the sidewall. But they also show (in smaller characters) a maximum permissible pressure of 75 psi. Am I right in thinking when the ’van is fully loaded it is safer to run at the higher pressure?

Nick Harvey

A

As ever, it’s not that simple! Setting the correct pressures is best done with a weighbridge: you can’t set accurate pressures if you don’t know the weight of each axle when the ’van is fully loaded with all your personal accessories. Visit a weighbridge, weigh the front axle, then the rear axle (or the whole ’van and subtract the front axle weight from the total weight).

Many motorhomes travel very close to their maximum laden weight or even over it, so you need to know this weight. As a driver, you are responsible for knowing this weight – you can be fined if stopped and the vehicle is found to be overweight.

With modern base vehicles getting increasingly heavy and gadget filled, motorhome makers have a constant battle trying to make the habitation section as light as possible.

Armed with these axle weight figures, contact your tyre maker and ask for its recommendations. Keep these beneath the maximum inflation pressures detailed on the sidewalls.

Once inflated correctly, monitor how the tyres wear. If they are wearing evenly across the tread, the pressures are correct. If there’s wear at both edges but not the centre, it’s underinflated. If they wear in the centre but not at the edges, it’s overinflated. Any wear on one edge alone means that either the tracking or alignment is out – have a garage check it.

Peter Rosenthal