Enhance Your Off-Road Experience: The Benefits of Airing Down Tires and Tips

Letting air pressure out of your tires or “airing down” to the point of what most people would consider a flat tire, might seem like the opposite of everything you have ever learned about tires. However, in the off-road world, it is one of the single best things you can do when off the pavement.  Lowering the tire pressure of your tires has many key benefits, the biggest being that it increases the surface area of the tire tread that is interacting with the ground.  Running lower tire pressure on mountain trails helps the tire conform much better to the irregular shapes of rocks, and roots that you might incur on the trail and lets the tire wrap around the obstacle.  It also provides a much more comfortable and smoother ride over the rough terrain than a tire that is at the full pressure you would run on the street.  There is also the benefit of increased puncture resistance since the tire has some flex to it and can absorb some of the pressure that would pop a tire that was at full pressure.  While on the sand or in the snow the increased contact patch and lower ground pressure help the tire float over the surface instead of digging into it, which is why the National Parks Service requires you to air down to at least 20 pounds per square inch (psi), but is 20 psi low enough and is one pressure right for all conditions…

 There are many factors to consider when trying to figure out how much air to let out of your tires before going off-road.  Terrain type, vehicle weight, tire width, rim width, whether you have bead lock wheels, tire load rating, radial or bias-ply tires, driving style, availability of a way to reinflate your tires before driving home, and just plain personal preference all play a part in determining what psi to run your tires at off-road.  To much pressure and you will be struggling in areas that you should be floating through and too little pressure and your tire will be falling off the rim and leaving you stuck with a flat tire that needs the bead reset.  On a lighter vehicle, you might have to let more air out of the tires than on a heavy diesel truck to accomplish the same amount tire flex and on that heavy diesel, you might let more air out of the rear tires than the front to counteract the heavy engine. If you are off-road in the rocks and have a way to reinflate your tires and you have bead lock wheels it is very common to run as low as 4-5 psi; however, if you don’t have bead lock wheels then you might want to start your research into the correct tire pressure in the 12-15 range depending on your vehicle.  Always remember, whatever pressure you decide on, that you must reinflate your tires to the proper pressure before driving on the highway. 

 On my 1993 Toyota Land Cruiser, I am running the 37X11.50R17 ACCELERA Badak Xtreme and there has been a lot of trial and adjustment to find the right pressure in different situations.  Since the Badak is a very aggressive tire it has the tendency to dig in soft sand instead of float on the top; however, since the tires are mounted to bead lock wheel, the pressure can be set at a lower psi to counteract the digging. On a recent trip to the beach, I aired the tires down to 10 psi, and even on the 6000-pound Land Cruiser, they floated over the sand with ease.  Just to see the difference I aired them up to 15 psi and while they still performed well the change was noticeable especially when trying to turn in the soft sand.

 Two weeks later this same vehicle was crawling over rocks on the trails of George Washington Nation Forest, this time with the Badak’s at a lower pressure of 6 to 7 psi.  The tire’s multiple biting edges conformed to the jagged rocks and clawed their way up and over the rocks.  The sidewall of the tire exhibited good flex, especially for a radial tire.  Also running the tire at the lower pressure made the ride so much smoother.  Even when the rocks were wet the tires aggressive pattern more than made up for the lack of siping in the aggressive tread.

In the sand, the Desert Dog was a little more forgiving of running a higher tire pressure, even under a 7,500 pound Sierra 2500 with the Duramax diesel.  The less aggressive tread and wider tread width of the 35x12.50R20 helped the tire float over the sand with ease even running the tire 20 psi. When the tire pressure was dropped to 15 psi the truck moved through even the softest sand effortlessly. The Desert Dogs ability to stay on top of the soft sand made turning around in the sand painless.  The tire did not dig laterally into the sand and felt very surefooted.  While the truck I have the Desert Dogs is on, is a little big for the same rocky trails that the Badaks were used on, the same principles to airing down the tires would apply.

Whether you are using the Accelera Badak X-treme, or the Armstrong Desert Dog M/T remember to always air down when you go off-road and tread lightly.