With more trucks and SUVs sold than ever before, more drivers could be tempted to take to the unbeaten path. Before loading up the truck with a cooler, tent, and extra clothes to keep warm, it's good to know how to prep tires ahead of time.
Thanks to a video from Team O'Neil Rally School and host Wyatt Knox, we know everything there is to learn about deflating, or "airing down," tires just right to ensure the best performance on the trail.
Lowering tire pressures produces three key benefits for off roading. The first is drivers will actually note an increase in the vehicle's capability and performance. With less air, the vehicle will have a larger contact patch to provide more grip. This is especially helpful in mud, deep sand, or snow that the vehicle needs to float on top of rather than sink into. It will also be able to more easily crawl over larger objects.
That brings us to the second major benefit. Airing down makes things a lot easier on the driveline, suspension parts, and the vehicle as a whole. With a fully inflated tire, the ride with be harsher, but a cushier tire will absorb impacts better. Smaller twigs, stones, and other items will be absorbed before springs and struts even get a chance to do their job.
Third, passengers will likely much appreciate a smoother ride and less jarring. The softer state of the tires will make things much easier for pals, pets, and any cargo inside the vehicle while riding through a trail, which can get awfully bumpy.
While those are the main takeaways, there are plenty of other minor benefits. For example, the larger contact patches will leave less of a trace, which fits with the off roading saying "do no harm." When hitting really turbulent patches, deflated tires also provide that much more flex to travel across an area.
Of course, there are plenty of reasons we don't drive on deflated tires all the time. Low-pressure tires can't be driven at higher speeds, like on the freeway. The low air pressure can cause heat to build up and result in a blow out, and low pressure can allow the suspension to flex and cause a rollover in extreme situations. Low pressures can also adversely affect off roading by lowering ground clearance. Extremely low pressures can cause a tire to come off a wheel. And most obviously, low pressure will adversely affect fuel economy.
So what's the ideal air pressure for your tires? It depends on the size and weight of the vehicle, the volume of air in the tire, the tire's construction, and the size of the wheel lip that provides the bead.
Knox recommends airing down in 5 psi increments depending on the severity of the terrain. For example, if a tire normally holds 35 psi, it might work well at 25-30 psi on a gravel road; 20-25 psi on a bumpier trail; 15-20 psi in mud, sand, or rocky terrain; and 10-15 psi for the most technical terrain provided the vehicle has good wheels that provide plenty of purchase for the bead. You can go below 10 psi, even down to 5 or 3 psi, if you have bead-lock wheels and off-road dedicated tires. In any situation, you may want to run different pressures front to rear based on the amount of weight carried on each axle.
Those are just a few key pros and cons to deflating your tires, as well as a basic primer on what pressures to use for each situation. Wyatt has much more to say in the video above. Check it out for yourself.
—Senior Editor Kirk Bell contributed to this post