A 12-volt automotive air compressor is a great item to have along in your weekend warrior if you’re a serious off-roader who has a greater need for it than the occasional trail rider.
Tires can be aired up in minutes and if a tire repair is needed on the trail, you’re covered for re-inflating it.
Before running out and spending money on an air compressor, it’s critical to understand compressor specs so you don't buy the wrong unit that will just be money wasted without having the air really needed.
The first factor to consider when buying an air compressor to take off-roading is how it’s powered.
There are two types:
- Compressors powered off the vehicle’s cigarette lighter port.
- Those powered directly off the battery.
Those that plug into the cigarette lighter only provide 5 amps of power, which isn’t going to be enough to air up a tire.
12-volt compressors that connect directly to your off-road truck or Jeep's battery yield 25 amps or more depending on the unit, which is more than enough to air up tires.
Flow Rate and Pressure
Air pressure, measured in pounds per square inch or PSI is how much pressure the compressor can deliver air for pumping into tires and the speed at which the air is delivered is cubic feet per minute or CFM.
Ideally, you want to choose a compressor to use on your off-road truck that offers high enough PSI to fill tires to the required inflation and as high a CFM as possible while at higher pressures.
Keep in mind that the higher the PSI, the lower the CFM will be which means the compressor will pump slower the higher the pressure becomes.
A compressor’s duty cycle is how long it can run before it heats up and shuts down to cool off again.
A unit with a 100% duty cycle is one that can run indefinitely, while one with a 50% duty cycle will run a half an hour before it will need to cool.
Most smaller compressors have a duty cycle of about 33% or 20 which means they can run for 20 minutes to air up tires on your off-road truck, then require 40 minutes of rest time before they can be run again.
Take note that those with lower duty cycles usually have higher CFM, so that’s a plus even if there’s a longer rest time between uses.
Portable or On-Board
Portable compressors can be carried in your off-road truck from place to place while on-board or mounted compressors must be mounted somewhere on the vehicle for use.
Although on-board compressors may have better specs and be stronger for airing up tires, the small portable units are usually sufficient for the same jobs.
Unless you plan on doing a whole lot of airing up and down, portable models with the right specs are usually fine to include in off-road emergency gear in your off-road truck or Jeep.
Air Hose and Power Cord Length
One limitation to keep in mind when purchasing a useful air compressor to take off-road in your truck or Jeep is the length of the power cord and air hose.
Since the compressor needs to be connected to the battery to function, the combined length of the power cord and air hose should be long enough to comfortably reach the rear tires.
If it’s not, you’ll have to either take the tire off your truck or Jeep or run the compressor off a different vehicle, neither of which is very convenient when a tired needs to be aired.
If the air hose or the compressor itself doesn’t have a pressure gauge on it, buy one that can be added on.
You have to know how much pressure the compressor is putting into the tire to properly inflate it to the right PSI.
Like everything else taken in your off-road truck or Jeep, make sure the compressor you choose is made from durable, high-quality parts so it lasts with this kind of use.
The unit should be sealed with an Ingress Protection or IP rating of 55 or higher so dust and moisture won’t affect it, be preferably made with an aluminum housing, offer thermal protection, as well as noise and vibration-reduction features like rubber feet.
Choose The Right Compressor for Off-Roading Fun
A portable air compressor can be an essential piece of equipment to have in the back of any 4x4 if you do a lot of airing down
Getting the right one is critical, since a compressor that’s not strong enough to actually fill your tires to the required PSI is a waste of money.
Using the above specifications, it is pretty easy to compare compressors to choose the one for your off-road truck that fits your budget and needs!