psi in tires
JK Junkie
Joined: Sep 2007
Posts: 3,306
Likes: 1
From: Long Island, NY
my .02.. start at 35-37 PSI. take childrens sidewalk chalk, make a line along the width of the tire, roll the JK a bitt.. check out the chalk if its wearing on the sides only, you have too little air, center, too much.. work with that and see what happens, If I were to guess youll end up in the high 20's..
JK Super Freak
Joined: Aug 2009
Posts: 1,255
Likes: 2
From: GRANDE PRAIRIE, AB
80 and the tire will last alot longer, will be a bit stiffer but you're in a jeep. the main reason for the high pressure is because the tire has a load rating and it can only handle this load at 80
JK Jedi Master
Joined: Jan 2008
Posts: 11,463
Likes: 165
From: Austin <--> Colorado Springs
You're suggesting actually running at 80 psi? Are you freaking kidding?
Here is the blurb from the FAQ's stickied to the top of this section. Generally a decent place to start.
Try running them at various 'lower' pressures to see what feels best, and also do the chalk test to see what pressure gives the best footprint.
I generally run my 295/75/16's around 30-32psi. My tire shop puts them back up around 45 when I take it in for rotations, and the ride gets far too stiff and flighty.
Here is the blurb from the FAQ's stickied to the top of this section. Generally a decent place to start.
Q: On the road, what PSI should I be running in my tires?
A: For optimal comfort and even tire wear. you should not run the recommended PSI listed on the sidewalls of your tires. Typically this will be way too much. On average for a 33" tire, I would recommend that you run your tires at approximately 28-30 PSI. For a 35" tire, I would recommend running approximately 26-28 PSI. For a 37" tire, I would recommend approximately 24-26 PSI.
Q: On the trail, how much should I air my tires down to?
A: Typically, I recommend that people air the tires down to about 10~15 psi.
A: For optimal comfort and even tire wear. you should not run the recommended PSI listed on the sidewalls of your tires. Typically this will be way too much. On average for a 33" tire, I would recommend that you run your tires at approximately 28-30 PSI. For a 35" tire, I would recommend running approximately 26-28 PSI. For a 37" tire, I would recommend approximately 24-26 PSI.
Q: On the trail, how much should I air my tires down to?
A: Typically, I recommend that people air the tires down to about 10~15 psi.
I generally run my 295/75/16's around 30-32psi. My tire shop puts them back up around 45 when I take it in for rotations, and the ride gets far too stiff and flighty.
Last edited by nthinuf; Sep 18, 2009 at 07:52 AM.
JK Enthusiast
Joined: Jan 2009
Posts: 310
Likes: 0
From: Windsor, Ontario
i run 305/70/16, i felt them get low, and saw my mileage go way down. i checked them and i was at 30. i say low to mid 40's. i've heard (never done) that you can used a temp gun to check the heat on your tires after driving a bit.if its hotter on the outsides, put more air, center take some out, and only one side mean you out of alignment. sounds like a good idea to me!
JK Enthusiast
Joined: May 2009
Posts: 446
Likes: 0
From: Chihuahua
Just my 0.02> I have MickeyThompson's 33's and I run them at 28 on the street and 15 on the trail...
Higher than that you are just bumping around a lot. Yes, its a jeep, but you don't want to feel like you are inside a washing machine when you drive it...
Higher than that you are just bumping around a lot. Yes, its a jeep, but you don't want to feel like you are inside a washing machine when you drive it...
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JK Jedi Master
Joined: Jan 2008
Posts: 11,463
Likes: 165
From: Austin <--> Colorado Springs
One other thing to note is that those are load range 'E' tires. Very stiff sidewalls, designed for big heavy trucks hauling big heavy loads. If you don't plan on dropping a couple tons of gravel in the back of your JK, you'd be better off going significantly lower on the psi... 
Last edited by nthinuf; Sep 18, 2009 at 12:24 PM.
Super Moderator
Joined: Sep 2007
Posts: 1,750
Likes: 88
From: Arizona
You didn't say what JK you have, but the curb weight of the 2-door is 3,849 lbs. One tire at 80 PSI is enough to support the whole Jeep, so here are my helpful suggestions:
- Sell three and run one at 80 PSI.
- Run 4 at 80 PSI and haul 12,000 lbs of cargo.
- Lower the pressure to about 20 PSI and do the chalk test to find the best running pressure.