Off-Roading Tire Pressure: When You Should Air Down And Why

Traditional automotive logic dictates that you should always keep your tires at their optimal pressure, as dictated by the driver's side placard. After all, proper air pressure helps your vehicle to move safely and cleanly along a flat road while protecting the metal and mechanical components of your wheels. The idea of driving a car with partially deflated tires seems like a bad idea on paper, and in most circumstances, it is. However, there is one particular instance where partially deflated tires may actually serve you better: off-roading.

Off-roading vehicles like Jeeps have stronger, more robust tires and wheels for unpaved, uneven terrain. However, there are some terrain types that even these kinds of tires may have difficulty tackling. It's in this particular case where partially deflating your tires, or "airing down" to use the common terminology, can actually go a long way toward improving your drive and protecting your vehicle. Before you go poking a hole in your tires, you should know that airing down should only be used on certain types of terrain and only if you deem it to be necessary.

Why exactly would you want to defy what you learned in driver's ed and let some air out of your off-roader's tires? The answer, somewhat ironically, is stability and traction. While properly inflated tires are ideal if you're driving on a flat, uniform road, things change a bit when you're on an off-roading adventure. A firm, round tire may not actually be the best choice for maintaining your vehicle's stability, not to mention keeping things comfortable for you and any passengers.

When you air down your off-roader's tires, they flatten out slightly. This increases the surface area of the tire that makes contact with the road. By increasing that contact patch, your tires become better at gripping the terrain. It's kind of like the difference between standing on your tippy toes versus standing flat on your splayed-out feet. Additionally, when tires are aired down, they become looser and more flexible. This allows them to more easily roll over larger obstacles that a fully inflated tire would just bounce off of. All of this amounts to greater traction on a rough surface, not to mention less bouncing and rumbling for you in the cabin.

While airing down can be helpful for your off-road vehicle's driving ability, it's of the utmost importance that you only do it on the right kinds of terrain. If you tried to air down on the highway, you'd just build up friction and heat in your wheel wells, which could lead to a catastrophic blowout.

Instead, airing down is best saved for when you need to drive slowly and deliberately over undeveloped, uneven terrain. This includes mountains covered with large rocks, desert areas with large patches of loose sand or gravel, and muddy or snowy surfaces. Aired-down tires will roll more easily over rocks and up cliffs thanks to their grippy contact patches. The same is true for loose terrain like sand or mud; that increased surface area will help to prevent your vehicle from sinking into the muck and getting stuck.

If you're planning on airing down, make sure you do it right before you need to move over uneven terrain, and with the proper equipment. Use a portable air compressor to safely let the air out of your tires, checking their precise levels with a pressure gauge as you go. As soon as you've passed the uneven terrain and are back on uniform pavement, you should reinflate your tires to their proper levels right away, again using a portable air compressor.