Air pressure

[Marc]

To all of you that are running full size trucks with either a FWC or ATC I was wondering what Air Pressure you are using on and off road, as well as what size tires ? Your comments are appreciated.

Marc

 

[lqhikers]

my 2 cents worth of hot air

Marc,I feel that you need to explore the basic's first.Type of tire(off road/comb)street,snow,etc.Load rating,type of driving (most freeway/gravel roads) I say this for the years i lived in Idaho 80%of my driving was dirt/gravel,you get my drift.This being said as i have said in the past depending on the use at the moment the tire pressure should be adjusted to conditions.This is the biggest thing i see people not doing.(you know "we are only going a few miles down this rocky road to camp")this is when you have problems,then if you do lower pressure you get back on road and put off adding air till you get gas etc.I say this as you asked about air pressure with fwc/atc on truck,which says you are using as most of us do drive to area,explore,drive back home.So in my opinion a good on board air system is the best answer to air pressure question!There have been times that within 1/2 mile I have lowered pressure from 20 psi to 5-7 psi to get out of soft,soft sand then back up to 20 psi to reach road then up to 32 psi to head home,A real pain but easier than changing tire or trying to get unstuck!Hope this adds to your confusion!
Drive slow and enjoy "its the journey"
Les Lqhikers

 

[SunMan]

Marc,
On my Tundra I'm running 35psi up front and 40psi in the rear with camper and most of my gear on a daily basis. When fully loaded (Water tank/boards on roof/extra firewood/cooler maxed with ice) I'll run ~45psi in the rear. When going offroad (Baja style), I start my dropping 10 psi all around and go from there depending on conditions. Deep sand would be a whole different story. On my recent overnighter on average dirt roads, I didn't change a thing. Hope that helps.

Oh, I'm running BFG All Terrrain KO's 265/75/16 (the stock size) and carry a Q-Maxx compressor from Costco, it works great.

 

[the fisherman]

More Hot Air

Lqhikers= Good advice

 

[Marc]

Thanks for the reply guys. I'm running 285/75/18 Toyo AT's, about a 34" tire. I keep my rig preatty much loaded up all the time with the exception of water and perishables, This way I can cut out preatty quickly. I too carry an on board compressor and tire recovery kit. Off road air down to about 20 psi and on road to 65 up front and 60 in the rear. I was just curious to what others were doing.

Marc

 

[simimike]

I'm running 60 PSI on the highway and off road. On my Dodge 2500 I have BFGoodrich A/T LT 265 70R17's. These are the OEM tires.

My "off road" has been forest service roads so the 60 PSI hasn't been a issue. After I get a compressor I'll take the road less traveled.

Cheers,

Mike

 

[craig333]

I'm very familiar with the airing down thing. My Jeep I'll take down to 8psi for the rocks, even less for sand and snow.

My truck however I'm more leary of airing down. Its heavy. And, unless I'm towning the jeep, I have no way to air back up. So far the dirt roads I've been on it just hasn't seemed necessary yet.

I'll tell a little story here. I'm in my old (1976) dodge 4x4 flat towing my Jeep on the way to four wheel drive run in central California. Looking at the maps I thought I'd found a shortcut beyond what directions the run people had given.

Its march and of course its raining. Rivers of water are coming across this little two lane road. At the end of the road is this spooky little town with chain link all around and signs saying do not stop. No problem I dont want to stop. A mile from this town the road turns to dirt and theres a big sign saying "four wheel drive recommended, impassable in wet weather" or something like that.

Its raining harder and I'm going uphill. Finally lose traction and can't move anymore. I can't take the Jeep off the truck because I'm solo and its now a two person job because of the slope. I can hear the night run on the cb (did I mention it was darker than heck?) but I can't raise anyone.

Ah well, I figure i might as well try airing down. I don't really expect it to work. Takes me an hour as I have to climb back in the cab and warm up after each tire.

Put the truck in gear and hallelujah it starts to move. Some fairly deep water crossings and an hour later I pull into camp around one in the morning. Phew.

The next day I find out the road I got stuck on was actually part of the Jeep run.

 

[kcowyo]

My truck isn't full size, but my tires are -

285/75/16 BFG AT KO's - I run them at 35 psi in the front, 40 psi in the rear on the road. On long dirt tracks like in Death Valley or in Utah, I air down to 16 psi. It really helps improve the ride by cushioning harsh washboard impacts.

I carry a Superflow MV-50 air compressor for airing back up and Staun Tire Deflators to air down.

The Stauns are ok, but for less money I've seen and I like the ARB EZ Tire Deflator.

 

[EdoHart]

I run 60 front and 60-65 rear for on-road with my 285/70R17 (non-stock size) tires. I used the "business card" method to determine these numbers. Basically, that involves playing with the pressure until you can just barely fit a business card under the edge of the tire.

I really need to take the time to use the "chalk" method in which you make a chalk line across the entire width of the tire, then drive it in a straight line until you have left 2-4 chalk lines on the pavement and adjust the tire pressure until the tire leaves a consistently wide chalk mark on the pavement.

Off-road, I find that I can go from swimming through sand to crossing rocky dry washes or wet streams and I would rather not have a low tire pressure on rocks. Also the weight of the truck with the camper usually gives me enough traction to comfortably traverse the loose stuff. I haven't crossed any sand dunes or deep snow with the new truck (yet) but I have driven through deep mud and very mild snow (a couple of inches) and my on road pressure has worked well. With that said, one reason I went to bigger tires was to get more ground clearance, the other was to get a larger contact patch, especially when I do have to air down. The thing about a diesel truck is that it weighs so much that, in my opinion, it's better to press through the loose stuff on top and grip something solid deeper down or, have very large tires to support the weight so you can float on top of the loose stuff.

 

[pvstoy]

I
I really need to take the time to use the "chalk" method in which you make a chalk line across the entire width of the tire, then drive it in a straight line until you have left 2-4 chalk lines on the pavement and adjust the tire pressure until the tire leaves a consistently wide chalk mark on the pavement.
.


Hi Ed,

A easy way to do the chalk is to draw a line across all the tires, not very heavy line then drive straight for about 100 feet or so. Get out and see if the chalk is worn off even. Chalk left on the outside means too much air, take some out and drive it again with a new line.

Remember to do it when the tires are cold and your truck, camper is either loaded or 3/4 loaded.

 

[EdoHart]

Thanks Patrick

I've read about it, but never did it, so I think I had some of the details wrong. Besides my Scout and a VW rabbit, this is the first vehicle that I've put over size tires on. The Scout is very forgiving, but it weighs half as much as this truck. The Rabbit was when I was a kid and didn't know any better.