Airing down your 4×4’s tires is one of the most effective ways to improve its off-road performance. But like many other facets of off-roading, there are tips and tricks to make the task of airing down—and back up—quicker and easier. It’s also important to understand when and why to stop letting air out of your rig’s tires. All of this information can be called Airing Down 101.

In this piece, we’re going to delve into these topics—and more—with the help of an expert in the field. His name is Tyler Laursen, an experienced off-roader and the owner of MORRFlate. MORRFlate’s first product was a four-way tire hose kit, and the company has since expanded into a range of products that make tire deflation and inflation fast and convenient.

A modest wheel diameter paired with a large tire and beadlock wheel is arguably the best setup for airing down into the single digits. The result is a broad contact patch and a highly flexible tire. Just look at how this tire conforms to the rock—now imagine that multiplied by four, since all of the rig’s tires are aired down.

Why Air Down Your 4×4’s Tires?

When you decrease the air pressure in a tire, its contact patch increases. By default, this improves traction because more surface area of the tire is in contact with the terrain—and traction is key when you’re on the trail. As Laursen notes, “It is by far the number one thing you can do to increase your vehicle’s performance while off-roading, because off-roading is mainly a traction game.” And because you can lower the air pressure and increase the contact patch in all four of your 4×4’s tires, you benefit from a substantial combined increase in traction.

Driving in loose sand with tires at street pressure will often result in this. Even with this 4×4’s larger wheel diameter and limited sidewall, airing down would’ve helped improve flotation and likely kept the truck from getting stuck.

More Low Pressure Benefits

Lower tire pressure has many other benefits. For example, a low-pressure tire will conform to uneven rocks and roots more effectively, and provide a smoother ride for passengers (it acts like an additional suspension component). Lower tire pressure also offers better “flotation,” which is especially helpful in sand. This flotation helps the tire stay on top of the sand instead of digging in and getting stuck.

“We’re talking about the ability to decrease your vehicle’s ground pressure. Ground pressure is a fun equation that takes the weight of your vehicle and divides it by the square footage of its contact patch. The bigger the contact patch, the less your vehicle ‘weighs’ on the terrain—so you stay on top of the terrain better,” Laursen says.

An example of flotation is the difference between wearing snowshoes and not wearing them in deep snow. Snowshoes provide flotation due to their large surface area, preventing your boots from sinking into the snow and leaving you in a predicament.

The increased footprint of an aired-down tire will improve traction when climbing, and descending, rocks.

How Low Can You Go?

When you decrease tire pressure, the pressure on the tire’s bead also decreases, which can cause the tire to spin on the wheel—or even come off the wheel. Most 4×4 wheels are not designed to retain the tire’s bead at low pressure. For example, we’ve “debeaded” many tires over the years while wheeling stock vehicles in the sand with the tire pressure lowered to increase flotation. Typically, this happens when turning at high speeds.

When a tire becomes debeaded, there are basically two choices: swap on the spare tire and wheel or reseat the tire on the wheel. Both can be a hassle in the sand or on the trail. This is where beadlock wheels are a major benefit. There are several types, and they clamp the tire’s bead to the wheel. As a result, they allow you to run very low tire pressure without the risk of debeading. The extremely low tire pressure offers a significantly enhanced footprint and thus, notable traction and flotation.

Several new 4x4s from Ford, GM, and Jeep are now available with beadlock-capable wheels, and some models have been offered with special wheels in the past. For example, the 2005 Dodge Power Wagon was equipped with Alcoa forged aluminum wheels featuring a specially modified bead seat. This design increased the tire bead’s surface area and improved bead retention at low pressure.

In this photo you can see how low tire pressure allows the tire’s sidewall to conform to the rock wall in this V-notch.

There Are A Number Of Variables

How low you can go regarding tire pressure depends on your rig’s wheel and tire size, wheel design, overall vehicle weight, driving style, and other factors. As such, there are no set-in-stone values. Laursen notes that elevation and temperature also play a role in pressure selection. “Pressure in your tire will change depending on the elevation you’re wheeling at and the temperature outside. So, you may not run the same pressure in Death Valley in the middle of summer that you would up at Lake Tahoe in the fall or wintertime.”

Our advice for rigs with stock wheels is to reduce tire pressure a few pounds at a time when off-road to find the sweet spot that improves performance without increasing the risk of debeading a tire.

The right time to air down—and later air up—your 4×4’s tires is at the trailhead. Driving on aired-down tires on the street is dangerous.

When To Air Down And Up

The proper time to air down your tires is at the trailhead. Conversely, the proper time to air up your rig’s tires is before returning to the pavement. Chances are, your 4×4 has a placard on the driver-side door jamb that lists the recommended tire pressures for your vehicle. These pressures, determined by the manufacturer, are intended for street use. They factor in your 4×4’s weight, load capacity, and even fuel efficiency goals. While these pressures aren’t ideal for off-road use, they’re critical for on-road driving from both a safety and performance standpoint. Tires are not designed to be driven on the street at low pressure and the result can be overheating and failure.

This photo shows the footprint of a LT285/70R17 tire (33-inch diameter, 11.2-inch width) at 18 psi. Note how the lower pressure allows the sidewall tread elements to contact the surface to provide extra traction.

How To Air Your 4×4’s Tires Down, And Up

“So you can pick up any random stick on the side of the trail and push it into the Schrader valve, which opens the valve and lets air out of your tire. A pointed rock, a knife, or your vehicle’s keys work too. That’s how I did it when I was young. My dad would give me the keys and say, ‘All right, go deflate the Bronco’s tires,’” Laursen recalls. “I remember doing that and thinking, ‘This sucks.’”

Soon, he discovered that removing the valve core allowed the tire to deflate more quickly—and with less boredom. “The big risk there is what happened when I was a kid, and what got me banned from deflating the tires—at least by removing the valve cores,” he notes. Sometimes, the valve core would shoot out of the valve stem as it was being removed, never to be seen again.

While these methods are easy and free, many wheelers choose to use deflators that automatically lower tire pressure to a specified level. Many of these are available in the aftermarket, and each simply screws onto the valve stem. A tire pressure gauge with an integrated deflator is another option. It requires holding in a button to release air while periodically checking pressure until the target level is reached.

MORRFlate’s cool trio of Air Hub Quad hoses, Air Hub, and compressor is the ultimate way to air your 4×4’s tires up and down.

Air Down Four Tires At Once

One of the easiest ways to deflate and inflate your 4×4’s tires is with MORRFlate’s Air Hub Quad hoses, which can be combined with the Air Hub and one of the company’s powerful air compressors—designed to inflate four tires at once. With this setup, you simply attach the hoses to the Schrader valves and the Air Hub, set the desired deflation pressure, and you’re free to handle other trail prep tasks while the system automatically deflates the tires. To inflate the tires, you set the desired pressure, connect the air compressor, and the system does the rest.

Laursen summarizes the system by saying, “These will hook up all four of your tires into one centralized air system that you can then control your airflow and check your pressure and everything from one central manifold. It’s very nice. You’re not having to squat at the tires anymore while all this is going on and your time is freed up to do other things.”

The Bottom Line

Airing down your 4×4’s tires for off-road travel offers abundant benefits. “It is by far the cheapest and most effective thing you can do to increase the performance of your off-road vehicle (it’s free!),” stresses Laursen. The key is to have a plan—and the right tools—in place so airing down at the trailhead (not before) can be done quickly and easily. Learn the most effective pressure for your rig on the terrain you’re wheeling. And have the necessary equipment ready so you can return your rig’s tires to street pressure before heading back onto the pavement.

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