My dad surprised me with a Harbor Freight Portable Air Compressor. We were chatting about air compressors and he started planning for our upcoming Moab trip. So, he purchased this online and had it sent to me.
clicky to see the site and specs
Last night I did a tire rotation on my BFG/AT 35x12.5x15 tires.
After the tire rotation, I aired down the front left tire to 15psi to test this thing out. The air compressor has a built in gauge to tell you how much air is in the tire, and the air nozzle screws onto the valve stem to ensure no air loss.
Before the test, I used my high-dollar low-pressure air gauge to measure and ensure that my starting point pressure was set at 15psi.
Now to set the stage, my elevation is about 6500ft and my tires, as noted above, are 35x12.5x15 BFG/AT that are in good shape, as well the weight of the vehicle was on the tire during this test.
From 15psi to 28psi I counted 6 minutes and 30 seconds. I stopped at 28psi because the built-in gauge was reading 30 psi. When I took the air nozzle off and measured the air pressure with a high-dollar low-pressure air gauge, I measured 28psi. So, in reality, it took 6 1/2 minutes for go from 15psi to 28psi, only 13psi difference. So, at this elevation, about 6500ft, the compressor pumps approximately 1 pound of air every 30 seconds.
Given this ratio and elevation, if I was to attempt to air up from trail pressure, about 10psi to street pressure, about 30psi, the Harbor Freight compressor would spend approximately 10 minutes per tire. For all 4 tires, that is about 40 minutes, given the compressor doesn't shut down due to thermal protection.
In contrast, the Power Tank I carry, does each tire in about 1 minute or less. Actually, I need to measure it for more accurate results. According to the PowerTank site
and their numbers, its 38 seconds.
The Harbor Freight air compressor is a great backup to the Power Tank or any CO2 tank, and if necessary, it will get the job done, but not very quickly. However, quickly is a relative term. What is quick for me, may not be quick enough for somebody else. So, in my own personal opinion, when the viable options are weighed out, I would prefer a CO2 tank over the Air compressor. I will still hard mount the Air Compressor and plumb it into my system so it can be a back up to the onboard ARB compressor. Redundancy is a good thing when you are out in the bush with nothing but your own resources.