Off-Road Air Compressor Guide

One of the most critical pieces of gear for off-roading and overlanding is an off-road air compressor for refilling your tires. The ability to inflate your tires after airing down, whether voluntarily or involuntarily (a.k.a, “a flat”), is one of the pillars of being safe and having fun off-road.

Many owners of Jeeps, Land Cruisers, Broncos, Tacomas, and other SUVs and trucks will also adjust their air pressure on the trail depending on the terrain. An air compressor will also come in handy in case you need to reduce your tire pressure to get more traction in a recovery situation. This guide will explain the different types of off-road air compressors, how they are used, and offers some tips on choosing the right compressor for your needs.

In case you are looking for a quick recommendation, I’m a fan of the Viair 400P Air Compressor, which can inflate tires up to 35 inches (the size on my Jeep). For larger tires (up to 37 inches), Viair’s 440P compressor will do the trick. For an onboard air compressor, take a look at ARB’s 12 Volt Twin Onboard Air Compressor.

Off-Road Air Compressor Recommendations

Here are all of our recommendations for both portable and onboard compressors. We’ve purposely picked compressors with the capacity to inflate most sized tires used in off-roading and overlanding.

Best Portable Air Compressors

For Tires Under 35 inches

Viair 400P Air Compressor

Viair 400P is a solid choice for an air compressor for a vehicle-based adventure. It’s relatively affordable, reliable, and has enough power (2.4 CFM) to fairly quickly inflate off-road tires up to 35 inches. I’ve used this model for years and have no complaints.

Top-of-the-Line

ARB 12V High-Performance Portable Air Compressor

ARB makes some of the toughest overlanding and off-road equipment around, and their portable 12V compressor is no exception. The compressor delivers 2.65 CFM (on an empty tire) for quick inflation and comes in a sturdy carry case designed to withstand rugged use.

Best on a budget

Smittybilt 2781 5.65 CFM Universal Air Compressor

• 5.65 CFM inflation rate

• Rapid inflation

• Good value

Best Onboard Air Compressors

There are fewer onboard air compressors on the market, as they are more of a specialty item and require installation.

Editor’s Pick

ARB 12v Onboard Air Compressor

• 3.08 CFM inflation rate

• Leading off-road company

• Universal fit

Uses of Air Compressors

Air compressors used while off-roading have two tire-related purposes. The most common use comes after you deflate tires to improve traction, prevent tire damage, and soften the ride for you and your passengers while on the trail.

In that case, you use a 4×4 air compressor to reinflate the tires when leaving the trail for the pavement or adjust mid-trail to adapt to changing terrain.

The other primary use of an off-road air compressor for tires is reinflating a tire you’ve repaired on the trail–for instance, when you’ve damaged two tires and you’ve only got one spare.

Some air compressors can also power axle differential lockers and air tools, which we’ll discuss further below.

Off-Road Air Compressor Types

There are two common types of tire-inflating air compressors: onboard and portable. A third option, popular among offroad racers and hardcore wheelers, is portable air tanks filled with CO2 or nitrogen that rapidly inflate a tire as the gas expands.

Onboard Air Compressors

Onboard air compressors are mounted on your vehicle, in the engine bay, or somewhere else on your vehicle and remain wired to the battery. They offer convenience, as they are already connected and ready to go when you need them.

They also typically serve multiple purposes, as on-board air compressors also power pneumatic control for air-lockers for differentials in axles. Larger onboard compressors can also power air tools, such as air impact wrenches for removing wheel lugs.

Typically, when an onboard system is installed, switches are integrated into the dash or somewhere else on the vehicle so the differentials can be locked from inside the cab. No more climbing out and twisting the hub on the wheels like in the olden days.

• Pros: Convenience on the trail; multiple uses, including powering air lockers and tools

• Cons: High cost of initial installation; might not fit some engine bays without modifications; upgrades and repairs to the compressor are more costly/time-consuming

Portable Off-Road Air Compressors

Portable off-road compressors are carried in a bag or case that you take in and out of your vehicle as needed and are clipped to the battery terminals when needed. Smaller models can often plug into cigarette lighter ports, but these models may be too small for larger truck tires.

Portable air compressors offer more flexibility than onboard units, as you can move them between vehicles. You can also move them around (as far as the battery clip wires will allow) so you don’t have to stretch the air hose so far to reach the tire valves.

