392 Tire Pressure Off-Road

Jgc650i · Feb 21, 2023

I know consensus is never going to happen with different opinions and different overall vehicle weights, tire sizes/types, mods, etc., but curious to see range of opinions on aired-down pressures for different off-reading types with the 392. In this case I’m thinking more specifically (and selfishly) to a 392XR with the stock 315 A/T tires/wheels, stock suspension, plus added weight of basic mods like winch, upgraded sliders, and skid plates. For this type of general setup, where would you target PSI for wheeling:

-Basic Trail
-Mud
-Beach/Sand
-Rock Crawling

dog · Feb 21, 2023

Jgc650i said:
I know consensus is never going to happen with different opinions and different overall vehicle weights, tire sizes/types, mods, etc., but curious to see range of opinions on aired-down pressures for different off-reading types with the 392. In this case I’m thinking more specifically (and selfishly) to a 392XR with the stock 315 A/T tires/wheels, stock suspension, plus added weight of basic mods like winch, upgraded sliders, and skid plates. For this type of general setup, where would you target PSI for wheeling:

-Basic Trail
-Mud
-Beach/Sand
-Rock Crawling

Last time I went out, we did a combination of rock crawling and mud (and snow). I put pressure down to like 15ish PSI on the XR wheels (no beadlocks). It did great.

So long as you don't hop back on the highway, or get super unlucky with just the right pinch, that seemed a pretty safe pressure. I used to push my 37" MTR Kevlars to like 11-12PSI with no beadlocks and some serious crawling, and I never lost a bead, but every wheel/tire/situation is different, and I haven't had a good opportunity for regular testing yet.

Fast-n-Furious · Feb 21, 2023

Great questions! I’ll be taking my 392 XR to some moderate trails in June (for the first time) and have been reading a lot on the tire pressure. I’ve decided to do 18 psi and give it a bit more room on the safe side with my wife and two kids in the rig.

Tank2112 · Feb 22, 2023

My experience would say, for slow rock crawling or offroad driving 12psi - 13psi minimum. However, at that low of pressure you have to be careful then descending off a steep obstacle and turning very sharp.

guruman · Feb 22, 2023

I'm not so hardcore these days. Airing down for me is more about making the ride more comfortable than it is increasing traction.

I have some delators set to somewhere between 15-20, I usually just install them when I want to air down (sometimes I just do not bother).

I had AEV beadlocks on my JKUR, and once or twice I played with running down in the single digits to help smooth out a rough trail.

Viking Jeeper · Feb 22, 2023

This is in my LJR so much lighter vehicle but a data point anyway. I air down to 12 PSI with the same KO2's an XR comes with. I air down even on trails that would not require it because it significantly softens the ride. There is a deep sand area where we often go and as much as I have tried I have never been able to get stuck, in 2WD with tires aired down.

7.62x392 · Feb 22, 2023

I usually run about 14-15psi on the trails.

Mouse · Feb 22, 2023

Oh boy, I feel another XR vs non XR discussion coming on.

@WhiteBronze392 · Mar 20, 2023

What's your go to air down tool?

Jgc650i · Mar 20, 2023

mbdurham said:
What's your go to air down tool?

Have been using a Boulder Tools Rapid Deflator. It’s worked well for what it is. Just bought and about to install the Innovative AT 4-Tire setup with the ARB compressor and Bluetooth controller.

Viking Jeeper · Mar 20, 2023

mbdurham said:
What's your go to air down tool?

Coyote deflators.

guruman · Mar 20, 2023

mbdurham said:
What's your go to air down tool?

I've had some screw on ones I've used forever. Adjustable pressure, just remove the stem cap, and screw on the deflators and drive away... no need to wait around for each tire to reach a target pressure. As you drive they deflate to the set pressure and stay there.

Found the link. Amazon says I bought these in 2010:

https://www.amazon.com/gp/product/B001IBQQFS

Viking Jeeper · Mar 20, 2023

guruman said:
I've had some screw on ones I've used forever. Adjustable pressure, just remove the stem cap, and screw on the deflators and drive away... no need to wait around for each tire to reach a target pressure. As you drive they deflate to the set pressure and stay there.

Found the link. Amazon says I bought these in 2010:

https://www.amazon.com/gp/product/B001IBQQFS

Thats what I like about them but you do need to take them off before you hit rocks or something can can rip the stem out. Two guys I wheel with both have the ARB tool that removes the valve core. Way too much trial and error in that system.

guruman · Mar 20, 2023

Viking Jeeper said:
Thats what I like about them but you do need to take them off before you hit rocks or something can can rip the stem out. Two guys I wheel with both have the ARB tool that removes the valve core. Way too much trial and error in that system.

Yeah, I usually will take them off if doing much in the rocks or deep mud. These days though, I mostly air down to make forest roads more comfortable, and not necessarily to gain traction. For that I can just leave them on and remove them when I air back up.

I do wish someone made something similar that did not stick out as much, like built into the space of a standard stem or something.

Viking Jeeper · Mar 20, 2023

guruman said:
Yeah, I usually will take them off if doing much in the rocks or deep mud. These days though, I mostly air down to make forest roads more comfortable, and not necessarily to gain traction. For that I can just leave them on and remove them when I air back up.

I do wish someone made something similar that did not stick out as much, like built into the space of a standard stem or something.

I agree in making forest roads more comfortable. It took me a while but I finally convinced the last guy in our group to start airing down. He would always say we dont need to. I know we dont need to but it makes it so much nicer and we always hang out and talk after a ride anyway so now we just air up during that time also.

I think I have seen (probably very expensive) wheels that have a separate air down valve built in.

Ted392 · Mar 20, 2023

Airing down/up is part if the fun in offroading with friends. It's bs time and enjoy the sights.

For many years, I've just air one tire down by pressing the Schrader valve in and count the seconds it takes to my desired psi. Then I do the others via the same time. Pretty accurate. Then recheck with guage.

guruman · Mar 20, 2023

Viking Jeeper said:
I agree in making forest roads more comfortable. It took me a while but I finally convinced the last guy in our group to start airing down. He would always say we dont need to. I know we dont need to but it makes it so much nicer and we always hang out and talk after a ride anyway so now we just air up during that time also.

I think I have seen (probably very expensive) wheels that have a separate air down valve built in.

There's these, which I think you can add to almost any wheel.

https://powertank.com/collections/monster-valves

byhumba · Mar 20, 2023

ARB deflator for different PSI settings (snow/mud/sand/rocks), and Coyote deflators for 10 PSI. I use that PSI on my TJ (no beadlocks and 33" GY Duratracs) most times. I have lowered my 392 non-XR 33" KO2s to 15 PSI. Which reminds me, I need to get another Coyote set for that 15 PSI.

byhumba · Mar 22, 2023

So, Coyote deflators are discontinued! Gladly, I found a new set on Ebay. Most deflator brands similar to Coyotes, vary in accuracy too much to trust them. Some vary as much as 2 PSI from what they are set. The Coyotes have given me a variation of about 0.25-0.50 PSI, but my pressure gauge can play a factor in that variation as well.