Dual rear wheels off road

Hi Jay,

In my understanding there are 2 reasons to why you should deflate your tyres in some circumstances.

The first is to provide more surface area on the tyre in contact with the ground in sandy terrain to stop getting bogged, duel rear wheels will of course have twice the surface area in contact with the ground and may be ok at normal pressure, depending on the load carried. The first thing to do if bogged in sand is to let the tyres down, a simple thing to do that could have saved lives of quite a few travellers over the years who bogged a vehicle and perished. When rescuers arrived, they let the tyres down and drove the vehicle away.

The second reason is to provide a softer ride on corrugations, in this case duel rear wheels would be of no benefit at normal pressures.

I think that you would have to experiment a bit and see what the lowest pressure is that you can get away with before the tyres touch.

Paul.

How far apart are we talking Jay?

Airing down will decrease the circumference slightly anyway and the tyres won't exceed their orignial horizontal dimensions by much at all when absorbing the bumps. Air down the rear tyres on the F250 and watch them go over a speed bump.

As far as offsetting the deflation just think of the tyres on a dual axle as having four big air bags to play with instead of two. As to what pressure is best it'll be trial and error just like with a van and depend on two things, what sort of weight they end up carrying and the speed you travel at.

Barry