Airing down your tires

[teebes]

Just thought I'd post some recent pics of a before/after tire deflation. Remember your air compressors


Normal ~45ish psi:



Dropped about half pressure for this trail, ~20psi

[HARDTRAILZ]

I have not aired down my current tires yet, but we used to always run 15 psi offroad. Any reason you choose 20 over 15 or lower? Seems like with all the rocks out there you would go as low as possible.

[Trail X]

I used to think the same thing... but depending on your terrain, a lower psi does not necessarily mean better. I was on a trail in PA where I had aired down due to a bit of rock crawling... but later on the same trail I was pummeling my frame and rear swaybar because the truck would deform the tires too much after coming down off rocks. I stopped, aired up to about 25 psi, and didn't encounter any more problems, and never required more traction.

I find one of the biggest benefits of airing down is ride comfort, especially when driving higher speeds over rough or washboard roads. I find that to be beneficiary much more often than having more traction, though, admittedly I don't rock crawl much.

[The Roadie]

Agreed. With us it's a constant tradeoff of ground clearance versus traction, with stuff like the Rubicon demanding the best of both. Airbags in the rear springs help a lot, since if you're higher inthe rear, you tend to get UNjammed as you travel forward, as long as you've picked the best line and are dragging a rock on the frame rail if you have to drag it at all.

So get a gas tank skid plate, already. I got mine.....

[HARDTRAILZ]

Ahh..Good point.

Clearance over traction. Makes some sense, and made me think that in some cases the extra traction will be thwarted by the dragging and rubbing of the under carriage on rocks.

Good things to keep in mind, but I generally go to the same areas and 15 worked, but make try some other pressures and see what difference it makes. It will be real intereting to see if more or less air is better when the snow is on the trail.

[teebes]

~20ish for normal trails. The same day I went dropped further to around 12-15 when I started tackling some dunes (~200 ft high, ~30 deg incline).


All depends on the trail, IMO.

[cbbryan]

I thought if you let too much out you could have the will spin inside the tire? So what is a safe bet to find the happy medium of airing down to get more traction and not less?

[Trail X]

You do run the risk of spinning a bead, but that is rare. You'd have to either be extremely low on pressure (5 psi) or have a ton of torque.

The other worry is rolling a bead, or unseating a bead when the tire is under high lateral forces. I beleive that is more of a real worry for us. And if you are really worried about that, you can get an internal bead lock. But again, that worry is for high speed cornering or low speed off-camber crawling at very low psi (10psi or so).

Optimum PSI? Play with it some, but the sweet spot (in my opinion) is somewhere between 18 and 28 psi, varying on your terrain.

[HARDTRAILZ]

I do have a question for yall.

What psi do run on the road with your larger/MT/AT tires? I run 32 as that is close to the factory 30/35 psi on the door listing and the tread seems to wear smooth and even. The tires say max of 65 psi, but I have always thought and read to keep with the trucks rating for correct performance. I have no need for 65 psi, but I would up the rear psi a bit if fully loading the truck.

[Gordinho80]

I'm running my 255/75-17 BFG MTs at 44psi on regular basis.

[HARDTRAILZ]

I need to really just get out some chalk and see how they are wearing.

[janesy86]

On a daily basis I run approx. 40psi all around.. Seem to be wearing even and rides great. Offroad depends on the trails, but usually air down to 20-25psi.

[irishboy02]

BFG m/t km2's

Rated for 80psi

On road-60psi
Weekend trips- 30psi (see wharton thread, lots of sand, mud, hills, few rocks)

Yea, it sounds really high, but it still rides great...

[Philberto]

On my 265/75/16 Discoverer ST's... max pressure 55, running pressure: 47

I run the pressure that gives me the optimal tread contact patch on highway. I allow a few psi for heating during high-speed driving (freeway).

[Excell]

James mentioned using a bead lock wheel as a potential solution to popping a bead or spinning a tire. In that vein, what about wheel screws like folks run on drag racing wheels? You'll lose air over time with them, but in my drag racing experience properly applied rubber sealant (RTV) could bring the pressure loss to a pound or two over a week or longer - and that is probably acceptable for most people. Seems like screws would be a cost effective way to reduce those risks?

Hopefully this is not a dumb question.

[Trail X]

Honestly, there's no real reason for a TB to require a bead lock (or tire screws) as long as the tire is properly fitted to the rim size, and tire pressures are kept above 15 or so.

[The Roadie]

If I can climb 40 degree sandstone in Moab aired down to 18, then traction on regular trails isn't the ultimate limiting factor. It's ground clearance and/or articulation. Trails that demand 10-12 PSI to climb are going to find another way to deny us.

[foosh]

For anything that would require us to air don to 15, we wouldn't have enough clearance for...

[janesy86]

Clearance for me has been my enemy.. so airing down too low wouldn't do much help and I've had enough traction so far on the trails/hills I have encountered.

[teebes]

There are plenty of opportunities for more traction, better gearing, etc. Just remember to use your techniques when you need 'em