Air down or not?

[Sal-XK]

well if you have Mt's or AT's something other then street tires they are actually made to be aired down. Thats were the importance of how many ply's your tire's have and such. Maybe discount tires can chime in on the subject.

[Doc in AZ]

terrain, tire and rim selection will dictate the tire pressure you will run.

i am a rock crawler & i run 35 / 12.50 / 15's on a rim that is 8" wide. i typically air down to about 9psi. my buddy that runs bead lock keeps his about 3-5psi. when i had rims that were 10" wide i was having problems with "burping" air from the bead at 12 psi. IMHO a fully inflated tire is more prone to being punctured as it is not going to flex. thing of a fully inflated balloon and how easily they pop, but with it half inflated it is more yielding. for research purposes, go out to your jeep and measure the bumper height front and rear. air it down and measure again. it will be a nominal difference. a tall sidewall like i have (10") will have more flex and will have a larger difference from fully inflated to aired down. but with a larger rim size like 17" and a 32" tire (about 7") will have much less difference.

[bruijr]

IMHO a fully inflated tire is more prone to being punctured as it is not going to flex.

I fully agree on Doc's statement. I have experienced that myself a couple of years ago. We were riding a trail in Big Bend National Park (TX) which was covered with little very sharp rocks. Since I didn't air down I punctured two tires. I ended up plugging the tire with the smallest puncture with the biggest screw I could get off my Grand Cherokee (one in the rear hatch). It worked and got us of the trail to the repair shop within the park. I have to say, it was good learning experience for me. I was just starting offroading and ofcourse had no repair plugs with me and not much experience airing down tires.

For me airing down is essential for traction and preventing puncturing the tires.

[brendon]

I air down to about 25, lower if it's really muddy. My duratracs are load rated E and have very stiff sidewalls. I barely see a difference in the sidewall height taking out 20 PSI (I run on the streets at about 45psi), but the traction and ride off-road are considerably better. I too lost some chunks on Black Bear, but there were no punctures!

[Doc in AZ]

I air down to about 25, lower if it's really muddy. My duratracs are load rated E and have very stiff sidewalls. I barely see a difference in the sidewall height taking out 20 PSI (I run on the streets at about 45psi), but the traction and ride off-road are considerably better. I too lost some chunks on Black Bear, but there were no punctures!

25 psi is what i run on the street... why would you be running 45 psi on the street? just because there is a max pressure on the sidewall doesn't mean that's the recommended pressure for all vehicles. that max pressure rating is for max load capacity. i'll bet you dollars to donuts that if you run your rig across teh scale it's only about half what the max tire rating is.

on my old work truck the tires were rated at 75 psi. when i was empty i ran about 40-45 in the rear duals and about 55 up front. fully loaded GVW 14.5K lbs, i had the front at 65 and the rears at 75.

[brendon]

The max rating on my tires is 75, so even at 45 I am no where near the max. The stock recommended pressure for the Commander is 36 on the stock tires. These tires (Duratrac) recommend a normal pressure of 40 for the Commander. On the street, I run all my tires a little over the recommended pressures as my personal preference for driveability, and because I often do have a full load in the vehicle.

[Doc in AZ]

i would keep an eye on the tread wear as a good indication of proper tire inflating. an over inflated tire will wear more quickly in the center, under inflated will wear more at the edges. you can always do the chalk test to insure you are getting a good contact pattern.