Enthusiast I
- 404
- First Name
- Robert
- Last Name
- Burton
- Member #
29695
Hello,
When airing down, what pressure do you all run?
Thanks,
Rob
When airing down, what pressure do you all run?
Thanks,
Rob
Tire Pressure
- Thread starter raburton12
- Start date
Trail Blazer II
- 6,140
- First Name
- Shaun
- Last Name
- Johannes
- Member #
15310
- Ham/GMRS Callsign
- KE8TDZ
Depends for me. I run skinny 33s so I'll break down below. Once I go back to a wider tire I'll be able to come back down more.
Road: 39 PSI
Gravel: 32-30 PSI
Dirt/Multi: 30-27 PSI
Rock: ~ 26 PSI
Mud/Sand: 22-20 PSI
Road: 39 PSI
Gravel: 32-30 PSI
Dirt/Multi: 30-27 PSI
Rock: ~ 26 PSI
Mud/Sand: 22-20 PSI
There are so moving pieces here, what tire, what rig, what load, what is the tire rating, where are you driving, sand, mud, rocks, washboard?
I start at 50% of my road pressure on most washboard.
I start at 50% of my road pressure on most washboard.
Pioneer II
- 6,020
- First Name
- Dustin
- Last Name
- Helms
- Member #
24720
- Ham/GMRS Callsign
- KD2UNH
- Service Branch
- USAF
I usually just go to 20psi if I am airing down. I don’t have beadlocks and I am not an extreme rock crawler or anything so I don’t want to see how low I can go. 20 is a lot smoother than 35 for sure though lol
This is a good question
In his book, Shifting into 4WD: The SUV Owner's 4WD Handbook, Harry Lewellyn instructs to lower the air pressure so the sidewall is 75% the height of the correct on-pavement air pressure. Then, record what that air pressure for future reference. I like this approach because it negates the effect of weight of the vehicle and contents which vary as well as tire size.
Trail Blazer II
- 6,140
- First Name
- Shaun
- Last Name
- Johannes
- Member #
15310
- Ham/GMRS Callsign
- KE8TDZ
Member III
So many factors , e rated thick tires on a light rig go down to 8 psi in snow , same tires on a heavy rig 15 psi . Matters so much on terrain/weight /speed of travel / tire construction. Really it’s one of those experiment things . Do a truck test and find out what your street psi is and go from there.
Edit , chalk test not truck test .
Edit , chalk test not truck test .
Last edited:
Enthusiast I
- 404
- First Name
- Robert
- Last Name
- Burton
- Member #
29695
Enthusiast I
- 404
- First Name
- Robert
- Last Name
- Burton
- Member #
29695
Trail Blazer II
- 6,140
- First Name
- Shaun
- Last Name
- Johannes
- Member #
15310
- Ham/GMRS Callsign
- KE8TDZ
No problem. Obviously like others stated your mileage will vary based on rig, tire size, tire load rating, rig weight and other factors. So I'd suggest using @terryg's suggestion until you dial in your own settings.
Pioneer II
- 6,020
- First Name
- Dustin
- Last Name
- Helms
- Member #
24720
- Ham/GMRS Callsign
- KD2UNH
- Service Branch
- USAF
Trail Blazer II
- 6,140
- First Name
- Shaun
- Last Name
- Johannes
- Member #
15310
- Ham/GMRS Callsign
- KE8TDZ
Yes chalk test is a great one. However if you don't fancy as much trial and error I'd recommend this tool. Tested the cacluation with the chalk test and came out perfect.
Tire Pressure Calculator
Easy to use tire pressure calculator. Use our tire pressure calculator to calculate the new tire pressure needed when changing tire sizes.
Pioneer II
- 6,020
- First Name
- Dustin
- Last Name
- Helms
- Member #
24720
- Ham/GMRS Callsign
- KD2UNH
- Service Branch
- USAF
Check that out! I just went outside to confirm the numbers and that thing gave me the same as the chalk test too! Gonna go do it to the wife’s truck next lol
Jeep Wrangler, 2000# trailer, I run 26psi almost everywhere, if I'll be under 30mph and thru soft sand, over boulders etc for the day, I'll drop to 15psi.
I don't do the rock crawling thing, I avoid mud, I never run thru a stream.
In winter, I chain up.
I don't do the rock crawling thing, I avoid mud, I never run thru a stream.
In winter, I chain up.
Off-Road Ranger I
- 2,865
- First Name
- Donald
- Last Name
- Diehl
- Member #
0745
- Ham/GMRS Callsign
- WRPN 506
Interesting; I attempted that method with E rated BFGs. Could never really determine 75% of what? Flat? To the OP, Our wagon, when loaded is at its GVWR 6900lbs +/- and does quite well at 20lbs, down from 36lbs in every sort of terrain one might cover. I aired down to 12lbs only once and aired back up ASAP as it was quite uncomfortable floating like that, along with the possibility of popping a bead. HAVE FUN
I usually go down to 18psi for most roads and rocks for my full sized rig but ive gone down to 10psi in snow and I dont have bead locks i have beadlooks
Member III
Trail Blazer II
- 6,140
- First Name
- Shaun
- Last Name
- Johannes
- Member #
15310
- Ham/GMRS Callsign
- KE8TDZ
I read it as 3/4 of fully inflated. Based on that mine would be ~6 3/8" compared to my 8 1/2" sidewall at full load inflation. I'll do some testing this weekend and report back on what psi that 75% sidewall comes back as.
2dr Wrangler on 35's 38psi on road, 18-20 psi off road and loaded with gear.
Influencer I
Usually 36psi on the road, but 18-24psi on the unpaved roads around here - the washboard/corrugations on most of them are bad enough to pound the heck out of your suspension if you don't drop the tire pressure. (or they get rough enough to warrant the lower pressure for traction)
