SEE THE PHOTO FOR A REPRESENTATION OF THE DIFFERENCE AIRING DOWN MAKES TO YOUR TIRES AND TRACTION PATCH: (Result may vary)

Airing down (DEEP Snow Edition)

NOTE: This is about recreational OFF-PAVEMENT driving in DEEP (think 2 feet+) snow. It is not about driving around town in 4 inches of snow in your smart car or your pickup in half a foot of snow on the highway. There are places and conditions where tire chains and so-called pizza-cutter tires work great. But deep, wet snow on a 4x4 trail is seldom such a place. (They can help in dry, powdery snow or on ice, though.) Once the snow is deeper than the point where your vehicle frames out before your tires can reach the ground, "cutting through" (like resistance) is futile. And we are talking about wheeling in snow 2 feet, 4 feet, or even deeper while going up and down mountain 4x4 trails.

Now that we have set the scene...

We air down in the summer to increase our traction on loose dirt and rocks, but in reality, it is more about smoothing out the rough and bumpy trails. I often reduce tire pressure to around 10 to 15 PSI for those summer rides. However, we frequently go lower, far lower, for deep snow wheeling.

Food for thought: An "average person standing on both feet exerts approximately 16 PSI on whatever they are standing on. Snowshoes can lower that to 1 PSI, allowing a person to sink very little into the snow and travel with less effort. The typical ground pressure for a snowcat tractor ranges from 0.8 PSI to 1.5 PSI, allowing them to stay on top of the snow. We are doing something similar, just with a full-size 4x4. In my case, I go from sinking in snow with a ground pressure of about 25 pounds per square inch in my Jeep to (hopefully) floating around the top at around 6 pounds per square inch. Here is how.

I call western Montana home. Here, our mountain 4x4 trails often have deep snow and/or deep drifts for six to eight months of the year. If we want to enjoy our forests during the majority of the year, we either need to take up skiing, get a snowmobile, or learn to enjoy 4x4 off-roading in deep snow. That is, wheeling in and on 2-3-5 feet or more of snow. Guess which one I chose. It is simple: When it comes to off-roading, some people have mud to play in, like in Florida, while others have rocks or sand, like at Moab, but here, as often as not, we have snow on our playground.

As with the snowshoes mentioned above, if we want to (more or less) stay on top of the snow, and we do, we need a bigger footprint. Well, a bigger tire footprint or contact patch, in this case. It is all about spreading out the weight. Cutting through may be fine for a foot of snow, but you likely need to be on top for two or more feet of wet, packable snow. So, we need to create floatation. Since I can't put monster LT475/70 R17 Nokian Hakkapeliitta 44 tires, I have to do it another way. I will have to get that larger footprint by lowering the air pressure in my tires until the contact patch functions more like a section of track and less like a tire at normal street pressures. Done right, it really is a pretty neat trick.

So, how low are we talking about? You will have to figure that out for yourself. Some may find that 8 PSI is good in many circumstances, which is where I usually am. In deep snow, I start at 8 PSI and adjust as needed. Changing by just 1/2 PSI can make a considerable difference at such low pressures. For me and my rig, that is, more often than not, just right. But here is the rub: What *YOU* can or should air down to can be different from what I do. It can be different for every vehicle, weight, tire & wheel combination, and even for the consistency of the snow. That is something YOU have to work out for YOUR rig. Trying different pressures in different types of snow just to see how they perform is part of the fun.   

I have been as low as 4.5 PSI (yes, without beadlocks) with my 35" tires. That is as low as I go with my current tires, and it is only for deep snow and very slow speeds. 10 MPH will be as fast as I go at those pressures, though I will usually be slower. Remember, I'm a daily driver. I don't have the massive tires or big engine to really power through deep snow, as some do, so I have to crawl as often as not. After all, I will have to drive it home.

OK, Goldilocks, you should remember that airing down really low like this is baby bear-type stuff. You know, not too high and not too low. It is definitely not a race-to-zero PSI. If your tire pressures are too low, you can debead a tire. If it is too high, you give up traction and floatation. You should go no lower than you have to for the floatation & traction needed. Aim for "just right," not for some silly bragging rights about who went lower. Leave that "I run 1 PSI" stuff to the big-tire and beadlocks buggy types who towed to the trail. They are set up for that, but we daily driver types usually are not. I do enjoy watching their videos, though.

CAUTION: The lower you go, the slower you go. Airing down to these levels can usually be done without beadlock wheels, depending on your tire/wheel combo and driving technique. The people I snow wheel with the most, and I have not utilized beadlocks in the past. However, if you are a gas pedal junkie and use phrases like "just send it" or "give it the onion," you may need to stay at higher pressures or get beadlock wheels.

TIP: This technique is great for the "packable" snow (think: good snowball-type snow) we often get around here, but it is not as effective in dry powdery snow or sugar (faceted) snow. Still, it is far better than running full street pressures.

There is more to deep snow wheeling than just lowering your tire pressure. As with most things concerning serious off-roading, I suggest you try this only when accompanied by some experienced 4x4 off-roaders. They can teach you about snow wheeling and airing down, AND they can be handy to have close by when things go wrong. They will go wrong, and you will get stuck. If this were super easy, it would not be nearly as fun. But, as with most off-roading, practice and proper technique will get you farther than most would imagine possible, and, in this case, it can be great winter fun for the right people.

NEVER ATTEMPT THE LOW TIRE PRESSURES DISCUSSED HERE WHEN DRIVING ON PAVEMENT, HARD OR DRY SURFACES, OR AT SPEEDS ABOVE A FEW MPH. BAD THINGS CAN & WILL HAPPEN!!

Remember a way to air up your tires to safe highway pressures before getting back on the pavement.  

Wheel Safe!!

©2024 Richard Hiltz