That said, each time you use a portable air compressor unit, you have to unpack it, connect it to the battery, let it cool down, and then pack it back up. It’s more hassle and eats into trail time.

• Pros: Relatively inexpensive; no installation required; flexibility to move unit around

• Cons: Hassle to unpack, use, and pack backup; another thing to remember to pack; takes up room inside the vehicle

Portable CO2 and Nitrogen Tanks

Portable tanks filled with carbon dioxide or nitrogen look like something a SCUBA diver would wear on their back (don’t try breathing out of them!). These tanks offer rapid inflation, as these gases can be compressed more than oxygen in the tank but expand greatly when put into a tire.

If you are going offroad quite a bit or have large tires that take a long time to fill, these can really help you save time. However, the amount of gas in the tank is finite, and so you’ll still want to bring along a compressor powered by your engine’s battery as a backup.

• Pros: Rapid tire inflation saves time on the trail; fill large tires (35 inches +) more easily

• Cons: High cost, especially since you’ll need another air compressor as well; finite number of tire inflations; needs to be refilled, which requires time and money; large tanks take up space in car and add cargo weight

Off-Road Air Compressor Features

Here’s an overview of the various parts of a 4×4 air compressor. I’ve included some of the ratings, such as pressure, duty cycle, and airflow, that you can use to determine which one will suit your vehicle and needs and provide guidance on how to use it.

Parts of an Air Compressor

Air compressors typically have these essential parts:

MotorOn reciprocating air compressors, the type used in off-roading, the motor powers the piston in the compression mechanism.

Compression Mechanism In the compression mechanism, a valve allows air to be drawn into a cylinder. A piston then forces that air through the air hose and into the tire. This cycle repeats until your tire is inflated. Air HoseThe air hose carries air from the compressor to the tire. For portable air compressors, it’s essential to get a long enough air hose that you can reach all of the tires on your car when your air compressor is connected to the battery or cigarette outlet.

Tire chuckThe tire chuck is the part of the compressor that connects to the valve stem of your tires. For compressors used in off-roading, it’s recommended that the chuck have a built-in deflator and inline pressure gauge.

Power cord/wiringThe power cord or wiring (in the case of an onboard model) connects the compressor to a power source, whether it’s directly the vehicle’s battery or through a cigarette outlet.

Air Compressor Ratings

Compressors used for off-roading are typically rated according to the following parameters:

Tire size: Some manufacturers do the math for you and tell you what model compressor is good for a given tire size. Typically, this comes down to the compressor’s airflow capacity (measured as CFM), which is explained below.

Pounds per square inch (PSI): The force of air that the compressor can deliver. PSI is particularly important for running air tools, but most off-road air compressors deliver plenty of pressure to inflate truck tires, so PSI isn’t much of a consideration.

Cubic feet per minute (CFM): The air volume the compressor can supply per minute. CPM tells you how fast a compressor can inflate a tire while running–with run time depending on the duty cycle (see below).

Having a high enough CFM is important for inflating large truck tires, and high-CFM compressors will speed up the inflation of any tire. If you have the budget, it’s worth getting a compressor with a higher CFM vs. a lower CFM, just for the time savings.

Duty cycle: Compressors alternate on/off cycles to give the compressor engine a break and prevent overheating. The ratio of on-to-off time required during a 1-hour cycle is the duty cycle rating. For instance, a compressor with a 50% duty cycle can run for 30 minutes during an hour.

In hot weather, the cooldown time will increase, as the compressor will heat up faster. If you get a compressor that is too small for your tires, you won’t be able to fill them all before the compressor needs a rest.

Voltage: Air compressors used in off-roading are typically 12—or 24-volt models. Larger compressors require higher voltage and deliver higher airflow and pressure.

For inflating tires for off-roading, a tire size rating (if available) is the handiest measure for deciding what compressor to buy. If a straightforward tire-size guide isn’t available, use the other ratings to choose the right machine for your needs.

This table shows a few popular portable air compressors as examples of different ratings and tire sizes:

How to Choose an Off-road Air Compressor

On-board or portable?

Whether you choose an onboard or portable air compressor may depend on whether you have air lockers on your axle differential. If you do have air lockers or are planning to install them, it’s probably worth getting a large enough air compressor unit that you can also use for tire inflation.

