If you are backcountry exploring, your tires can make a huge difference in where you go and whether you get home. By airing down you can gain traction by expanding the contact patch of your tire, but you’ll need to air up eventually for the road. And if you get a hole in a tire and have the tools to fix or plug it, you’ll also need to air up before proceeding down the trail, and how do you plan on doing that?
There are many styles of onboard air systems that you can take 4-wheeling. We are not going to test them all, but we will show you three options that can help you get your tires up to the pressure after airing down or repairing a puncture.
Power Tank is a line of carbon dioxide (CO2) storage tanks that are carried in your 4x4 and used to air up tires as well as run air tools. The concept is simple: After purchasing your Power Tank you take it to a fire extinguisher service shop, welding shop, or beverage shop (a place that fills kegs or soda bottles) to get it filled with liquid CO2. The liquid turns to a gas when released from the tank and inflates your tires or runs your tools. We have found that the tanks cost roughly $20 to fill depending on location, and you’ll want to weigh the tank when empty and full to know how much is left inside the tank as the gauges do not tell you the CO2 level. A lot of companies offer tanks similar to Power Tank, but few match the level of component offerings that Power Tank has. With various size tanks, a variety of tire inflators, mounting brackets, and additional tire tools like plug kits and Monster Deflator valves for quick air-downs, Power Tank is the top of the CO2 tank mountain.
We tested the 10 pound aluminum Power Tank that is made in the USA. The tank has the dual gauge regulator that shows the tank pressure and the optimal pressure for filling tires or running air tools. Plus we opted for the Xflo coupler that allows higher air flow rates (Power Tank lists 45 CFM). We also ordered the digital readout tire filler gauge.
We mounted the Power Tank in the bed of our truck on a wheelwell (the tank should be mounted no less than 30 degrees from flat for proper storage and use; vertical is better) with the supplied aluminum mount. Power Tank has a chart on its website that lists the number of tires each tank can inflate with a full tank of CO2. For example, a 10-pound Power Tank should be able to fill 40 33x12.50R15 tires by 10 psi, 20 for a 20-psi increase, and 13 for a 30-psi increase. We were able to air a 35x12.0/16 tire from 0 to 33 psi in 1 minute 30 seconds, the fastest in our test. The coiled hose from Power Tank only stretches to 18 usable feet, but it does have a coupler on the end that accepts both industrial and automotive air fittings, which is a plus.
Power Tank 10-Pound Matte Black Tank
Size (LxDxH, in): 7x7x23
Weight (lb): 25
Max air pressure (psi): 200
CFM rating: 45 @ 0 psi
Speed to air a 35-inch tire from 0 to 33 psi (min): 1:30
Usable hose length (ft): 18
Pros: Fast at filling tires, universal fitting hose coupler
Cons: Needs to be refilled, can’t be used when mounted flat, tank needs recertification test every 5 years
Any air compressor is better than none, and a compressor that works well and is inexpensive is a good compressor. The low-price compressor in our test is the portable 12-volt SmittyBilt 2781. This little blowhard retails for $149 and isn’t the fastest but still works great. It comes in a small carrying case for easy movement from one vehicle to another if you have multiple 4x4s.
The compressor kit includes rugged battery clips, a very long spiral hose, and multiple fittings for the end of the hose such as needles and blowers for filling toys, air mattresses, or similar. The hose however does not accept the more common Industrial or Automotive air fittings, but instead uses something unique. Rated at 5.65 cfm with a 1⁄3hp electric motor and a 36- to 50-amp draw, this compressor is no slouch even if it isn’t the biggest in the bunch.
The compressor has a screw-on tire valve stem fitting with an integrated pressure gauge and a max air pressure of 150 psi. There is also a claimed auto-thermal cutoff switch and a circuit breaker to protect the compressor, but we never had any issue that kicked it off.
Size (LxDxH, in): 13x5x9
Weight (lb): 20
Max air pressure (psi): 150
CFM rating: 5.65 @ 0 psi
Speed to air a 35-inch tire from 0 to 33 psi (min): 3:25 Usable hose length (ft): 31
Pros: Good price, long hose
Cons: Hose not adaptable to common fittings, slowest of test
If a tool can do more than one thing well, it’s efficient. If it does nothing well, it’s annoying. The Warn Power Plant winch with integrated air compressor is efficient. We mounted one on our Jeep two years ago and it’s still going strong. One of the nicest parts of the Power Plant is that mounting it solves the problem of where to mount an onboard compressor and how to wire it. Simply install the winch on your bumper, hook up the two heavy-gauge wires, and you are set. We are using ours as the rear winch on a custom Jeep we built for the Ultimate Adventure a few year back, but they also fit great up front and would make an excellent trailer winch (how many times have you needed to air up trailer tires on the road?).
The winch is a little taller than a normal winch. While this may seem like a hindrance for radiator cooling, it has been used on many jeeps and the airflow restriction is minimal. Warn has been offering 9,500- and 12,000-pound rated Power Plants for a while and recently revealed a pair of new and improved versions with many upgrades. The 9,500 winch has 125 of 5⁄16-inch cable, while the 12,000 version has 80 feet of 3⁄8-inch cable.
As far as the air compressor goes, the Power Plants are quick and easy for airing up tires and offer enough power to run tools as well, but they can get pretty hot. The motor that runs the compressor is a whopping 4.6 hp, and power makes heat. In our test the compressor got very hot and was burning off the caked-on mud from some prior off-road trip. We worried it was the actual motor when we saw smoke, but in fact it was just the leftover dirt. The winch controller that turns on the winch or compressor has a thermometric warning light should the winch get too hot. The winch/compressor combo is the most expensive compressor in our test, but it comes with a winch also, so there is much added value.
Warn Power Plant Dual Force HP
Size (LxDxH, in): 24.3x6.7x13.46
Weight (lb): 100
Max air pressure (psi): 100
CFM rating: 12 @ 0 psi, 5 @ 90 psi
Speed to air a 35-inch tire from 0 to 33 psi (min): 2:30
Usable hose length (ft): 21
Pros: Includes winch, easy to mount
Cons: Expensive if you only need a compressor