Deep Snow PSI? Cooper Discoverer ATP 265 75 16

Hey TW,

Stock steel wheels and Discoverer ATP's, usually run 18-20 psi for mud/rock/dirt off road. How much lower would be safe for deep snow wheeling?

 

What are you saying by deep? For best traction a snow tire wants to cut down through the snow to find something hard to grip so higher pressure is good. if we are talking about deeper than the frame lower pressures will work like a snow shoe.

 

I've never aired down in winter.

 

Sorry, I should have clarified I am talking about Pacific North West snow. It gets super deep here and as you mentioned above airing down helps prevent digging yourself in.

More specifically Im just wondering what is the lowest reasonable pressure I can air down to with stock steel wheels and P rated tires.

 

I'm interested in this too, I live in Oregon and have had terrible traction in deep snow.

 

You can try lower pressure, like down to 10 PSI if you want. Just be easy about making turns. Too much side pressure can break a bead at very low pressures. The problem is, you will start plowing snow sooner and that will stop you. Stock tires do not provide enough surface area to float the truck at any pressure. There are two strategies that have worked for me. Tall skinny tires with good chains go like hell, and are my favorite. Tall fat tires can be aired way down and float the truck pretty well in powdery snow. They are hell on ice. The snow in the PNW is usually wet and icey. I used to run tall skinny tires with machine siping (Les Schwab) at around 20 PSI with chains in reserve.

 

Not stock sizes, but tall'n'skinny LT235/85R16's, I've aired the fronts down to 12Psi in deep snow. We drove into an area on top of very crusty late season snow on a cool morning, thinking because the road was shaded we'd drive out the same way after an hour or two. Not to be - we sank into 20+ inches very quickly, Even my brother in his Toyota pickup on 33's aired down all around with ARB locker was floundering badly. In the end, I chained up the rear, and aired the front way down to help it float, and took lots of runs at it to break trail and get out about 3 kilometers. Lesson learned. So yes, 10 or 12 will work, but don't steer while stopped.

 

I've done the same thing before. It doesn't take much of a temp change to alter snow conditions.

OP, you should be fine at 15 with P rated tires. The real tell is how much the tire squishes as you air down. Don't let the rim of the wheel get too close to the ground - you can lose a bead or shred the tire. With my E rated tires, 10 psi still has tons of sidewall.

 

Funny, looking at that picture shows how much sun that road ACTUALLY got - LOL. We thought we were going to be there 'till she froze up again that night, which would have been bad as we both had our young boys along.

 

Good feedback. It sounds like the idea of 10-15 psi front tires (minding the sidewall) with chains in rear is a wining combo, from what I'm reading here.

For those of you who chain up the rear, do you leave it at full pressure?

I've got a good set of chains http://www.tirechain.com/square_alloy_cross_chain.htm which comes with cams, and these metal spring adjusters http://www.tirechain.com/adjusters-light-truck.htm . I just got 'em this year and haven't mock fitted them up yet but looks like I'll be able to get them really tight onto the tire, which I hear can be an issue if chaining on deflated tires.

 

When using chains, you want the tires aired up usually - I'm sure there are times when they work better aired down. Sometimes in the spring, I'm in snow 3 feet deep and digging down to the ground would be a disaster. I generally run at 15 psi if I think there will be stretched where I can grab a couple gears and cover some ground. If I know it's gonna be a crawl fest, I go straight to 10 psi. I haven't tried lower yet, but haven't felt the need to really. The truck goes where I tell it to.

 

Bah - Those aren't chains. These are chains.



For what it's worth, I leave the tires aired up when I run these U-bars.

Also..

That was good advice. Airing down and driving straight on easy terrain is one thing. Airing down and doing technical steep angled rock work is another. Just try and remember that there's less pressure holding your tire on the bead and maybe bring an air compressor and a piece of 4x4 or can of starting fluid to reseat the tire on the bead if needed.

As always.. go have fun and take pictures of your tits.

 

Hi @'14RC, I used to have P-rated tires on my regular cab. Here they are at 15 PSI and they don't even look deflated. You're probably fine going down to 12 or 10 PSI.

 

Well you've got me there! Those are gnarly chains.
I've been running with the MasterFlow MF-1050 compressor for about 7 months and it's been one of the best buys I've made. I should practice re-seating a bead in the driveway though.

Here's one from two weeks ago!

 

I wouldn't go and break the beads on your tires just to practice resetting them. Just watch a few youtube videos and do a little research on how to reseat the bead and wait until game time to give it a shot.

Nice truck. The young fella in me loves regular cabs.