Safe low PSI for stockers UPDATED 6/30: Pics Added

hurl · **Posted:** Wed Jun 23, 2010 1:33 pm

I'm heading down to OBX in a few days. I've got my tow hooks, hitch and snatch strap and can't wait to hit the beach. Checked it out last year but didn't have the recovery points so didn't really do much. This year I hope to do much more. :JEEPIN:

What I am wondering is what everyone thinks is a "safe" psi when airing down the stock Goodyear Wranglers? Don't want a flat on the beach

The mrs would never let me hear the end of that.

I see posts with PSI's ranging from low teens to mid 20's but No one mentioned if they were the crappy wranglers. An yeah I'm getting ride of them before winter, they're just about done. Last year I think i went low 20's

Thanks!

KKeith · **Joined:** Thu Oct 09, 2008 3:06 am **Posts:** 58

I have always run 16PSI in my tires(stock or other wise) for off road activities. Never had problems.

Jeepin_it_real · **Posted:** Fri Jun 25, 2010 9:31 am

they say a little less than max PSI is safe

KKeith · **Joined:** Thu Oct 09, 2008 3:06 am **Posts:** 58

Jeepin_it_real wrote:

they say a little less than max PSI is safe

Jeep_it_real who exactly is "They".

A little less than Max PSI will do very little. Any tire will have no problems at that pressure during 4wd activities, as road speed increases so must the pressure. For high speed gravel road your tires would be at around 25-28 PSI. Some of our Outback roads here in Australia are made of what is called Gibber, basically roundish stones with some sharp point's on them about 2-4" in diameter. If you ran tires at "a little less than Max PSI" you could not carry enough tires for the trip. In this country this could mean the difference between life and death.

Be very careful suggesting tire pressures to someone who is asking "what pressure should I run"? As without proper Training and Experience a lot of problems can occur.

I have been 4wd instructing for many years now and have prepared many groups for outback travel.

jimymc · **Joined:** Thu Dec 17, 2009 7:51 pm **Posts:** 248

KKeith wrote:

Jeepin_it_real wrote:

they say a little less than max PSI is safe

Jeep_it_real who exactly is "They".

A little less than Max PSI will do very little. Any tire will have no problems at that pressure during 4wd activities, as road speed increases so must the pressure. For high speed gravel road your tires would be at around 25-28 PSI. Some of our Outback roads here in Australia are made of what is called Gibber, basically roundish stones with some sharp point's on them about 2-4" in diameter. If you ran tires at "a little less than Max PSI" you could not carry enough tires for the trip. In this country this could mean the difference between life and death.

Be very careful suggesting tire pressures to someone who is asking "what pressure should I run"? As without proper Training and Experience a lot of problems can occur.

I have been 4wd instructing for many years now and have prepared many groups for outback travel.

OK... so what are your recommendations for Gibber and other off-road pursuits, Mr. Instructor? How about deep sand?

KKeith · **Joined:** Thu Oct 09, 2008 3:06 am **Posts:** 58

jimymc wrote:

KKeith wrote:

Jeepin_it_real wrote:

they say a little less than max PSI is safe

Jeep_it_real who exactly is "They".

A little less than Max PSI will do very little. Any tire will have no problems at that pressure during 4wd activities, as road speed increases so must the pressure. For high speed gravel road your tires would be at around 25-28 PSI. Some of our Outback roads here in Australia are made of what is called Gibber, basically roundish stones with some sharp point's on them about 2-4" in diameter. If you ran tires at "a little less than Max PSI" you could not carry enough tires for the trip. In this country this could mean the difference between life and death.

Be very careful suggesting tire pressures to someone who is asking "what pressure should I run"? As without proper Training and Experience a lot of problems can occur.

I have been 4wd instructing for many years now and have prepared many groups for outback travel.

OK... so what are your recommendations for Gibber and other off-road pursuits, Mr. Instructor? How about deep sand?

For deep sand start at about 18 PSI and see how it goes, if it's tough going lower a little more. Tires withhout bead locks could go as low as 12PSI however more care will be required when turning and keep your speed down. See with our modern more powerful vehicles alot of people negect there tire pressures particulary when sand driving. If the going gets tough they just put there foot down more. This creates a situation where the engine builds up heat very quickly, so quick in extreme cases with CRD engines that it is common for a radiator to burst the tanks of both ends of the core. A hard working engine and low air flow due to low speed is a recipe for disaster. The easier you can make it on your engine the better, so low your tire pressures to suit the situation. You will know the correct pressures for your vehicle with a little bit of trial and error. When the pressures are right the vehicle will feel almost un-stoppable and very comfortable. Try it yourself on a gravel road you know well, first drive the road at road pressures then drive the same road with 4-5 PSI out of your tires. It will be heaps more comfortable, nicer on the vehicle. But remember you can not drive at highway speeds with reduced pressures. The side walls will over heat and the tire will blow out.

