• Welcome to H4O! For a reduced ad experience, please login or register with the forum.

How much do you air down?

kmug

Well-Known Member
Messages
116
Location
Lake Stevens, WA
I need to calibrate my staun tire deflators. I have an h3 with 33" toyo m/t tires. Is there a general rule of thumb?
 

06 H3

a.k.a. "The Jackal"
Messages
9,350
Location
Meridian, ID
depends on terrain. each tire has their "magic #" most are between 12-20 depending on if you have beadlocks or not I wouldnt go lower then 14-15
 

bebe

Moderator
Messages
1,375
Location
Dayton, NV
Yep, weight, tire size, terrain, traveling speed all play a role.

in a stock H3:

Dirt roads I would run 18psi if you are going to be going over 30 mph.

Slow speeds w/rocks 15psi

Sand Dunes/Deep Snow 12 psi
 

Paladine71

ΜΟΛΩΝ ΛΑΒΕ
Messages
1,483
Location
Tallmansville, WV
Normally between 18-20 running 35's on an H3. I like off camber so I keep it a little higher. We don't have sand around here, just hills and mud.
 

alrock

El Diablo
Staff member
Messages
10,442
Location
Scottsdale
Typically 18 psi for my wheeling, 25 ish on dirt roads just to soften the ruts. I've been at 15 with no issues, perhaps just too lazy to change my Stauns down to 15.
 

kmug

Well-Known Member
Messages
116
Location
Lake Stevens, WA
Typically 18 psi for my wheeling, 25 ish on dirt roads just to soften the ruts. I've been at 15 with no issues, perhaps just too lazy to change my Stauns down to 15.

D'oh! It never occurred to me to air down a bit just for dirt roads. I was on one of those forest service roads where runoff made it like driving on a washboard the whole time just the other day. I thought I was gonna burst a kidney.
 

3Hummers

Super Moderator
Staff member
Messages
10,398
Location
Central Texas
I go as low as 12 on rock, 25 on dirt to smooth out the ride and then whatever the terrain dictates from there. My trucks all have beadlocks.
 

Steve #1

Well-Known Member
Messages
534
Location
TEXAS
I need to calibrate my staun tire deflators. I have an h3 with 33" toyo m/t tires. Is there a general rule of thumb?

Yes. The genral rule of thumb is 25%.

There is not a pressure that will work with every vehicle and every tire so you must determine what that number is for your combination.

With the tire fully inflated, so the tread is making equal contact across the tire, measure from the ground to the bottom edge of the wheel. Air down until you have decreased this distance by 25%. Check the presure. Front and rear may be slightly diferent. This will be your base air down presure.


From here you can make changes depending on the terrain. For lots of sharp rocks you may want to play it safe and run a little higher. For sand you will want lower. You will find that as you go lower in PSI small changes will have effect than they do at higher PSI.
 
Last edited:

Kurt

Well-Known Member
Messages
955
Location
Orange County, CA
I run 18-20 psi on my beadlocked wheels and tires. HMMWV wheels with 37x12.5x16.5 MTR's on a 8300 lb truck.I'll run 35psi on the highways. I haven't gone lower than 18 but I probably would for sand dunes.
 

skeptic

Well-Known Member
Messages
737
Location
Orygun
I haven't don't anything I'd consider hardcore, but typically I don't air down at all. Sometimes down to 25 or so just to soften the bumps a little.
 

Flash

Well-Known Member
Messages
195
Location
Michigan
Running 33" Duratracs. I run 45psi on the highway and air down to 20psi for off road. In sand it was not enough and should have dropped more. In snow it worked fine. For mud it seems fine and for rock (especially wet rock) I slip off - so I might go lower. 12-20psi seems a good rule to follow. I think I would be hard pressed to get below 15 though. I am going with a different shock setup - so that may affect my future psi airdown decisions. My favorite terrain so far is snow. Minimal truck damage, beautiful scenery, and great traction.

eta...I carry a 15# CO2 tank to air up.
 
Top