Hi. I'm asking what tire pressures would be okay for my to run off road? The truck: '91 Pickup 22re 5-speed. My tires: 32x11.50x15 Goodyear MTR on 15x9 inch aluminum rims, no beadlocks. The terrain: sand, small stones, water. I aired them down to 5 psi today in the shop at work just to see how they would be like...first of all, hard to steer, even with power steering! When I kicked the tires, they felt like they were going to fall off the bead...scary. But I can see the added traction of airing them down. So can I run them at 5 to 10 psi off road without losing a bead? 'Cause I have no source of airing them up again if they lose a bead...

 

curious my self.

 

Start your research here: http://tinyurl.com/2xkquw

Pressure will vary from rig to rig, driver to driver and terrain to terrain. There's no magic answer. But 5-10 is getting pretty low on that combination.

 

Lowest I ever ran in my T100 with 31's is 15 psi I wont go any lower and its all I needed.

 

Good info in that link Rob.

He mentions snow too, and I have read in the past tall cookie cutter type tires work best, but he says the opposite.
The wider the better for snow.

 

I would say, if you want to get low, i.e. 8-12psi, get 7" or 8" wide rims for your 11.50 wide tire.
Otherwise, running a rim only 2-inches more narrow than your tire, I wouldn't go any lower than 16psi.
Having a narrow rim will hold your beads so tight that it is almost like having beadlocks, imo. I have heard/read from a few sources that for off-road use, run a rim 3- to 4-inches more narrow than the tire width. For on-road use, 2- to 1.5-inches more narrow.

 

Thanks for the information, guys. Anyone else with suggestions?

 

if you have no way to air them back up you probably shouldn't go as low as 5-10psi on trails. but if youre like me and don't care, just bring spares. I bring a small air compressor with me. I use it as just an air tank to be able to drive on roads after wheeling, but should power be available I can air up a lot faster and higher.

I run 32x11.5s on my DD on 15x8s and they do fine at 12psi. Never popped off yet thankfully.. but I did fill the bead with a lot of dirt.

 

hodgepodge has it right.

For reference, i know a guy who is beadlocked and runs at about 8. If you aren't, I'd say safe bet, with a narrower rim, would be 10-12. Lower if you are risky, higher with the wide rim.

 

I agree... narrow rims help keep the beads on, plus they are easier to reseat if you do pop one off.
As far as how low you can go, many factors can play a part. Terrain, vehicle weight, tire type (radial/bias ply), sidewall stiffness (# of plys), rim width, and rim type (some have taller beads, usually factory alloys). I've seen a lightweight yota p/u run on as little as 3-4 psi on sand without incident. I have personally run low enough with a 6500lb 3/4 ton chevy I had, to pinch the sidewall and cut it- the other danger of low psi. I doubt that will be an issue with any yota though. I've also popped a bead off with that truck- and I was really asking for it, it took a lot, donuts in the mud and hit a bump.
Reseating a bead isn't that hard especially if it's only the outer. Just jack up the truck and pull the tire outwards while inflating.

I'm curious if anyone has tried gluing their beads with weatherstrip adhesive, been thinking about trying that, kinda like a cheap beadlock substitute.

And don't air down without a pump, they're only $20 at Pep Boys!

 

on mine, specs in sig, i never go lower than 12. i usually run from 15-20, depending on conditions.

 

me and all my friends go the magic 10. None of us have ever had a problem. weve done it in jeeps,prerunner trucks and toyota 4x4s. I used to run like 15 and i would get axle hop going up this one sand hill and when i finally went to 10 i made it up first try.

 

the tires i used to use wheeling were 33x12.50x15s on 10inch centerlines. i have had the fronts as low as 2 psi and the rear at 1 psi. This is not a regular thing just have had them there before. Me and my friends usually run at 7 front 5 rear. We do alot of snow wheeling and you got to be low.

I have never popped a bead. Came close one time but wouldnt have been a popped bead it would have just let all the air out.. I got a piece of ice jammed in the bead had to break out a road flare and heat up the rim till the ice melted. I was worried about the aluminum rims and the road flare but hey it worked and resealed with 1psi.

 

I usually go 15 PSI with my MTR's and if I need the traction I go 12 in the rear. I have 7 inch wide rims so I don't worry about the bead like you do. My wheeling is sand/rocks also.

 

something that no one has mentioned, or i missed it, is for those who DD thier rigs, popping a bead isnt the only thing to be concerned about. When you lower your tire pressure you also increase the risk of the tire spinning on the rim, thus changing your wheel balance. Its always a good idea for those who DD thier rigs to use chalk and mark a line that crosses rim and tire to see if you've spun it if you air down real low.

back to topic, id say around 15 safely for your combo... I run between 7 and 15 with 33x12.50 on an 8" rim, and could probably go less if needed. But, like many have said, it will depend on setup, driver, and conditions.

 

For 32's, try starting at 10psi.
If that works ok for a few trips you can drop it another pound and try that.
If that works ok, try 8psi.
Basically start at 10psi and work your way down until you start loosing beads.
Go back up another pound or so and you're there.

Be sure to put a register mark on your tire and rim, for reference, for each wheel.
What'll happen is that you'll start turning the tire on the rim thus your wheel balance will be off.





Fred

 

My personal experience with too wide a rim for a tire is this:

I had 33x12.50's that I routinely went down to 12 PSI on. 15x8 rims. It was fine.

Then i went to a 9.50, same rims, and the first time out i went down to 12, and promptly rolled the tire off the bead. Same at 14. So I went to 17, and I have no issues.

 

if you dont want to lose your bead... next time you have your tires rotated by a shop, have them put bead sealer on the bead of all tires. its not as strong as beadlocks, but it holds. i use it myself. i still wouldnt go down past maybe 12 or 14 psi for fear of damaging the sidewall. a good thing to invest in is a CHEETAH bead seater. take along the cheetah and some compressed air. if you lose a bead, fill up the cheetah, put it against the rim pointing into the bead, and let her rip. watch out though, she jumps. if you know how to use it, it will work every time.

 

So I went out today. I aired them down to 12 psi. I some pretty gruesome (well, to me anyway) lines up a half-sand covered hill, and never lost a bead, although a Cherokee with 33's and lockers front and rear made it look too easy. I had to take the lines usually a few times to make it, but made it (no lockers!). I'm guessing I could have went down to 10 psi, even possibly 8, but as this was my first time airing down my tires, I did not want to risk it. But the aired down tires made a HUGE difference in grip, especially off-road.

 

I've seen people make these things out of an old propane tank and a 1" ball valve, plus a piece of pipe. Boom!

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