Check out a typical Australian Gibber road on you tube here: http://www.youtube.com/watch?v=-DBn1xITltc

tjkj2002 · **Posted:** Fri Jun 25, 2010 11:27 pm

With stock tires I wouldn't go below 20psi due to only having a 1 ply sidewall.The lower you go and more of the sidewall is driven on,not good mix with 1 ply sidewall tires.

Now with a better LT tire in a load range C/D/E with at least 2 ply sidewalls your safe to lower psi's depending on the tires width and rim width.With stock sized tires(but in LT rating) and on stock rims about 15-16 would be the lowest I'd go.You want the narrowest rim possible and you can go lower without beadlocks.With beadlocks psi's of 3-6 are the norm if you have a light rig.

jimymc · **Joined:** Thu Dec 17, 2009 7:51 pm **Posts:** 248

Thanks guys good, direct, technical, usable advice.

hurl · **Posted:** Sat Jun 26, 2010 9:12 am

Thanks all. Exactly what i needed.

Jeepin_it_real · **Posted:** Sat Jun 26, 2010 6:47 pm

let me correct my post... a little less then half of the max PSI

stumpjumper_09 · **Posted:** Sat Jun 26, 2010 8:36 pm

tjkj2002 wrote:

With stock tires I wouldn't go below 20psi due to only having a 1 ply sidewall.The lower you go and more of the sidewall is driven on,not good mix with 1 ply sidewall tires.

Now with a better LT tire in a load range C/D/E with at least 2 ply sidewalls your safe to lower psi's depending on the tires width and rim width.With stock sized tires(but in LT rating) and on stock rims about 15-16 would be the lowest I'd go.You want the narrowest rim possible and you can go lower without beadlocks.With beadlocks psi's of 3-6 are the norm if you have a light rig.

X100

GeekyJeep · **Posted:** Sat Jun 26, 2010 9:31 pm

ok silly question.
how do i know what rating my tire is and what ply it has?

Dayton Timberline AT II

stumpjumper_09 · **Posted:** Sat Jun 26, 2010 9:35 pm

Is there a "P" or a "LT" before the tire size?

Example
LT 245/75/16

"P" is only 1 ply and "LT" is 2 ply or more

GeekyJeep · **Posted:** Sat Jun 26, 2010 9:40 pm

Interesting.
it sais P ( tire size here)
but at closer inspection in really small text i found this:
Sidewall:2 ply polyester

hurl · **Posted:** Mon Jun 28, 2010 5:59 pm

GeekyJeep wrote:

Interesting.
it sais P ( tire size here)
but at closer inspection in really small text i found this:
Sidewall:2 ply polyester

same thing on mine

GeekyJeep · **Posted:** Mon Jun 28, 2010 6:09 pm

im ging to take that as... better than a normal all terrain tire.. but not as good as a true E rated LT tire..

stumpjumper_09 · **Posted:** Mon Jun 28, 2010 9:21 pm

was hoping Troy would chime in there.............. :ALONE:

jimymc · **Joined:** Thu Dec 17, 2009 7:51 pm **Posts:** 248

My P rated tires also have 2 ply sidewalls as well. That seems to bring a new twist to the recommendations. Does the ply of the sidewall now determine the safe pressure to air down to? :?:

Does it change what has been said previously above? :?:

Hmmmm.

tjkj2002 · **Posted:** Mon Jun 28, 2010 11:22 pm

jimymc wrote:

My P rated tires also have 2 ply sidewalls as well. That seems to bring a new twist to the recommendations. Does the ply of the sidewall now determine the safe pressure to air down to? :?:

Does it change what has been said previously above? :?:

Hmmmm.

Not really.

Tires have a all elusive "ply rating" that has really nothing to do with how many actual plys they have.A "P" rated tire is a 4 ply rated tire,standard load and rather on the weak side as far as sidewalls."C" LT tires are 6 ply rated tires,far stronger sidewalls but with about the same load capacity as a "P" rated tire."D" LT tires are 8 ply rated,and "E" LT tires are 10 ply rated tires.

Offroad specific tires(not AT's) will have the tread extend down the sidewalls for extra protection(and traction) when aired down.

Now take my 35x13.50x15 Toyo Open Country MT's.................

-LT tire
-Load range "C"
-6 ply rated
-3 ply sidewalls(polyester)
-3 polyester plys,2 nylon plys,and 2 steel belts in the tread

Toyo's

And the General Grabber AT which is a "P" rated tire.

Big difference in the sidewall area.

Then you got the awesome Maxxis competition tires.

hurl · **Posted:** Wed Jun 30, 2010 9:44 pm

I just wanted to say thamks again.

I to the 4x4 area yesterday and got around without any problems. i went down to 23psi to stay above 20 and leave a few pounds room in case i got stuck. Such a variety of sand from sugar to hard packed but i never felt that i was going to get stuck. Nervous a few times in deep sand but not worried.

Only issue was almost crapping my pants when i saw my first horses since they ran towards me and i hadn't yet realized how melow they are. (first one's is a video of this, may need to click. hope it works) if not ... http://s618.photobucket.com/albums/tt27 ... D00013.mp4

and some other pics

Safe low PSI for stockers UPDATED 6/30: Pics Added

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