I am thinking of getting an air compressor before doing more off-roading (I'm a beginner). I am told that the ARB single model 12v model for installation will not fit my 24 Wildtrac. Is there another that will or does it make just as much sense to buy the same version in a kit that you just carry with you. Advantage to the kit in a box is portable and seems to have all the components needed? Also, why is there single and double motor versions of the compressor.
Airing down is one of the best things you can do to improve your off-road performance in any vehicle. When it comes time to drive home, then you need to air up or drive very slowly (rule of thumb: don't exceed 2 times your tire pressure in mph). Two basic ways to go are CO2 (Powertank is one example) and compressors, either portable or installed. CO2 gives you virtually unlimited power for faster inflation, power tools, cleaning, or whatever you can think of. The downside is you periodically have to take it to a shop to get it refilled. Additionally, you have to carry that tank around somehow. Where I live, tanks are the preferred inflation method for fire departments, rescue personnel, and so on. Compressors are slower, less powerful, and do require some maintenance. I have and use both, it just depends on what I am doing.
The two most important numbers to watch for in a compressor are duty cycle and air flow. Duty cycle is expressed as a percentage of an hour. A 50% duty cycle means the compressor can run for a total of 30 minutes before it has to shut down and be allowed to cool. A 100% duty cycle means the compressor can run for a full hour. Air flow is expressed in CFM, or Cubic Feet per Minute. I have a compressor that has a 100% duty cycle that puts out 0.9 CFM with a maximum pressure of 160 psi. I use this for a large, heavy vehicle with large tires that also require high pressures. It is time consuming, but effective. I also have a compressor with a 50% duty cycle that puts out 10.6 CFM. It's extremely fast, and probably sees the most use for regular vehicles through a four tire inflation system. Setting up all the hoses and the compressor takes longer than filling the tires from about 16 psi to 38 psi.
I have mounted in my old Toyota an ARB single motor compressor. Having it mounted in the engine bay is convenient, but subjects it to heat and therefore I have to be a bit more careful about maintenance. ARB (and other manufacturers) offer dual motor versions to increase air flow, making them much faster. Personally, the single motor has worked fine for me, but that vehicle has 31" tires so your case may be different.
Your tire size, pressure required, and whether you intend to only air up just your vehicle or also others are things to think about before purchasing. I have found the portable air compressor to be the best all around solution for me, as I am frequently called to attend to the tires of others. Becky, if you are reading this, that's for you!