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-   -   Tire Pressure 30" (http://www.wranglerforum.com/f282/tire-pressure-30-a-124499.html)

2003 wrangler 11-25-2011 08:37 PM

Tire Pressure 30"
 
I was wondering, what would be the ideal tire pressure to maximize fuel economy and to maximize tire life for a 30" yokahama geolandar at-s tire. The sidewall of the tire says that the max load is at 50 psi and I have been keeping it around that 50 psi mark. Is this ok or am I doing something wrong? I just worry about it because I feel like my rear tires are wearing more than my front tires and I only have about 3k miles since I got my jeep. Thanks in advance for all replys!!

TnDz TJ 11-25-2011 11:29 PM

For one.... That is max psi. I run 30-35 psi on my 31's. The more psi , the better mpg you may get and a harsher ride than with a lower psi like 25-28.

Tmstar05 11-25-2011 11:42 PM

Holy cow r u nuts? Lol yea 50 is the max plus your chances of burning rubber are superb lol which wears out your tires real quick even when you come to a complete stop and you make a turn your tire will spin and in no time your tires will be bald especially the back ones first. I run 25psi on my 33's but stay in between 1500-2000 rpm's. And I rotate them every 6000 miles.

cork1958 11-26-2011 05:35 AM

Yeah,
32-35psi on my 31's also.

Defiance03Sahara 11-26-2011 05:48 AM

Look at the sticker on the inside of the drivers door, That is the manufacturers specified cold psi for that vehicle. my 2003 sahara with 30x9.5 is 29 psi.

doclouie 11-26-2011 07:14 AM

30 psi on 31s.

TnDz TJ 11-26-2011 08:13 AM

lower your psi down to 30-35 and you will think you are in a Cadillac LOL!!! The wear is also going to show more on the rear since you have a better tendency to 'slip' with such a high psi. Rotate your tires at every oil change ( every 3000 miles for me) and keep them uniformly even.

2003 wrangler 11-26-2011 03:08 PM

Since I read all of the posts, I have lowered my psi in all of my tires to 32psi. Is that good? Thanks for all of the replys it is greatly appreciated. I guess since this is my first jeep, I didnt realize that that was so bad, but im glad I asked i learned something new today! Thanks.

freeskier 11-26-2011 03:15 PM

10 Attachment(s)
Quote:

Originally Posted by Defiance03Sahara (Post 1772880)
Look at the sticker on the inside of the drivers door, That is the manufacturers specified cold psi for that vehicle. my 2003 sahara with 30x9.5 is 29 psi.

Manufacturer specs go out the window when you deviate from stock tire size.

InvertChaos 11-26-2011 03:21 PM

Quote:

Originally Posted by freeskier

Manufacturer specs go out the window when you deviate from stock tire size.

30x9.5 is about stock tire size iirc

Rinkers Ranch 12-04-2011 09:33 AM

How low should I set tire pressure when going off road? 30 X 9.5 Not rock crawling, just trail and maybe mud.

2001 Wrangler Sport, stock suspension.

Atthehop 12-04-2011 10:24 AM

I ran 26 in my 30's and 28 in my 31's. Got over 75k on 30's and 19-20 mpg highway. These are BFG AT's which have stiff sidewalls.

Jerry Bransford 12-04-2011 11:46 AM

Quote:

Originally Posted by Rinkers Ranch (Post 1797426)
How low should I set tire pressure when going off road? 30 X 9.5 Not rock crawling, just trail and maybe mud.

2001 Wrangler Sport, stock suspension.

You can safely air them down to 12-13 psi. Any higher than that and you're really not airing down.

I once had a new Rubicon owner and his wife (both new to offroading) in my group doing a moderately difficult trail. He and his wife were getting progressively angrier saying we misled them on the trail's difficulty, that it was way more difficult than they were led to believe it would be. They were having trouble and their tires were spinning where I didn't think they should be spinning so I asked what pressure he had lowered his tire pressure to. He very testily said they were aired "way down" and that he wasn't going any lower. 30 minutes later he was by then holding the group up and his wife was pissed at the world and all of us for "misleading" them so badly. I pushed back hard on the tire pressure issue and pushed for what pressure his tires were at when he snapped back '20'. After a few minutes of discussion, I told him either he or I was going to take his tire pressure down to 12 psi. He was unbelievably angry by this time so I just started airing his tires down when he took over. Once he got his tires to 12 psi, he had no more problems on the trail and the guy and his wife finally started having a little fun with their new Rubicon.

Moral of the story... don't be afraid to air your tires down enough. This wasn't directed at you Rinkers Ranch, this was just a quick story to illustrate the importance of airing down 'enough'. :)

Rinkers Ranch 12-04-2011 03:19 PM

Thanks Jerry, that is exactly the information I needed. I looked over this site for a # but the only thing I found about off road tire pressure was 'air them down' before getting on the trail. I have no problem with the 12 -13 psi range. I didn't want to drop the pressure so low as to pop the bead off the wheel.

