psi for 35 inch tires - JeepForum.com
Search  
Sign Up   Today's Posts
User: Pass: Remember?
Advertise Here
Jeep Home Jeep Forum Jeep Classifieds Jeep Registry JeepSpace Jeep Reviews Jeep Gallery Jeep Clubs Jeep Groups Jeep Videos Jeep Events Jeep Articles
Go Back JeepForum.com > Models > Jeep Wrangler Forums > TJ Wrangler Technical Forum > psi for 35 inch tires

Oconee Off-Road Now Offering Zone Off-Road Products!!!RIGID LED Light Blowout Sale - All Sizes, All Series, all USA Standard Chromoly Front Axle Shaft Kits with Dana 30 4

Reply
Unread 06-25-2010, 10:39 PM   #1
inglisleslie
Registered User
2000 TJ Wrangler 
 
Join Date: Jul 2009
Location: St. Petersburg, FL
Posts: 1,455
psi for 35 inch tires

What do you guys run in your 35 inch tires on the road...28-32psi? I am about to get 35/12.5/15 and do not trust any tire shop. Whats your opinion for on road DD driving for a good balancing. Also how often do you rotate your tires...5k?

inglisleslie is offline   Reply With Quote
Unread 06-25-2010, 10:44 PM   #2
Benderff
Registered User
2006 TJ Wrangler 
 
Join Date: Apr 2007
Location: , Pacific NorthWest
Posts: 5,125
Here is some good info thanks to google.
So, answering the question of what is the "correct" tire pressure is not that easy. There are several DIY tests that you can try:
1. The "Business Card Test": On a smooth, hard surface, try inserting a business card between the tire and the pavement. If it goes in less than about 3mm-1/8", the the tire may be under-inflated, if it goes in more than about 6mm-1/4", it may be overinflated.
2. The "Chalk Line Test": Draw a heavy chalk line across all the tread faces. drive slowly forward in a straight line for a few revolutions of the tire. Get out and observe the wear pattern of the chalk. If it has worn away evenly, then the inflation is correct. If either the edge or center of the line is worn first, then the tire is under or over inflated, respectively.
3. The "Water Puddle Test": Similar to test #2, but drive through a puddle of water in a straight line, then get out and observe the wet tire tracks and see if the wet imprint is even, especially as the track starts to dry out after a few revolutions.
4. Heat is the #1 enemy of high-speed tires. The flexing of the tire's sidewalls as the tire rolls under load is the source of the heat. Higher inflation pressures mean less flexing of the sidewall and therefore less heat. Another test for proper inflation pressure is to measure the tire pressure when cold then again after 15 minutes at highway speed. If the pressure rise due to the temperature rise is more than about 3 psi, then the tire may be under-inflated


From here; Technical Information: Wheels and Tires


__________________
Benderff is offline   Reply With Quote
Unread 06-25-2010, 11:18 PM   #3
Tom Hartz
Registered User
1997 TJ Wrangler 
 
Join Date: Oct 2005
Location: Santa Clarita, Ca.
Posts: 433
I go by the Chalk test. I have the old BFG Muds they are just over 2 years old with 30,000 plus miles and are 1/2 worn. I have been doing 5 tire rotations every other service (that is 6000 miles) and run 25 psi in all of them.

Tom
Tom Hartz is offline   Reply With Quote
Unread 06-25-2010, 11:26 PM   #4
inglisleslie
Registered User
2000 TJ Wrangler 
 
Join Date: Jul 2009
Location: St. Petersburg, FL
Posts: 1,455
thanks a bunch guys...great guidelines!
inglisleslie is offline   Reply With Quote
Unread 06-25-2010, 11:33 PM   #5
BYuen
Registered User
2001 TJ Wrangler 
 
Join Date: Jun 2007
Location: , Arkansas
Posts: 4,636
I've found 28psi runs great for my heavier set TJ. I rotate my MTRs every 3,000-4,000 miles.

And I'm with ya about not trusting some shops. Once they inflated my tires to 40 psi and the MAX cold psi is 35... Another time I went to a different shop, they tried to convince me I needed to run 35psi in my tires and no less due to safety Stock tire size psi on the door sticker isn't even 35 psi.
BYuen is offline   Reply With Quote
Unread 06-26-2010, 12:54 AM   #6
BlueFlame
Registered User
2003 TJ Wrangler 
 
Join Date: Mar 2006
Location: Oregon USA
Posts: 8,403
Quote:
Originally Posted by Benderff View Post
Here is some good info thanks to google.
So, answering the question of what is the "correct" tire pressure is not that easy. There are several DIY tests that you can try:
1. The "Business Card Test": On a smooth, hard surface, try inserting a business card between the tire and the pavement. If it goes in less than about 3mm-1/8", the the tire may be under-inflated, if it goes in more than about 6mm-1/4", it may be overinflated.
2. The "Chalk Line Test": Draw a heavy chalk line across all the tread faces. drive slowly forward in a straight line for a few revolutions of the tire. Get out and observe the wear pattern of the chalk. If it has worn away evenly, then the inflation is correct. If either the edge or center of the line is worn first, then the tire is under or over inflated, respectively.
3. The "Water Puddle Test": Similar to test #2, but drive through a puddle of water in a straight line, then get out and observe the wet tire tracks and see if the wet imprint is even, especially as the track starts to dry out after a few revolutions.
4. Heat is the #1 enemy of high-speed tires. The flexing of the tire's sidewalls as the tire rolls under load is the source of the heat. Higher inflation pressures mean less flexing of the sidewall and therefore less heat. Another test for proper inflation pressure is to measure the tire pressure when cold then again after 15 minutes at highway speed. If the pressure rise due to the temperature rise is more than about 3 psi, then the tire may be under-inflated


From here; Technical Information: Wheels and Tires


Those really only work for 'normal' sized tires. Try to get a 35 to wear evenly across the entire face and you'll be down around 10psi...

I have found over many years and many tires that 28 psi works best. Less will yield better tread life but cost more $ in fuel. More just wears out the tires and doesn't increase fuel mileage much.
BlueFlame is offline   Reply With Quote
Unread 06-26-2010, 07:28 AM   #7
xjfever
Web Wheeler
 
xjfever's Avatar
1995 XJ Cherokee 
 
Join Date: Feb 2008
Location: north Ga.
Posts: 14,207
I run 26 psi in mine.
__________________
  1. '95 XJ country edition, 4" coils/3/4" spacers, HD leafs with extra main added in, Ironman adjustable control arms, rough country shackles, aussie locker, JK rubicon shocks, 35" mudder's, soft 8's, cobra cb
  2. Sold'99 WJ limited, 4.7L, 3" IRO lift. Bilstein shocks, JK rubicon wheels, 255/70/17's, carolina driveshaft, IRO adjustable control arms, IRO adjustable A-arm
  3. Sold '00 TJ, 4" lift, rusty's adjustable control arms, skyjacker shocks, rock krawler adj. trac-bar,rugged ridge SYE and RE driveshaft, soft 8's, 35" mud king xt's,XJ HP D30 w/aussie locker, 4:88 yukon gears, hella 500's, rock crusher diff covers
4. 04 Dodge ram 1500 quadcab, yes, it has a hemi.
5. '08 BMW X3, Mods in progress.
xjfever is offline   Reply With Quote
Unread 06-26-2010, 07:40 AM   #8
tulman22
Member
 
tulman22's Avatar
2005 TJ Wrangler 
 
Join Date: Jun 2008
Location: SE Atl, Ga
Posts: 474
Very interesting thoughts and views. Been curious also.
__________________
US Navy "SPOOK" RETIRED
Impact Orange member # 39
tulman22 is offline   Reply With Quote
Unread 06-26-2010, 07:55 AM   #9
robncar
We Got The Cup, AGAIN!!!
 
robncar's Avatar
2005 TJ Wrangler 
 
Join Date: Nov 2005
Location: La Verne, CA
Posts: 8,304
We run 24psi on the street. We've also performed an MPG test with pressures from 20 to 40. The tire pressure did not seem to have an effect on MPG, a heavy brick is a heavy brick.
robncar is offline   Reply With Quote
Reply

Tags
tire , psi
Thread Tools


Suggested Threads





Jeep, Wrangler, Cherokee, Grand Cherokee, and other models are copyrighted and trademarked to Jeep/Chrysler Corporation. JeepForum.com is not in any way associated with Jeep or the Chrysler Corp.