Tire pressure info [Archive] - JKowners.com : Jeep Wrangler JK Forum

: Tire pressure info


TekWarren
02-20-2008, 09:11 AM
So being a new Jeep owner and haven't done much off-roading I find myself noticing things I would like to know more about. Maybe this info is already concentrated and I can be pointed in that direction but here is first question:

How to determine tire deflation in specific terrain? I know I will be wanting to run a dune ORV park this summer and that deflation is a must but I guess I don't really know how to determine how much air to let out. I realize there are several factors such as tire size, but is there some sort of chart or list of recommendations for air pressure in "X" size tires versus "X" terrain?

Thanks!

TekWarren
02-21-2008, 05:49 AM
wow, did I ask a really dumb question is this one of those questions everyone is annoyed with so no one answers :shaking:

gcg
02-22-2008, 10:37 AM
wow, did I ask a really dumb question is this one of those questions everyone is annoyed with so no one answers :shaking:
Your question is a very good one! Probably there have been no answers so far because it seems like everyone has their own ideas based on experience as much as anything.

The closest I've seen to a table is in the book "4-Wheel Freedom" by Brad DeLong. In Chapter 12 on "Soft Stuff" he describes a method to determine how much air to let out. What he says is that you do an experiment in your garage. Start with the tires at street pressure and measure the distance from the floor to the bottom of the rim. Say it's 6 inches for now. Then calculate 75% of that height, or 4.5 inches. He says that's your rough target. Now let air out until the height from the floor to the bottom of the rim is 4.5 inches and that's a good pressure to air down to.

I think that's probably a good starting point and you may want to just try it and then experiment a little. Different surfaces may benefit from different pressures, too.

I generally air down to 15 psi for most off roading situations. If I run in sand I'll go down to 10 or 12. Other folks air down quite a bit more than this. I don't have bead lockers so prefer to not air down too much for fear of losing a bead.

igofshn
02-22-2008, 10:40 AM
I personally air down to 10 or less and usually 8 or 7 I use this for all conditions, (sand, snow, rocks and mud). I believe that air pressure is your enemy. The lower the better. it also depends on the tires you run. If you run stock tires, airing down will most likely do more damage than good. I run 35's and have for that last 6 years. I have a samurai with 31's that i run about 5, although I only run 15 on the street with it.

TekWarren
02-22-2008, 01:34 PM
Good tips! In my specific setting I have the 17" stock rims and stock tires so your comment about losing beads will be taken to heart.