what should they be at for driving on the street. the guys at 4wheelparts put mine to 45 when they installed them but they say max load 50. i thought that was too close considering ive been getting those kicks in the sidewall from goin over speedbumps. ive got them at 40 now
i have pro comp mud terrains 32x11.5xr15

I run mine at around 38 psi when I'm on the roads and drop down to 12 - 15 psi on the trails depending on the terrain.

I have mine at about 30-35 psi
on the trails drop it down to 15-20 psi

with my 33x12.5x15 I run 35 road and 20 trail

I run 30 on road, 15 off road.

hmm i was told from a tire guy that u should go -10psi from your max on what your tire says, that'd be about 50 psi for me.

that guy is an idiot. thats why tires have a max psi rating on it hence not goin over that psi lol. also causing overinflation and wearing the center tread out rapidly

sigh

All the psi others are running means nothing...as they do not have the same tires you have.

Different tires have different constructions, and different load capacities, and different max psi ratings, etc.

Example, for the same size, one tire might support 2200 lb at a max of 40 psi, and another might support 3600 lb at 80 psi.

A TYPICAL starting point is to take the weight of the truck (GVWR) and as ~ 70% of that weight can be transferred to one axle by braking, acceleration, etc...figure out what 70% of the truck's weight is equal to.

So, if your truck weighs about 5,000 lb...70% of that is 3,500 lb on that one axle.

Divide by the two tires per axle, and you need the tires to support ~ 1,750 lb each.

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If tire 1 supports 2,200 at 40 psi, it would need ROUGHLY 32 psi to support 1,750 lb.

(Its NOT linear, but its close enough to ball park)

If tire 2 supports 3,600 lb at 80 psi, it would need roughly 39 psi to support 1,750 lb.

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Add to that the side wall construction, stiffness, and so forth, and some tires produce their maximum contact patch at vastly different psi.

Example - My BFG AT ko's are rarely aired down below ~ 16 psi, as the sidewalls are too bulged below that, and no additional traction is gained....but my Interco LTB's can be aired down to single digits, but the super thick bias ply sidewall rubber is still holding the tire's contact patch intact.

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So - LOOK at your sidewall codes, read the MAX PSI and MAX LOAD that goes with that psi.

Guess what your truck weighs/go to a truck stop scale, etc.

Figure out roughly what makes sense for street use.

Do a chalk test...

Rub chalk on the tread face....drive over a contrasting road section (White chalk/blacktop, etc...) and LOOK at the pattern.

If the chalk came off the middle of the tread more than the edges, you're over inflated, and need a lower psi.

If the chalk came off of the outer tread areas more than the middle, you're under inflated, and need a higher psi.

Adjust until its evenly worn.

:D

For OFF Road, just air down until you have a sidewall bulge, and, watching the PATCH....stop airing down as the patch stops GROWING. (The patch is the TREAD area touching the ground as you air down.

:D

Ignore rules of thumb with no basis, like ANY reference to things like "Just go 10 psi less than the max on the sidewall", as only idiots say stuff like that....as that would mean one tire 1 would be under-inflated at 30 psi, and tire 2 would be WAAAY over inflated at 70 psi, etc.

I’m much too lazy to air up the proper way that TJ described (he almost lost me after the first paragraph of his post).
I fill my BFG 33-12.5-15s to 38psi, make pretty sure that my truck is properly alined and then drive it. If it feels too bouncy I take some air out. If it feels too squashy I add some. After a few hundred miles, if I care to look past the cuts in the sidewall and chunks missing in the tread to see how they are wearing I might adjust but, for the most part, I adjust for my comfort and not to increase the wear on my MTs. At 45psi I’d be bouncing all over the place! I’m at 35psi right now on the Brooklyn streets. Don’t get me wrong, I want my tires to last a bit but lets be honest, they’re Mud Terrains that I beat the crap out of every chance I get.

When I go off road, rocks and/or dirt, I go down to 20-18psi. If I find myself slipping on the rocks I then take it down to 15, if still not grabbing then maybe 10. On the beach I go right down to 10.

I’ll say again, TJ’s way is the proper way, my way works for me.

i'm at 30 highway and 30 Off road. I blew a sideway at 20 PSI so i don't even bother airin down anymore.

I'm at 45 psi on my km2 for highway, usually air down to 20 psi offroad

i'm at 30 highway and 30 Off road. I blew a sideway at 20 PSI so i don't even bother airin down anymore.


30 psi on those rocks @ Rausch??? WOW!

Example, for the same size, one tire might support 2200 lb at a max of 40 psi, and another might support 3600 lb at 80 psi.

Deja vu! thats my tires youre talking about.... although, its much more fun to be there in person talking about this with flaming batteries. :anbeten-big: