The trails in Arizona are best done after ‘airing down’ the tires. When you get done you have to air back up. The lower you go and the bigger the tire the longer this operation takes. I used a single MV-50 when I had 35’s and it was adequate. When I went to 37’s it was just too much for it so I bought a second MV-50 and ran them in parallel. I was pretty pleased with this setup until I did a couple of trails with my buddy that has an ARB dual compressor setup that is hard mounted. He would have the first tire done about the time I was getting the first compressor hooked up to the battery. (He also has 37” tires)
One trip I timed my entire operation and it took over 20 minutes to unpack the compressors, hook them up to the batteries, fire them up and fill the tires to about 32 psi. A few more minutes to put them back in the bags and tuck them away.
Twenty plus minutes might not seem like a lot but if you have been on the trail all day and it is getting late or you have come from the high country down to the desert and it is hot the extra time matters.
So, I picked up an ARB dual air compressor. Check out discountbandit.com for the best price.
It’s not small and it weighs about 20 pounds so I was looking for a place to mount it. The easy spot would be in the empty area where the spare tire normally goes but that is a nasty environment. I wanted it inside the cabin. I got to thinking about it and decided a great place was up high and out of the way. I picked up a piece of ¼ aluminum plate along with a couple of 1/8” L pieces for added support and attached it all to the top of the roll cage.
It’s in a good spot and out of the way. I also mounted a HAM radio to the shelf and have room for other items as well.
I decided to add an air tank as well. I had room for a 1, 2 or 3 gallon so I compromised on the 2 gallon tank. I figured this would allow me to run air tools AND also help with filling the tires. I will be able to fill up the tank before stopping at the trail end and while I am going from tire to tire the compressor will continue to operate. Here is the setup:
A drain at the bottom, a pressure release valve and a pressure gauge are some of the accessories. I was going to direct mount the feed at the top but decided to go with the coupler. It may end up leaking a bit but if something happens to the tank or its accessories I can just do a quick disconnect and go compressor only.
Here it is mounted. The fire extinguisher is in the way but it has a quick release system.
With the fire extinguisher removed I can connect the air line and see the pressure gauge. I mounted the gauge ‘upside down’ so I could more easily read the normal operating area.
So how does it work? Let’s do some comparisons.
In all of these comparisons I dropped the tire pressure to 11 psi. The accuracy of this measurement along with all of the measurements is going to have some variance but should be good enough for our comparison.
First I used my home compressor. It has an 11 gallon tank and a sticker that says 3.5 HP and a max pressure of 125 psi. I waited till it stopped running and then filled two tires.
The first tire filled to 30psi in about 78 seconds. The compressor started running after about 20 seconds and around 90 psi. The second tire was almost as fast. The compressor never stopped running and the pressure stayed around 90 psi as I was filling.
Then I tried the ARB and no air tank. After 1 minute the first tire was at 22 psi. At the 2 minute mark it was at 30 psi and around 30 seconds later it was at 35 psi. I moved to the second tire and in the end it took about 5 minutes 30 seconds to get both tires filled.
I tried it again with the air tank added to the system. I let the tank fill up before starting. After about a minute the first tire was at around 24 psi and at 2 minutes about 32 psi. I hit 35 psi at about the 2:15 mark.
When I moved from one tire to the next the compressor never turned off but did build up pressure to about 90 psi. The second tire took a bit longer but was done in about 2:30.
So the tank saves about 45 seconds on two tires. I figure on four tires it will save a bit more since the tank will continue to fill while I move from one side of the Jeep to the other.
So is the cost of the tank and accessories (along with the labor time) worth it? I would conclude a strong maybe.
Hard to say. You shave off a minute or two which can be significant if you are in a hurry or it’s hot. Another consideration is the cost of the tires. If you air down a bit more and avoid popping a tire OR air up a bit more and wear them down a bit less then maybe it’s all worth it.
Even though the tank didn’t add much benefit I do enjoy customizing the Jeep and learning new things so I got some satisfaction out of the process. As far as the compressor goes, I would recommend hard mounting whatever you have since this saves the most amount of time.