exactly^^^... for portable the viair 400p is awesome and does my 33" fairly quick...
if I was to do it over, or when viair gives out finally...I'll be doing a engine mounted unit.

Stauns deflators is what I use for airing down...stooopid simple and quick

That's an interesting set-up. I have a SCUBA compressor so for day trips I'll usually just bring along a 19cf bottle which gets my 285/70/17 tires from 20 - 35 psi (barely). For a weekender I use a 40 cf bottle which gets me through two air-ups. Air-ups are fast but storage space in my 4runner is at a premium so I'm looking at getting a small compressor.

I've been using the Viair 400P and ARB Ez-deflator for a few years now. No issues yet and it works perfectly for my use. If I move on to an engine mounted unit it's nice to know the Viair can be used as a backup or in another vehicle.

I've used these for about 5 years and have been very happy with them. I've probably been 2-3lbs off from the settings, but so what, that's not going to be the difference between me getting over an obstacle or not.

10lbs off from the settings of all 4 def seems like something is wrong. Sorry you got a bad batch.

The ARB portable single compressor is great if you want quality and reliability at a fair price. I've loaned it other drivers without air on trail rides and it's been super helpful.

I've only recently upgraded to the ARB portable dual because the 34s get the single compressor a little hot, I've gotten my money's worth out of the single, and the double has an air tank (air tools). I'm not a fan of installed compressors at all.

You should give Stauns a try, I set mine to 18 psi, and its always on the money.

I've got a Viar 450C (constant duty) mounted in the cargo area of my Bronco (offroad rig), it's plumbed to a 2.5 gallon tank..The compressor is super quiet and takes a shade under 3 minutes to fill the tank and I can inflate a 37 inch tire, from 15 to 25 lbs in about 30 seconds with the tank full.

Been very happy with this set up.

Good to hear a couple of positive notes on them, I’ll give them a call, I’ve only had them a couple months.

No rookie to airing down I have been doing since people would look at you puzzled Couple pounds variance sure but yeah mine aren’t working like they should.

I have a set of Coyote Staun II’s and they’re rock solid (set at 15lbs), also a set of trailheads that are pretty decent (set at 20lbs) and a ARB EZ I got for free from a subscription to Overland Journal. I want to try a set of on the fly adjustable.

Why?

Speaking of the dual compressor;

It adds weight to an awkward place on the vehicle--most are mounted in the engine bay. I'm not a fan of adding anything to the engine bay that isn't directly engine related. If it isn't mounted in the engine bay, it presents other challenges like access with the hose, running power, etc..

If you're interested in adding the air tank to the setup, that presents a mounting challenge (and weight issue) also. My portable compressor, and recovery gear, have always sat right behind the front seats, on the floor board, between the axles.

Mostly, I like the versatility of a portable compressor. I can loan it to someone with a tire issue for quick refills, use an air tool, etc., while on the trail and I don't have to be pulled up next to them in order to reach it.

While I stated earlier that if I were to do it again it would be an engine mounted unit. I must say these are very good points. Thanks for the insight.

Your 400p will probably never give out. I burned out several MV-50s and finally bought a 400P back in 2012, IIRC. I air up several times a week at least, often several times a day.

Around 2013 I mounted my 400P in my engine bay with a pressure switch, check valve, manifold, along with an additional 400h to give me a bit over 5 cfm to a quick connect fitting on my front bumper.

With my aftermarket TPMS that has a display for each tire pressure, airing up is as easy as a quick connect at the bumper and lock on chuck at the wheel, then watch the display from in the cab.

I have bought lots of deflators... All crap. Best way to air down is to pull a valve core, wait 20-30 seconds, pull the other on same side, start checking the first and reinstall the core when at desired pressure, rinse/repeat.

Carry spare valve cores, you should anyway

Sound points, thank you. But as someone who doesn't have a compressor yet, my questions in response are:

1. How much does the ARB dual compressor weigh vs a portable one and is it enough to make a difference as to where it's mounted/stored?

2. I can imagine having the compressor in the engine bay frees up storage/sitting space in the cabin? If you store a compressor on the floor behind the front seats, where do people's legs and/or other gear go?

3. What is the air-up time of your portable compressor vs the ARB dual?

Can't answer your other questions but my Viair 88P portable compressor's bag is around the size of a kleenex box, maybe a few inches taller. It's easy to stash in my 56qt Plano Sportsman box along with my tools, jumpercables, a folded tarp, tire gauge and deflators, and some other misc stuff. Stays in my hatch area full time.

The viair looks like ~1.5 CFM which seems low compared to others I see mentioned like the Smittybilt or the 400p. How do you find airing up with this smaller one - how long does it actually end up taking you?