I wouldn't recommend the small or medium ARB permanent mount compressors for airing up tires. If you'll look at their website, they are not really rated for it and I know several people who've burned them up using them for things other than actuating the diff locks. Will they do it? Yes. Does it put a lot of stress on the compressor? Definitely. Older models were rated as "continuous duty" and they still burned up.
If you HAVE to air up a tire....take your time. Let the compressor cool down as you fill the tire. If it's a big tire, it may take a REALLY long time to fill it without cooking the compressor.
Viairs are designed to fill tires first and foremost, you can also run an ARB. Old design arbs had a max pressure of 105 psi. The newer ones IIRC, are about 95 psi. DO NOT exceed the recommended pressure for the unit or you WILL blow out the seals. Double check my numbers before committing to a pressure switch for you locker. I know Campbell Ent. runs them at the lowest pressure that they will actuate so it protects the seals....I wanna say that was at 65 psi.
I'd get rid of all the fancy solenoid switches ARB supplies with the locker and go straight to an air switch. Less parts to have problems with means less likelihood of a trail breakdown . You can buy cheapies made of plastic and steel or you can buy really nice (and expensive) ones made from brass with steel toggles. I think the nice ones are $40 a piece, the plastics are about $8-15. You can get the plastic ones from a big rig (18 wheeler) supplier. The brass ones are available through Sun Performance. Sun Performance also sells pressure switches and one way valves to plumb everything correctly.
Personally, I'd recommend buying the ARB compressor for the air locker and ALSO buying a Viair to fill tires....it never hurts to have a backup air source when you run air lockers....if something fails you are open diff'd and that may mean not getting off the trail.
Let's face it: if it was a hard enough trail that it required lockers to get in, you'll need them to get out.
The other option (and possibly a better one) for filling tires is a good 20 lb CO2 tank. It can do double duty as your welder's gas and 20 lbs will get you the most economical fill (since the price per pound is relatively low, it's the hook up that costs the coin...so 10, 15 or 20# makes very little difference in price overall). I got 76 fills from 10 psi up to 30 on 33x12.5R15 tires back in the day. You can go for quite a while with a fill of about $17-23. The tank set up with regulator and hose is about $200 if you piece it together from welding shops.
If you go with a Viair, you'll still need a 2.5 gallon tank to give you the volume you'd need to reseat a bead. That's another item you have to buy and it adds to the cost of the set up significantly.
HTH,
Sean
