Air down to what psi?

[James Deaton]

Hey guys...

New (to us) 2002 Mitsubishi Montero XLS overland rig this year. Here are some specs:

Curb Weight: 4600lbs
Tires: New Cooper Discoverer AT3 265/75/16
Wheels: Stock aluminum (NOT beadlocks)
Trail types: Washboard dirt mixed with small rocks

What would you guys air down to?

*Yes we have a compressor to air back up.

James

 

[madcratebuilder]

15-18psi depending on surface, if I'm dealing with large rocks it's 15psi for sure.

 

[James Deaton]

How about doing 40mph on washboard fire roads?

 

[Wanderlost]

For what you are using it for and the tires you have, 25 should give you a nice ride on rough gravel. Going lower may cause damage to the sidewalls over time.

 

[madcratebuilder]

How about doing 40mph on washboard fire roads?

I would try 20-25psi and see what feels best. The 265/65r17 p rated duracraps on my truck give a fairly soft ride below 25psi. It may be that a stiffer sidewall like LT or E rated may be better with a lower pressure. If you have a cheap infrared temp gun you could compare sidewall temps at different psi's. I would think the more sidewall flex the higher the temps.

I'm new to low pressures and offroad tires but have 40+ years of doing 14X32 slicks at 8-10 psi@150+mph. Those things have painted toilet paper for sidewalls.

 

[toxicity_27]

I'll echo some of the suggestions and say 20-25 psi. Look to see what the bulge looks like when you're airing down, get out and feel the sidewall when you're driving. If it's too hot to keep your hand on it, put more air in.

 

[James Deaton]

Alrighty. Good advice all. Thank you!

James

 

[Jorrie]

It all depends on what terrain you are going to drive. In general i let out 1/4 for gravel and 1/2 for sand.