Joe replied:

With these LT construction tyres you have significantly greater room to play when considering tyre pressures. Please note (anyone out there reading this) that people with normal radial construction tyres should not exceed the 36psi pressure.

So, with your BFGs - well, as always it will be a compromise and changing anything will affect other components in the same area. For example, higher tyre pressures will reduce the damping effect that a tyre has on "bounce" in the system. This means that the damper (shock absorber) will have more work to do, so you need to keep an eye on these components. Additionally, if you have stiffened the springing in the vehicle you may have to consider this aspect too.

But, back to the point of your question - recommendations.

I have not driven a 'roo for any distance, but it should not be too different to my Pajero, so my recommendations for those tyres would be:

High speed bitumen : 38ps front and 42ps rear
Fast dirt/gravel : 36psi front and 38psi rear
Slow(er) tracks : 34psi front and 36psi rear

For most vehicles you would try to keep the pressures front and rear the same, or close to it, but the 'roo has some pretty vague steering characteristics that are helped by trying to damp them out using softer tyre pressures.

The higher pressures for the higher speeds on smooth bitumen will give better fuel consumption, but watch the grip levels deteriorate well beyond what you might expect if it gets wet.

If you venture off the bitumen you need to reduce tyre pressures to try to avoid those impact punctures - let the tyre deform a little when it hits a rock.

If in doubt, use lower pressures and slow down!

Good luck

Joe

MARK C,SYDNEY replied:

Mike, I agree with Joe except that on rough tracks I would lower my pressures down to 30psi or even lower and reduce speed.I learnt this from the boys over a beer at William Creek pub and after taking their advice have done over 10 years of outback touring without one flat tyre.In fact I've put 360,000 klm on my 4runner and am only on my fifth set of tyres(Goodyear Wrangler A/T).I believe speed combined with vehicle weight causes tyre wear and tear thats why I take it easy,and tow a trailer with all the heavy gear in it.

Brett replied:

I agree that lower pressures on dirt/ rough roads make travelling much more comfortable.
We recently did the Bloomfield track in our old Troopy and were getting vibrated into a million pieces by the corrugations, so I dropped the tyre pressures down to 24psi and it was like driving a different car.

I run Desert duellers and was fortunate enough a couple of years ago to hav a chat with a Bridgestone Technician and was advised that optimum tyre pressure for a 10R 15 willhave a 4psi differential between cold and its operating temperature. This only applies to sealed roads.

Remember that to maintain this hot/cold variation any increase in vehicle load will alter the tyre pressures.