Less PSI in snow?

[freemantj]

I've heard of lowering tire pressure in mud and sand, but is there any benefit in snow? If so, how low?

I travel to work at 4am, usually before the roads are plowed. I'm looking for something to help, short of chains.

Thanks,
James

 

[98 Xplorer]

James,

There is an article in the Nov. issue of Peterson's 4Wheel & Offroad magazine in which they tested three different types of tires and they aired them down to different PSI's, but it seemed that were all around the 10 PSI mark. I didn't realize airing down also worked in snow until I read this article. I've driven in sand and have aired down to 10 PSI with the Crapstones and they performed well. So this Winter when the snow comes I will try airing down in it, that is if we get enough to take the Xplorer out to play in. So according to the article, yes it helps.

Alan
98 Xplorer

 

[rpenner54]

Same idea as sand. Airing down works big time. You just don't want to do it if you are going to be driving down the road though. Its generally not good for your tires. However I am not one to listen to people who tell me that and I have run at about 15-20lbs in the snow off-road and it works wonders and then proceed to drive home on the road with that presure with no probs of going 75+mph.

 

[01EB5.0]

I woulkd think in the snow airing down wouldn't hurt if you go at like 20 or so..the problem is the extra heat generated by the tire but in snow the tirew won't be allowed to heat up that much.

 

[Ru Dawg]

The problem w/driving on street w/low tire pressure is a loss of steering control. During steering movements the vehicle will sway outward the direction of turn due to the "mushy" sidewall created by low tire pressure. As far as driving on snow, I think it depends. In light snow were your tire COULD penetrate the snow and touch pavement, I think more pressure would be better to allow the tire to "cut" through the snow. If the snow is deep and/or packed down well, then lower pressure may help. Although w/a good tread pattern on your tire normal pressure may be the best to get the "cut" effect. I've done the sand thing many times. Having to drive from the beach to the house w/the pressure around 10lbs, the only probs I've seen is loss of some steering control and extra outer tread and sidewall wear. Just my .02!!!

 

[FlyAU]

Yes. I saw this thing on the Discovery Channel about some Swedes who drove across Antarctica in specially outfitted Land Cruisers. They had something like 35" tires, 18 speed transmissions, and some other crazy stuff. But I'm getting off the subject. Anyways, they aired their tires down to 3 PSI.

 

[RFR2212]

Fly AU..I've seen maybe the samething, if not similar in Antartica...But were they also not traveling on some sort of terrain similar to glaciers? I could be totally off...as for the snow...I've noticed a few things....I would think that airing down would make the tire patch wider. The reason that smaller cars get better traction is because the thin tire cuts through the snow...a wider tire floats more on the top, and leaving that slippery layer of snow between the road and the tires...I'd have to say, I wouldn't change it...I have boggers which I'm starting to think may suck, but who knows...All I know, is whether your tires are aired down or full....we still gotta be safe...its snow and most everything sucks....And not to mention the people that don't know how to 4x4 and assume that since they can accelerate faster, they can stop faster or corner better....they are so wrong...I've been a nice guy and helped a few out of ditches...anyways...I cant wait for some snow here in IL...Thanks, Pete

 

[Tom Wilk]

I saw part of that documentary on Anartica as well. Pretty cool. I think that the reason they air down rather than keep the pressure up is that there is no road under all that snow. They have to float on top like you would on sand because if they dig into the snow, they will find only more snow.

My take is not to air down, unless it is REAL deep, so deep that your tires won't find the ground underneath without burying the vehicle.

 

[donkey boy]

If it comes to snow, trust a Swiss!

OK guys, there is a difference between a) driving on a street with some inches of snow, and b) driving off road on snow.

Airing the tire down has 3 good effects (besides 33 bad ones):
1. The tire touches on a wider base, which gives less ground pressure per square inch, which makes, that the tire sinks less into a soft surface.
2. Being soft, the tire can hug obstacles better, adapts its shape better to the shape of the ground, which equals more traction.
3. The tire cleans itself better from dirt and mud because the tire gets more deformated when rolling (the same as taking a dirty boot and bend it, the dirt will fell off)

Now, all these effects are desired when driving on soft ground, where there is nothing hard underneath. In situation b) off roading in deep snow, where the snow is actually so deep that you would like to float on the top of it (like walking in snow shoes) airing down and/or using wide tires is perfect.

Normally, we don't go off-roading in Iceland or the Arctics, we just want to drive on a snow covered street.
a) What we want here is a high ground pressure per square inch, for that the tire sinks through the soft stuff and finds grip on the hard surface underneath. The skinnier a tire is, and the more aggressive pattern it has to dig the snow away to reach the hard ground, the better it will work. The cold temperatures make the rubber of a tire harder, so you should equal this with a somewhat lower air pressure, no matter if there is snow or not, just as long as temperatures are around or below freezing. Specific snow tires compense this already with a softer rubber compound; this is the reason snow tires wear down so fast on dry road and warm temperatures.

Now, my recommendation: Normal winter driving, as long as the snow on the road is not higher than about 1 foot (right underneath the hub) drive with about 2-4 psi less than in summer, what you actually should do during the whole cold-cold season, but don't air down. If the snow is deeper than 1 foot, go back home and cuddle with a hot coffee and wife/girlfriend in front of the fire place. No, seriously, then you should start experimenting with airing down and go prepared as if you would hit a trail.

Have fun!

[Edited by donkey boy on 10-11-2000 at 06:35 AM]

 

[Ray Hutchinson]

Snow driving

Having grown up and learned to Drive in Maine, I can confirm / agree with what Donkeyboy says. Those folks dont run wide or soft tires in the winter, whether on any road, paved or dirt, or even driving on ice like a frozen lake. I never "offroaded" in deep snow, but from what i have learned first hand about snow, then airing down would most likely be very helpful.

 

[ExplorGM]

Snow...

Having lived in Lake Tahoe for eight years, and CT for 3 years, I agree with donkey boy. I drove a very light cj5 with a plow and 36" mud radials. They worked best when they could dig down to firm ground. They were narrow, so lbs per square inch was the ticket for traction. With my Scout,and Explorer both with wider tires, airing down a bit more worked better. Deep snow, low clearance, air down. Shallow snow, or very hard pack and plenty of clearance, keep pressures just under manufacturer's recommendations.(Not including Firestone's )
Your best bet is to go with snow tires. They are made for the job and work better than ATs or MTs because of the compound,tread, and siping.
Rick

 

[rpenner54]

Well since this is for more on-road purposes then off-road then I do agree with the others that have posted about going just a tad lower. However if you do go off-road in snow 1-3' of the white stuff, air down!

 

[freemantj]

Thanks!!

Thanks for all of the input!

My conclusion from the discussion:

Keep tires at recommended pressure on-road.

I have some Pirelli Scorpion AT's coming (255 70 R16).
They've got to be better than the Firestone's.

I hope winter is kind to y'all.

James

 

[Henry]

Re: Thanks!!

Originally posted by freemantj
I hope winter is kind to y'all.

Personally, I'm hoping it's brutal! Dead Link Removed

 

[Paul Gagnon]

I know guys who run 0-2 psi in the snow with Swampers or Boggers. It is supposed to work great. Haven't tried it myself though.

[Edited by Paul Gagnon on 10-16-2000 at 06:18 AM]

 

[RFR2212]

Ya know Paul, if I had bead lock and we got a decient amount of snow here in IL, I'd try that just for ya with my boggers...But, I have no bead locks and we tend to lack snow here.
Pete