I know it's a good idea to lower air pressure in tires for snow....gives you a better contact patch. But what about light snow-covered roads. I just got home from driving in about 2" on the road and my BFG's were all over the place with about 18psi front/rear. (The snow was pretty wet and slick.)
I had to "seriously" feather the gas to keep from spinning the rears. I don't know, maybe it's the RV performance cam that's causing too much torque at low RPMs. I'm sure driving style and "type of snow" have a lot to do with it, as well as tire brand/quality. My BFG A/T's have about half-tread and I usually drive like a granny. <img src="/forums/images/graemlins/lol.gif" alt="" />

What air pressure do you guys run for light snow on roads? My 4Runner is pretty light in rear....no rear seats, light-weight bumper and no tools.

Thanks,
shaggy <img src="/forums/images/graemlins/notooth.gif" alt="" />

I generally run about 28-30lbs. Normal air pressure, but not all the way up to 35lbs. I think 18 is a little low for just a couple of inches of snow. You may be getting some roll in the sidewall that is throwing your truck around and not helping the problem. I would add at least a couple hundred pounds of weight in the back to balance the rig and help with traction. 2 or 3 tubes of sand generally do it for me. You should be able to get the tubes of sand from either Home Depot or Lowes and they weigh about 70lbs each. <img src="/forums/images/graemlins/cheers.gif" alt="" /> Dan...

How wide are your tires? Wider tires make you float, so it doesn't help. I'm running stock tires on 32 psi and run at 55 without any weight in back. 18 psi is almost sand/rock crawling pressure; the sidewalls flex a little more.

I run real low (single digit) pressures in DEEP snow to get up on top of it, but for a couple of inches on the road I run normal pressures. If you are travelling at any significant rate of speed then you are better off cutting through the snow than being on top of it. Go easy on the throttle too and keep the revs as low as possible without lugging the motor.

Tires are 30x9.5 and that should be OK. I'll have to air them back up and add some weight in the back. Thanks to all for the advice.
Gonna be going offroad tomorrow and hitting some snow-trails. Let you guys know how it goes.
And yes, I agree that ya gotta keep them revs low...I just end up lugging it which isn't good for the squirrel....hopefully we'll have more snow here on the front range this year so I can get some practice. <img src="/forums/images/graemlins/lol.gif" alt="" />

shaggy <img src="/forums/images/graemlins/smile.gif" alt="" />

So many variables to consider when tire inflation pressure is concerned...

Long story short, if you are on pavement and expect that your tires can reach it, then it is preferable to do so rather than float on top of the snow, which means running with higher pressures so your tires can push the snow away. If, on the other hand, the snow is too deep to cut through or you are not on pavement, then a lower pressure that allows you to stay on top of the snow is best. Around where I live, there is often mud underneath the snow(lots of springs pushing water up even when most stuff is frozen).

If you want to get into the physics of it, consider why studded tires work well on ice: The studs are small points on the contact patch that create very high pressures, much higher than the rubber that surrounds them. The higher pressures at those points allows the stud to 'dig' into the surface giving you better traction. If you've ever seen the tires that are used on rally cars for winter/ice races, you'd see that they are very skinny. The contact patch is smaller and therefore psi is higher. Of course, when the terrain changes from glare ice to fluffy powder, the high pressure idea doesn't work very well at all cuz' ya just sink in the snow.

Just something to keep in mind: when your tire is inflated to 20 psi and that tire is carring 1000lbs., your contact patch will be 50 square inches, regardless of the size of the tire. This is why bigger tires allow for lower pressures and therefore better flotation. The same principle works for load carrying ability; in general, if you want to carry more weight, you need either more pressure or a larger tire. Another option, of course, is to use more tires to handle the extra weight, which is why we see dually pickups.

enough rambling... hope this helps clear things up.
Happy wheeling.

You might consider siping the center tread blocks. I did that with my old 33x9.50 BFG MTs and found it made a huge difference in snow traction. Before siping, it was very easy to break them loose and afterwards, it took some work to do the same:

Tire Siping

Well, snow hit us pretty hard and got about a foot in the high country.

Ran 30psi and didn't have too much of a problem on the road. It was when the old '82 Chevy conversion van passed me running street tires that was embarrassing. <img src="/forums/images/graemlins/lol.gif" alt="" /> My truck just couldn't handle the hills ad was breaking loose and losing power (8K elevation)....unfortunately there was no place to slow and put the rig in 4HI prior to getting to those hills...oh well.

When I hit the trails things were OK. The heavier trucks seemed to have very little problems with steering in and out of the snow ruts. My rig had such a lightweight feel to it...it bounced around like a pinball....it was fun though. <img src="/forums/images/graemlins/notooth.gif" alt="" /> It was around 2degrees and the snow was hard.
I think I'll look into the siping idea. I agree that there are a lot of variables. That's why I have a garage full of bicycle mountain bike tires that I used for racing....a pair for any conditions. Too bad truck tires ain't cheap...I'd have a garage full of them too.LOL

shaggy

Here in the Sierras when on the highway I run my 33x12.50 BFG AT KO's at 35 psi(my normal street pressure), and they haven't missed a beat as long as I am light on the throttle and brakes, same for the ice. My truck is weighs quite a bit more than stock, and the weight is distributed almost 50/50 front/rear.

Sipe the tread like Roger said, and put a couple 100 lbs of sand in the back for better traction and weight balance.

In most snow conditions on the road, street tires or all-terrains will do better than MTs (at least unsiped ones), Those other tires have sipes in their read pattern and have a many more tread edges than the big monolithic MT tread blocks. Also, good time to just lock the front hubs and when you need 4H, just pull the stick back while you are driving and keep going. No need to slow down or even press the clutch in. As long as the rear end is not spinning/sliding, you can pop from 2H to 4H any time you want as long as the hubs are locked.