offroad tire pressure?

[jenny]

Can the folks who do serious offroading suggest from their experience what is the best tire pressure to run at?  I have 35 MTR's..not sure if this makes a difference or not?

[HeadHunter]

I run my 31's @ 15psi with out bead locks, but with bead locks you can run as low as 6-3psi.

gotta make sure you have a reliable way to refill before you hit the pavement again.

[01sahara]

Can the folks who do serious offroading suggest from their experience what is the best tire pressure to run at?  I have 35 MTR's..not sure if this makes a difference or not?

I generaly run my tires at 8-12 PSI off road.

[FiEND]

i ran my rubicons with 33" at 10lbs.  nathan did the same, same rims with 31" mtr's when were out together.

they are 8" aluminum rims.  tires do matter.  sidewall strength matters the most.  blowing a bead is not a huge deal, puncturing a sidewall is the suck.

i'd start at 15 and see how they are.

[hps4evr]

i have 33" mtr's on 8" wide rims. ive had them down to 8psi without blowing a bead. but ive never had them that low and driving fast into a hard turn. they have excellent traction at the 10psi mark. and yes, a good air pump is mandatory.

[rangerdanger]

I run 33" TSL's at 12 psi on 8" rims with no problems.

[JohnB]

A good way to determine the safe amount of deflation for your setup, if you have tubeless tires, is to measure the sidewall height versus pressure.  Park on a flat and level surface and inflate to the maximum shown on the tire sidewall.  This will be the 100% height.  Now deflate and keep track of the sidewall height.  Make sure the amount of load within the vehicle is typical of what you would normally carry.

85% is usually a safe all around height.  A rule of thumb that I’ve heard before for sand driving is 75% and is a reasonable minimum choice for off road winter driving in our area.  For general off roading, 85% makes a safe point and very rarely have I found a bead popping at this level. You can run lower, but more care should be exercised when turning and when using power as you go lower and lower.

[BlackYJ]

It has a lot to do with the tire and rim you rare using.  I used to run my 31" MTRs at about 14 with a 8" rim, but now with my 33" SSRs I have had them down to about 8 psi but typically run about 11-12 psi.  The SSRs have a much thicker sidewall.  If you are running a wide or very narrow rim you chance of popping a bead get bigger.

The biggest difference you will notice is going from like 30 psi down to about 15 psi and after 15 you don't gain that much more footprint. 

[Bnine]

It really depends on the tires.

Our toyo's dont really work until they are under 6lbs, but they are a stiff tire.

Soft tires like boggers, bfg's, and 15" mtrs will flex at higher pressures.

I wouldnt go below 12psi without beadlocks as a general rule. Although I've popped them at higher pressure, 12 is fairly consistent.

[RedApe]

I've run the following:

33x12.5x15 Yokohama Mud Diggers @ 6Lbs      (Toyota)
33x12.5x15 Big O XT @10Lbs                                  (Toyota)
33x12.5x15 Swampers @ 8Lbs                                (Toyota)
33x12.5x15 TRXUS MT @11Lbs                              (TJ)
31x10.5x15 MT/R @11Lbs                                        (TJ)
30x9.5x15 BFG AT KO @15Lbs                                (XJ)

All of the 33's were on 8 wide...the 30 and 31 were on 7 wide.

I agree with Bnine, depends on the tires construction and compound, vehicle, terrain and driving style. 

[Slewfoot]

Hi,

I'm running BFG Mud-Terrain T/A KM2 on a stock '06 Rubicon.  Tire size is 245/75R16 and I believe the rims are 8 inches wide.  The tires have 3-ply sidewalls and BFG brags about the sidewalls being one of the toughest and puncture/tear resistant out there.

From what I read earlier in this thread, it looks like I'd be OK to run them at 15 psi.  At the last Open Run (my first), folks suggested 20 psi, and hinted that going lower is risky.  From what I read here, it looks like the risk isn't much higher at 15 psi than at 20.

Does 15 psi sound reasonable for my current setup?

[specialk]

You'll be okay going down to 15 psi.   I ran that with the same size Goodyears with no problems.

[cLAY]

Typically I run 12psi in my 36" and 37" IROKs, radial and bias ply. The radials definitely bulge more than bias ply did. I live in Cochrane so I don't worry too much about running that short distance on the highway from Waiporous to here.

In Moab I was running the bias ply IROKs at 8psi and they were conforming quite nicely to the rocks. However the trials down there start on the edge of town so not much highway driving to speak of.

I'm running an 8" wide rim with either a 12.5" wide tire(radial) or 13.5(bias ply). The recommended rim width for those tires is 10" but I prefer the 8" as I think the narrower rim is less likely to pop a bead. Has worked good so far.

[Vinman]

I ran my 35" MTR's on 8" rims (non beadlock) at 8 psi when wheeling, never once had a bead pop. Once you start running single digit air pressure you'll discover 2 things, first is how much difference in traction a 1 psi drop makes when you're running single digits and second, why did I ever wheel with double digit tire pressure?

I once "rolled" a 35" BFG AT off the rim enough to lose all the air but not un-seat it. When I checked the rest of the tires one was at 4 psi and still on the rim. At that time all the tires leaked when aired down due to the bead mounted balancing weights.

Bottom line, keep airing down a little at a time until you start having problems and then add a couple of psi.

Of course, like others said, an air supply is a must before hitting the highway.

Vince

[hps4evr]

seeing as how its a 245/75r16, stock size, i think going to single digit pressures could cause a tire to come off the bead much easier then a wider/taller aftermarket tire. 245's are pretty skinny so i think sticking with double digits until you upsize tires will be your best bet. 15psi would probably be a good place to start.
i wheeled with 33/1250r15's on 8.5" wide rims. had them down to 8psi and they were great. usually id just have abotu 12 up front and 8 in the rear. that set up worked well.
adjust as you go. buy a good air compressor.