Also on the highway pressure; I was told by my friend who owns a small tire shop, the factory spec is set more to ride quality than tire wear or handeling. He said to determin the best wear tire pressure was to set the pressure between factory pressrue and max tire pressure. His formula is to take the Max pressure on the tire, subtract the factory spec. pressure, take half of the difference and add it to the factory spec. pressure and this is the best pressure for tire wear. So I run my Jeep tires at 41psi. 50psi - 32psi = 18psi /2 = 9psi + 32psi = 41psi. This has given me great tire wear on the Jeep, pick-up, and car, but at the expense of the ride quality. Just the same, I'm going to air them down, on the Jeep, to about 32psi, run them that way for a couple of weeks, and check for any change in the wear.

Thanks again, Wayne

Oh, I told you wrong about my tire size. They are 31" X 10.5" BF Goodrich M+S.

RSC17 12-04-2011 03:26 PM

Quote:

Originally Posted by Jerry Bransford (Post 1797712)
You can safely air them down to 12-13 psi. Any higher than that and you're really not airing down.

I once had a new Rubicon owner and his wife (both new to offroading) in my group doing a moderately difficult trail. He and his wife were getting progressively angrier saying we misled them on the trail's difficulty, that it was way more difficult than they were led to believe it would be. They were having trouble and their tires were spinning where I didn't think they should be spinning so I asked what pressure he had lowered his tire pressure to. He very testily said they were aired "way down" and that he wasn't going any lower. 30 minutes later he was by then holding the group up and his wife was pissed at the world and all of us for "misleading" them so badly. I pushed back hard on the tire pressure issue and pushed for what pressure his tires were at when he snapped back '20'. After a few minutes of discussion, I told him either he or I was going to take his tire pressure down to 12 psi. He was unbelievably angry by this time so I just started airing his tires down when he took over. Once he got his tires to 12 psi, he had no more problems on the trail and the guy and his wife finally started having a little fun with their new Rubicon.

Moral of the story... don't be afraid to air your tires down enough. This wasn't directed at you Rinkers Ranch, this was just a quick story to illustrate the importance of airing down 'enough'. :)

I know you are referring to the specific question but let me add that the width of your wheel is a factor on how much you can air down. Stock Jeep wheels and wheels up to 8" are safe running that low (12psi). A 9" wheel is probably going to be OK as well. When you get to 10" wide wheels, the possibility of popping a bead is very high at such low pressures. This, of course, pertains to a standard wheel with no beadlock. This is exactly why I'm switching out my 10" wheels for 8". I wouldn't even have 10" wheels if I hadn't gotten them for free. :thumb:

Jerry Bransford 12-04-2011 04:42 PM

Quote:

Originally Posted by Rinkers Ranch (Post 1798172)
Thanks Jerry, that is exactly the information I needed. I looked over this site for a # but the only thing I found about off road tire pressure was 'air them down' before getting on the trail. I have no problem with the 12 -13 psi range. I didn't want to drop the pressure so low as to pop the bead off the wheel.

Also on the highway pressure; I was told by my friend who owns a small tire shop, the factory spec is set more to ride quality than tire wear or handeling. He said to determin the best wear tire pressure was to set the pressure between factory pressrue and max tire pressure. His formula is to take the Max pressure on the tire, subtract the factory spec. pressure, take half of the difference and add it to the factory spec. pressure and this is the best pressure for tire wear. So I run my Jeep tires at 41psi. 50psi - 32psi = 18psi /2 = 9psi + 32psi = 41psi. This has given me great tire wear on the Jeep, pick-up, and car, but at the expense of the ride quality. Just the same, I'm going to air them down, on the Jeep, to about 32psi, run them that way for a couple of weeks, and check for any change in the wear.

Thanks again, Wayne

Oh, I told you wrong about my tire size. They are 31" X 10.5" BF Goodrich M+S.

41 psi is simply too high for a Load Range C 31" tire supporting a vehicle with the weight of a TJ. The factory's recommended air pressure hasn't been about ride quality in many years, it is now higher for better mpg so they can up their fleet (CAFE) mpg averages to meet the ever increasing EPA's regulations.

Rinkers Ranch 12-05-2011 05:22 AM

Thanks for the quick reply. I'm going to lower the air pressure today. I understand your comment about tire pressure and ride quality. Yes, my friend and I both learned our tech stuff in an earlier time, and have not kept up with some of the changing technology as I should have. 42 years with Caterpillar (tractor division) taught me just how fast technology changes, and just keeping up was a full time job. Now that I'm retired I don't keep up with things as well as I use to.

Thanks again for helping and old man keep up, Wayne

shanes04wrangler 08-27-2012 11:15 PM

on my 04 tj it says 33psi inside the door but i have my 30x9.5 at 30psi. I just fig its better for wear and comfort and mpg dont matter its a jeep.


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