I just bought bfg muds size 30x9.5R15 -What tire pressure is reccomended for on the road use?
Thanks!

 

Ive always ran 33 or 34 for road use then drop them down to 22 or so for wheeling.. what did the tire shop put in them?

 

I would say about 30 psi all around personally.

 

what about 31x10.5x15 procomp xterrain? the sidewall said a max of 50psi, should i run close to 40-45?

 

I think the recommended pressure in the doorframe is 28-30psi, not sure how much tirechoice changes this

 

40-45 is too much for your truck.. the tire max is 50, that means fully loaded when compared to a certain equation is how much it can support, @ 50 psi i believe its something like that tire can support 5500 pounds alone... for it to matter, your truck would need t oweigh 20000 pounds fully loaded and your tire pressure is perfect.... but your truck weights nowhere near that....

 

The tire shop put about 37psi but it seems too much-they filled them with nitrogen.

 

Greetings,
It should indicate in the sidewall what the pressure should be. It should say "COLD TIRE PRESSURE" someplace along the sidewall near the rim.
Filling them with nitrogen is very good since nitrogen does not permeate the rubber as air does. This keeps your tire pressure regulated for a longer period of time.

 

about 37PSI into mines. Since i mostly just commute to school i want max fuel economy.

 

i run 30 on the street, and 10-8 on the trail, but ive got 35's

 

so what should i inflate mine to? for 31x10.5x15?

 

I have 32x11.5r15 and run 40

works well for me. I say 35-40. try it out and see how it rides.

 

As others have said, what is printed on the sidewall "does matter", and the pressure you run should be calculated based on that.

On my sidewall it states that my tire is rated at a max of 50psi at 2250lbs cold. So if I take 2250lbs, divided by 50psi, my tire will handle 45lbs of weight for each pound of air. Now, the GVWR of my truck is 5350lbs, divided by 4, each tire carries 1337lbs. (1337/45=29.71psi). I run 30psi, and I can't fit a business card under any of my contact patch, meaning my tires will wear evenly.

If you stray from this calculation, you risk wearing out the center of the tread first, with too much pressure, or the outside of the tread with too little pressure.

 

I forgot to mention that Air also has water vapor and Nitrogen does not. This also effects the tire pressure as the air heats up.

 

Roger Brown has an excellent write-up about this on his site.

 

Anywhere between 32-40 will be fine for most LT and P tires.