Tire pressure Question

[bigdon 55]

I'm headed to Big Bend National Park after Christmas. I've run all the back roads on my Moto but not in a 4x4.
We will either be taking our Taco but probably our FJ Cruiser. Both have 285's on them.
Traction will not be an issue but would like to air down for better ride quality.

What pressure should I run for better ride but not low enough to put my sidewalls in danger?

Thanks, Don

 

[t-rex grrr]

I have 295/70 Toyo MTs on my 4runner and usually run 20 PSI on the trails. I believe I can go slightly lower, but 20 is good enough for my needs.

 

[jeep-N-montero]

15-20 will be plenty low enough for sucking up bumps but not really enough to kill mpg's.

 

[r_vdb]

20 is safe number for me on my 285's on the Tacoma or the Land cruiser with 305's.

 

[LR Max]

X whatever on 20 psi. I've used that on a few rigs over the years. Seems to help take the bump out, provide good traction, and not be a pain when airing back up.

Start with that and see how it feels.

 

[BigSwede]

20-25 is a good number. You don't want to go much below 18 with allow wheels, to protect them from damage. I like to go 25 if I will have intermittent highway miles amidst the trails, it is enough to handle okay and not hurt the tires at highway speeds.

 

[Robert Bills]

What pressure should I run for better ride but not low enough to put my sidewalls in danger?

I agree with Frenchie. 20 psi for a rig with the weight of a loaded FJ or Tacoma running 285/75R16 load range "E" tires on relatively mild terrain sounds about right as a starting point. You can air down a bit more if you need your tires to be more compliant (such as over rocks, etc.). You can air down less if you are traversing graded dirt roads or easy trails and your goal is just to reduce the tooth rattling a bit for ride comfort.

I typically air down to 18 psi for my Xterra with 265/75R16-E Cooper Discoverer ST/Maxx tires on factory wheels. When I ran 35x12.50-15 "C" rated BFG Mud Terrains with steel wheels on my CJ-7 I would air down to 16 psi and adjust down from there depending upon the trail. Trial and error will help you zero in on the appropriate tire pressure for your rig(s).

The tire pressure most appropriate for your rig depends upon the weight of your truck, your particular tires, your driving style, the particular terrain, your ability to air up without depending upon a distant gas station, etc. Recommendations to run a particular air pressure or anecdotal responses such as "I run X psi" are relatively meaningless without some reference to these factors.

 

[155mm]

My stock pressure is 44psi. I'll go down to 30-35 depending on the road conditions. I'd rather be driving than airing up and down all the time and I wouldn't want to drive on the highway below 30psi. If it's just sand I'd start at 20psi and then air down further only if required.

 

[Longrange308]

30-35psi is what I typically run until I need the extra traction in really soft stuff..

 

[Jessica1987]

I keep my tires at 30 psi :smiley_drive:

 

[Happy Joe]

The recommended tire pressures on the side walls is for max load of the tires (you should be aware where you vehicle fits with respect to this load rating, IMO.
I establish the "best" tire pressure using the chalk test for common, personal, vehicle loadings, each time that I replace the tires/change brand/type.
I typically drive highway and street in the 24 to 26 psi range.
For significant off road travel I reduce pressure to what the trail/terrain seems to require, most don't;
I don't see significant, off road, traction improvement until around 12-15 psi. and have gone much lower; with increasing risk of unseating the tire bead.

Enjoy!

 

[IdaSHO]

Simply tossing out PSI recommendations is pretty silly.


To run at the correct tire pressure you need to consult a load chart for said tire, and/or do a chalk test.

 

[Texan1983]

Simply tossing out PSI recommendations is pretty silly.


To run at the correct tire pressure you need to consult a load chart for said tire, and/or do a chalk test.

except that doesn't work off road.

I usually try a few different pressures based on load and terrain. but for the most part I go as low as I can without risking the tire coming off the wheel. in my heavy truck ive gone to 12-15lbs with no issues on steel and alloy wheels. I think you guys are sacrificing a lot of comfort and traction because of a little more time airing up. also if there is a little pavement section I keep the speed below 50 and don't bother airing up. anything longer that 30 miles or so I will go ahead and air up some though.

18psi seems to be my starting point fyi...

 

[IdaSHO]

except that doesn't work off road.

Sure it does.



Every tire is different.

Every vehicle weighs a bit different.

18PSI for one tire and rig will NOT equate the same to the next rig.


Speed is one of the variables involved in the charts.
Load charts provide a starting point.

Reverse engineering it from the charts and experimentation is the only way to find the right PSI.

 

[IdaSHO]

This is a pretty good article on tires and load ratings

http://www.fourwheeler.com/how-to/wheels-tires/1407-understanding-tire-load-ratings/

Clipped from the article, as I mentioned...

Off-Road PSI

Proper on-road pressure serves as a starting point for safe off-road airing down.