Other pros, cons, and considerations are outlined above in the section on the two types of compressors. In my opinion, if you don’t have air lockers, a portable compressor is a more flexible and cheaper option than installing an onboard unit.

How big are your tires?

The volume required to inflate your tires will set some basic parameters around your choice of air compressor. You’ll die from boredom waiting for an underpowered air compressor to inflate a large off-road tire (say, anything 33″ or bigger). If you exceed the duty cycle rating before getting all of your tires pumped up, you’ll have to wait to let the engine cool down before finishing. So it’s important to make sure you have a compressor that’s powerful enough to at least get all four tires aired up before needing a break.

Manufacturers typically offer guidance on which models of their off-road air compressors are good for different-sized tires. Models appropriate for larger truck tires typically connect directly to vehicle battery terminals and don’t plug into cigarette lighter outlets (are we still calling them that?), as the outlets aren’t rated for high enough amperage.

Check your outlet rating to find out how much amperage it can handle.

But, really, how patient are you?

More powerful compressors push more significant volumes of air per minute, hence filling tires more quickly. Put simply, the faster you want to air up, the more powerful the air compressor you should get. If you really want to speed up the process, consider a pre-filled CO2 or nitrogen tank system.

What manufacturer?

A number of companies make portable air compressors well-suited for off-roading and overlanding.

At the high end, the Australian company ARB makes on-board and portable off-road air compressors that are considered the gold standard. You’ll pay for quality. A bit more affordable, California-based VIAIR also makes both onboard and portable compressors and offers a wide range of models. These are solid machines for a reasonable price.

If you’re looking for a budget option, Smittybilt, also based in California, makes two portable compressor models (along with everything else under the sun). Smittybilt makes a lot of stuff, so this isn’t a specialty for them. You get what you pay for, but if you’re not putting your compressor under heavy use, these might be just fine.

Does it have a deflation mechanism?

Airing down your tires can also take time. Fortunately, some air compressor valve chucks have built-in mechanisms that release the air from the tire without you having to stand there holding down the valve stem. These are worth having.

That said, some tire gauges come with this as well, and you could buy one of those separately for airing down. We own an extra tire gauge that locks open so that two tires can be deflated at once.

You’ll want to consider getting dedicated tire deflators if you are going off-road with any regularity. Check out our article on tire deflators for more information.

Conclusion

Air compressors are one of the first things anyone planning to head off-road should purchase. Airing down your tires on rough terrain has many benefits, and you’ll need a way to reinflate them. Even if you have a spare tire, there is a chance you may need to repair and reinflate a tire, in which case you’ll need a compressor.

While you can find a compressor that is capable of filling your tires slowly, we recommend getting one that’s a bit larger to speed things up — if you can afford it. Go a bit larger if you have plans to put bigger wheels on your vehicle. It’s a good investment.

Also, don’t forget to bring other recovery gear to get yourself out of sticky situations, such as an off-road shovel, recovery straps, and an off-road jack or two.

Off-road Air Compressor FAQs

Reducing the pressure in your tires while driving off-road is one of the easiest ways to improve traction and ride comfort. An air compressor is essential for reinflating tires after you leave the trail. While you don’t absolutely need to have an air compressor when you start off-roading or overlanding, we recommend you make it one of the first pieces of gear you buy.

An air compressor is used to reinflate tires after airing down while on the trail. The air compressor uses electricity to power the motor and force air into the tire.

CFM stands for cubic feet per minute and represents the amount of air a compressor can produce at a given pressure per minute. A higher CFM means a compressor can produce more air per minute. In off-roading, the higher the CFM the faster you can inflate your tires.

PSI stands for pounds per square inch and indicates the force of pressure (not airflow) that a compressor can produce. In the context of reinflating tires, CFM is typically more important than PSI, as most compressors used in off-roading produce adequate PSI to inflate a tire. If you plan to power air tools or air lockers, however, a minimum PSI may be required.

Duty cycle refers to how long an air compressor can run before the motor needs to rest. For off-roading, it’s important to pick a compressor that has a duty cycle that will allow you to reinflate all four of your tires before the compressor needs to rest. Otherwise, you’ll be waiting around a long time with partially inflated tires.

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