Rocket City Rock Crawlers Homepage
Forum Home Forum Home > General > General 4x4 Discussion
  New Posts New Posts RSS Feed - How to find proper tire pressure
  FAQ FAQ  Forum Search   Events   Register Register  Login Login

How to find proper tire pressure

 Post Reply Post Reply
Author
Message
Bruce View Drop Down
RCRC Club Visitor
RCRC Club Visitor


Joined: 11 January 2020
Location: Madison, AL
Status: Offline
Points: 2
Post Options Post Options   Thanks (0) Thanks(0)   Quote Bruce Quote  Post ReplyReply Direct Link To This Post Topic: How to find proper tire pressure
    Posted: 24 May 2020 at 3:18pm

Sorry that I haven't been able to make any of the events. I had some family issues come up and then someone started a pandemic just to keep me from having fun.


I do have a nube question though. Since the tires for my Jeep are after market, the contact patch is bigger than the stock tires. How can I figure out the proper pressure for them? I'm talking about highway pressure and not on the trail.


Thanks,

Bruce

Back to Top
98TJ View Drop Down
RCRC Club Member
RCRC Club Member
Avatar

Joined: 10 May 2005
Location: Maysville, Madison County
Status: Offline
Points: 7009
Post Options Post Options   Thanks (0) Thanks(0)   Quote 98TJ Quote  Post ReplyReply Direct Link To This Post Posted: 24 May 2020 at 5:47pm
There are different ways to do it, but what I have found with my TJ and JK is: lower pressure drives better, but higher pressure gives better fuel mileage and tire wear.

What brand / size tires do you have?
1998 TJ 4.0 5spd Atlas 36" Swampers RE4.5 ARB's 44/44
Back to Top
alabamatoy View Drop Down
Admin Group
Admin Group
Avatar
I dont work here anymore...

Joined: 16 February 2004
Location: Madison, Al
Status: Offline
Points: 8984
Post Options Post Options   Thanks (0) Thanks(0)   Quote alabamatoy Quote  Post ReplyReply Direct Link To This Post Posted: 25 May 2020 at 8:57am
Read the sidewall of the tire, it will have max load at pressure cold.  I have always tried to run about 5% less than max cold pressure. 

Too much pressure (as long as its under max cold pressure) wont hurt the tire unless you have wide tires on narrow rims, then it will wear the center of the tread faster than the outside since the tread will be somewhat bowed due to the beads being closer together than they should be.

In my experience at the racetrack, my Porsche tires would grow about 9PSI from cold to when they just came off the track after a run, which is almost 20%.  So the "PSI Cold" ratings on the sidewalls take that temp growth due to heat into account.  This temp growth is substantially reduced with N2 instead of air.  I think CO2 temp growth is better than air, but not better than N2.
"If you didnt buy your 1st gen 4Runner new, then YOU are a newbie!!"

BRC Life Member
Back to Top
Recon View Drop Down
RCRC Club Member
RCRC Club Member
Avatar

Joined: 10 April 2017
Location: New Market
Status: Offline
Points: 400
Post Options Post Options   Thanks (0) Thanks(0)   Quote Recon Quote  Post ReplyReply Direct Link To This Post Posted: 27 May 2020 at 6:05am
Hello Bruce, 
    You will find that this will have nearly as many answers such as what oil is best, and which tires are your favorite. Generally the sticker inside your door will get you close. Now, since you have a much larger contact patch over stock generally you can go lower and still be safe with the tire. When I had 35x12.50s on an 8 inch wide wheel on my old XJ I ran 25psi on the road. My opinion with your 2 door wrangler would be set the front at 32 and the rear at 28. That might set off your TPMS though. Its just something you will have to play with.  Remember that tire flex will warm them on the road and raise the pressure like alabamatoy said.
1988 YJ Wrangler
2020 Gladiator (wifes)
Back to Top
CJ7OX View Drop Down
RCRC Club Member
RCRC Club Member
Avatar

Joined: 17 February 2004
Location: United States
Status: Offline
Points: 1850
Post Options Post Options   Thanks (0) Thanks(0)   Quote CJ7OX Quote  Post ReplyReply Direct Link To This Post Posted: 27 May 2020 at 3:22pm
In my CJ, I typically run 35psi on the road, and my tires are 36x13.50s. I would imagine you would be fine anywhere from 25-40, just choose whichever feels best to you, and allows even treadwear.
~Sean
Some people spend an entire lifetime wondering if they made a difference in the world. But the U.S. ARMED FORCES don't have that problem. -Reagan

MOLON LABE
85ish CJ-7/06 CTD

Back to Top
 Post Reply Post Reply
  Share Topic   

Forum Jump Forum Permissions View Drop Down

Forum Software by Web Wiz Forums® version 12.01
Copyright ©2001-2018 Web Wiz Ltd.

This page was generated in 0.078 seconds.