PSI - How low do you go?

dieselenthusiast · **Posted:** Sat Oct 18, 2008 9:13 pm

When off-roading, is there a magic PSI number for airing down? Naturally it depends on the size of tire and the quality of the rim to hold a bead. Is there any other considerations before airing down?

corwyyn · **Posted:** Sat Oct 18, 2008 9:19 pm

For most of the wheeling I do I will go down to around 18-20psi, though I have gone as low as 15psi. I personally wouldn't go much lower than that because the last thing I want is to have to try and set a bead out on the trail (although I know it could be done if needed).

tjkj2002 · **Posted:** Sat Oct 18, 2008 9:22 pm

The wider the rim the less you can lower the psi.I run 16x7 rims with 265/75's and can airdown to 10psi with not alot of worrying about blowing a bead,I have blown beads at 12 psi before but anything less then full psi(42 for me) would have resulted in a blowout.I generally go to 15psi though,those Trxus seams to like 15psi better when beating the snot out of them.

Get these...............
http://www.high-impact.net/wheels/dot_approved_beadlocks.htm

And going down to 6psi,even 3psi,is more then okay.I only need about $2400 and I'll have me a set,in black of course :wink:

.

Inc · **Posted:** Sat Oct 18, 2008 10:24 pm

This is just my opinion from how my tires, on my KJ seem to have acted while off road. My other jeeps were all different.

I used to run 15 psi and called it good. Never had any issues really. I then started running 18 and now 20 off road. I haven't been able to tell enough difference off road to really seem worth while to air down that low though. I did notice I bottom out more off road when at 15 psi over 20 psi though. So for me, I like to keep as much ground clearance as I can and since running the tires at around 20 psi seems to be fine off road, I'm going to run them like that. If I was running 35s I'd be running the tires at 12-15 psi though. A lot of guys run their rigs at 8 psi, in fact a poll on a local forum asked this same question and 8 was far and away the mots popular answer.

mrkake · **Posted:** Sun Oct 19, 2008 2:15 am

18 - 20 for me as well. I have gone as low as 10 with my MT/R's and Moabs, but I was worried about popping a bead the whole time. I think terrain and the tire/rim set up you have may play into it as well, I just don't know how much.

Fouros · **Posted:** Sun Oct 19, 2008 6:28 am

18-20 for me sometimes if really needed 16PSI

2006 KJ · **Posted:** Sun Oct 19, 2008 11:04 am

i normally go to around 15-18... depends on the conditions i'm wheeling in. if it's REAL muddy they go to 15.. it's it's mostly rocky i'll leave it around 18

Tokyojoe · **Posted:** Sun Oct 19, 2008 2:25 pm

16-18 psi for me.

QuestMan · **Posted:** Sun Oct 19, 2008 2:47 pm

Depends: If you go to Silver Lake, in MI, the DNR won't let you go out on the dunes, until you air down to 15psi OR less. A couple of years ago, I took a tour on the dunes with a company called, Sandy Korners. You use their jeeps, and they show you what a stock wrangler can do out on the sand. They NEVER have move than 8psi in their tires.

Myself, I do pretty well in the mud with about 18 - 20 psi.

ohv_kj · **Posted:** Sun Oct 19, 2008 10:18 pm

well..depend on rim width, tire size vrs rim width, side wall of tire and weight of vehical...with my sfa i went to 15 lbs w/ 33x1250x15 MTR and 15x8 rim...it seemed to be a good mixed

but you need to go atleast under 20 to see any real affects from it...

when i had the stock rims and 265/75/16 mud kings w/ 2ply side wall...18 lbs and the tire flex really well

KJ Taz · **Posted:** Sun Oct 19, 2008 11:05 pm

12-15 is what I have been running with the MTRs. I have not popped a bead but I have spun a tire on the rim one time (edit, I think I was at 10 that day).

Joe Jeeper · **Posted:** Mon Oct 20, 2008 9:52 pm

I run 20 PSI on the trails. :wink:

RAYMAN975 · **Posted:** Mon Oct 20, 2008 10:35 pm

im running 235-85-16, on the stock 16x7 wheels. i didnt know how low i could go on these tires since they are kinda skinny for the rim? if its a skinnier tire does it have a higher chance of popping a bead? the tire place said that i wouldnt want to go any narrower of a tire with these 7" wide wheels(they werent talking about airing down, just in general)

dieselenthusiast · **Posted:** Mon Oct 20, 2008 10:51 pm

RAYMAN975 wrote:

im running 235-85-16, on the stock 16x7 wheels. i didnt know how low i could go on these tires since they are kinda skinny for the rim? if its a skinnier tire does it have a higher chance of popping a bead? the tire place said that i wouldnt want to go any narrower of a tire with these 7" wide wheels(they werent talking about airing down, just in general)

I learned the other day from TJKJ2002 that the Moabs are less likely to pop a bead (due to the design of the lip). I’m sure the size of your tire is important, but I’m going to take a guess that the design of your factory rims play an equal part. My factory tires on my KJ are 235’s on a 7” rim. I’ve never aired them down real low, nor have I put them through extreme tests, but so far I haven’t had any problems.

PSI - How low do you go?

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