When to Air Down, Preferences, Opinions, and Discussion

[DocMike]

Dug around and did not see this one. Been playing a lot in the mountains. We have lots of sand out here and I know airing down for sand is wise. I could tell on the last trail I was on that I probably should have dropped my PSI as I could feel some slippage and encountered some softer areas on the trail. The one before that was comprised of lots of loose and jagged rocks. In both instances I think the Jeep was just awesome. I went slow and picked good lines, spotted tires etc.... But I could have done better.

That being said, I know there are super experienced 4wd people on here. My assumption is that time and experience will teach, but some general guidelines would be great. My hope is to generate some robust discussion on this topic and allow those of us with limited off roading to read and ask questions.

Under what conditions do you choose to air down?
How much do you drop in PSI?
Do you factor load in the bed or on a trailer when deciding?
How much is acceptable when running non bead lock rims vs. bead locks?
How does this vary with sidewall height? Like I have a 17in rim and 33s, would it be different with a 20in rim and 33s?

Thanks! I'm digging the journey.

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[Be.Zick]

Im probably wrong here but what I do is:
I live in the desert so i always air down.
If its going to be a long day of wheelin I go down to 14 psi.
This is my first truck so not sure if going down to 14 is good with a load in the bed. I would air down a trailer as well. Not to sure on what psi a trailer should be though.
Never go past like 11 psi on a non bead lock rim. I would avoid a bead lock unless you are planing on doing a lot of rock crawling.
And a larger sidewall is always better. You'll have more "spring" in your tires and more of a foot print on the ground.

 

[361Sean]

Pretty much anytime you are on a trail it's not a bad idea to air down. Somewhere around 15 psi should be good. You'll notice the jeep doing g much better all around.

 

[DocMike]

Can you get away with 15 psi without a bead lock? For street use my 33s are at like 39-40.

Pretty much anytime you are on a trail it's not a bad idea to air down. Somewhere around 15 psi should be good. You'll notice the jeep doing g much better all around.

 

[SloW8]

15 psi makes for a way better ride over anything rougher than a flat and smooth dirt road. Don’t need bead locks at that pressure. You will likely get decent sidewall flex that will help with traction.

If I’m on a wheeling trip like in Moab, I will leave it at that pressure and drive on the road up to about 50mph but not for a long distance. Have driven that way for 20 min or so without feeling any heat in the sidewall.

 

[SloW8]

15 psi makes for a way better ride over anything rougher than a flat and smooth dirt road. Don’t need bead locks at that pressure. You will likely get decent sidewall flex that will help with traction.

If I’m on a wheeling trip like in Moab, I will leave it at that pressure and drive on the road up to about 50mph but not for a long distance. Have driven that way for 20 min or so without feeling any heat in the sidewall.

Gotta add - this is on 35” and 37” tires. If you have less sidewall, you may wanna run 18-20lbs.

 

[DocMike]

Good to know. I will play with this on my next adventure. I'm looking at onboard air systems lately.
The Jeep ran up to Crystal Mill over some seriously rough terrain and jagged rocks at 40 psi in the 33s with zero issue.. was bumpy as hell though. But it just went for it. Just clawed itself over anything. But like I said, I want to be better and smarter about things..

15 psi makes for a way better ride over anything rougher then a flat and smooth dirt road. Don’t need bead locks at that pressure. You will likely get decent sidewall flex that will help with traction.
If I’m on a wheeling trip like in Moab, I will leave it at that pressure and drive on the road up to about 50mph but not for a long distance. Have driven that way for 20 min or so without feeling any heat in the sidewalk.

 

[DocMike]

I'm on a 33 with stock rims.

Gotta add - this is on 35” and 37” tires. If you have less sidewall, you may wanna run 18-20lbs.

 

[SloW8]

I'm on a 33 with stock rims.

I’d do 20. You will like the ride soooo much better.

 

[sass JT]

I live up in foco and have wheeled a bunch here in Colorado... here’s my take.

If your stock, you can safely go down to 15psi (as long as your not trying to be one of those guys that fast is the only way on the trail). It will give you the benefit of softer ride and more rubber on rocks

if your 35’s or 37’s with aftermarket wheels, you could go as low as 10psi but myself on 37’s have my deflators set to 12-13 psi. I don’t want to take the chance of loosing a bead.

Here’s the big rub though... when you air down you do loose ground clearance, so if you go too far down... you have a better chance of hitting things underneath.
The more times you go offroad and play with your tire pressures the more confident you become to know what your rig can handle in the current state of your vehicle... ie stock or modified.

 

[DocMike]

That's what I was wondering. I know you do lose ground clearance when you air down. Eventually I will run 37s and a lift. But I want to swap the gearing to something lower for that. I'm not gonna "new bronco" it down the trail. I'm looking at the ARB systems right now. I think that may be the way o go. Have onboard air.

I live up in foco and have wheeled a bunch here in Colorado... here’s my take.

If your stock, you can safely go down to 15psi (as long as your not trying to be one of those guys that fast is the only way on the trail). It will give you the benefit of softer ride and more rubber on rocks

if your 35’s or 37’s with aftermarket wheels, you could go as low as 10psi but myself on 37’s have my deflators set to 12-13 psi. I don’t want to take the chance of loosing a bead.

Here’s the big rub though... when you air down you do loose ground clearance, so if you go too far down... you have a better chance of hitting things underneath.
The more times you go offroad and play with your tire pressures the more confident you become to know what your rig can handle in the current state of your vehicle... ie stock or modified.

 

[kickingaz]

I am in the desert in Arizona and we have a great deal of rock on our trails. I generally air down to about 12-14 pounds on stock wheels, with my beadlock wheels I can go down to single digits. This isn't necessary for most trails but helps when I am doing more extreme trails. I don't anticipate I will be able to do the same trails in AZ and Moab with the Gladiator that I did in the Wrangler Rubicon.

 

[BLK HOLE]

I'm quick to decide to air down, with onboard air and the ease of airing down within a minute or so I'll pull the air out in heartbeat. For DD'ing I'm only @ 26-27PSI as it is.

Under what conditions do you choose to air down? - If I am slipping and/or the road is washed out and I need a smoother ride.

How much do you drop in PSI? - Ranges - I go down as far as 10psi for rock climbing. 12-15PSI for easy/mild wheeling and 15-20psi for washout roads.

Do you factor load in the bed or on a trailer when deciding? - I wouldn't air down if the truck had a heavy load in/on it. I probably wouldn't be wheeling at the time, save a washout road condition. In which case yes, I would factor it in and stay as inflated as I can tolerate.


How much is acceptable when running non bead lock rims vs. bead locks? - I don't have BLs and I clumb rocks at 10psi fine.

How does this vary with sidewall height? Like I have a 17in rim and 33s, would it be different with a 20in rim and 33s? - Yes...the more sidewall mass of air you have the better.

 

[Sportsbiz]

I’d do 20. You will like the ride soooo much better.

Desert dweller on a JTR with stock wheels and tires (33's). I air down to 20 as well.

 

[WSU JKU]

What you air down to really depends on the terrain and on your tire/wheel combo.
For most trails, I go down to 12-15psi (run 28psi on the street for my 37-12.5-17 BFG AT). In the snow, I'll go 8-10 or even less, if needed. Sand is usually similar to snow, you can get away with less pressure than rocky trails.

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