On-board air solution for super singles

[lds]

Dreaming of a motorhome on an F450/F550 or Ram 4500/5500 with some big super singles, probably either 335/80R20 or 365/80R20. Curious what folks are using to re-inflate these big tires in the field after airing down.

I was thinking the 12 volt Oasis air compressor would be a great choice, but my rough calculations come up with over a 7 minute fill time per tire with the 365/80R20 from 10PSI to 95PSI ( max load pressure) or about 5 minutes per tire on the 335/80R20 from 10PSI to 80PSI ( max load pressure ). 20-30 minutes to get back up to street pressure seems pretty slow to me. The underhood engine-driven and PTO compressors I've found make a lot of air ( 40 - 150CFM ) but are pretty expensive around ~$8,000 -$12,000 systems. The "power-tank" ( CO2 ) is supposed to be really fast but it looks like a 20# cylinder would probably only refill your 4 super-singles once before needing recharged - I think it's awesome how fast these are supposed to fill the tires but if you have to go to the gas place to exchange/refill the tank every time you get to town then it didn't really save you any time.

What do you use to air up big tires ?

 

[javajoe79]

Realistically, airing down doesn’t need to happen as often as some people think but if I were you I’d run a decent sized tank and a couple compressors like viair. Use two compressors that would be rated for your tire size on their own.

 

[IdaSHO]

Big tires and high PSI, you will have to be pretty patient with whatever off the shelf electric setup you run.

We air down every so often from 60/70 to 30/40 front and rear, and when refilling our 35's using the single Vaiar, the last 10 psi from 60-70 takes a bit.
But I went with the 100% duty cycle compressor for that exact reason. I expected it to take a while. So its nice to know the compressor wont self destruct during long air-up sessions.

95 PSI? yeah, that's going to take a while.

 

[Chorky]

to add to javajoe I would also question the reasoning to air that big of a tire (with that much weight) down to 10 psi. that seems super low and honestly pretty sketch. Most people I see with super singles are hauling some serious weight. just seems like a bad idea to me. That being said, I think if you are airing down often, and need to pump all the way to 95 consistently, a old school gas compressor might be the better option.... or a small home depot unit that can run on an inverter. Seems a big task even for dual viair's at 100%. they do have a new one that is 100% duty at 200 psi. 485C Gen.2 Dual OBA | VIAIR Corporation But getting a 10 gal tank to have that initial oomph would be good. Another thing to keep in mind is the amp draw. even at 50 amps, 4 tires... thats some pretty serious power requirements. I mean for my own truck I'm looking at dual viair's to air up 35's and I'm looking at needing 8 ga wire.

 

[billiebob]

Most compressors stress/advertise psi which is irrelevant, CFMs are all that count airing up... Look at the compressor stats and buy the one with massive cfms and a 60psi peak......

ps, on agreement with the "air down" critics
unless you are in sand dunes or trying to climb a waterfall...... airing down is all hype....

sure I will get slagged for that comment but in 50 years of wheeling I have past soooo many wheelers airing down or up it is a joke.

 

[Peter_n_Margaret]

3 options to consider (in descending order)..
1. Run a 110V compressor from your inverter. Capacity is only limited by your power supply.
2. "Endless Air" belt driven modified A/C compressor. Endless Air Compressor - Prices for Endless Air Compressors, Mounting Kits, Receivers and Accessories.
3. PX07 12V compressor. The best 12V compressor I know about. Boss 12 volt Air Compressor Complete | Boss Air Suspension
Cheers,
Peter
OKA196 motorhome

 

[Superduty]

ARB Dual Compressor should work.

 

[RoyJ]

If the OP feels an Oasis is too slow, none of the recommendations would work. ARB twin, dual Viair, Puma, ExetremeAire are significantly slower. Even the most powerful 110V is slower.

OP - do you really need a 365/80 @ 95 psi? That's 16500 lbs axle weight! If so, then the minimum air down pressure is 35psi. You only (affordable) option would be a 13hp gas compressor, 25 cfm @ 175psi.

I have an XD4000 on order, but I'm only doing 37x13.5 tires @ 65psi.

 

[ripperj]

OP is putting the cart before the horse.

Stop dreaming about the “motor home”, buy or build it, drive it for a while and see what’s what.

You will probably find the realities of trying to off-road a beast of a camper to be such that airing down is irrelevant.

Worrying about airing up and down a non-existent tire on a nonexistent motorhome is just a mental exercise and or a troll post.


Sent from my iPhone using Tapatalk Pro

 

[1stDeuce]

First, thanks for believing in airing down. It does help with traction, and keeps trail and road damage to a minimum. Here in the SW, that is just about the only way to get a decent ride over our miles and miles of washboard gravel and dirt roads... It also actually helps heal washboarded dirt roads, and it helps prevent the formation of more washboard on all soft surface roads. All of these things are important to the people who actually live here and drive these roads all the time... These new pickups with TPMS and 80psi in the back tires are literally destroying our roads...
I think the compressor recommendations above are pretty good but I'll add a strategy that I use with my 12v compressors that works well too... Most of the higher CFM 12 volt compressors draw a LOT of current, and slow right down as the pressure builds abouve 50psi or so. Just a guess, but going from 50 to 60 probably takes as long as going from 30 to 50, and from 60 to 70 takes as long as going from 30 to 60... This is really true of all compressors, but seems painfully obvious with the relatively low CFM 12v units in particular.

My suggestion is that instead of trying to get to 95 psi, just air up to a level that allows you to scoot down the road to the next real gas station and use their shop air to get to highway pressure. A few miles at reduced pressure is not going to cause a blowout, or even much wear, especially if it isn't 115F out and you're not doing 85mph... In my case, for extended highway travel, I like 75psi in my rear tires with the truck camper on. I run 60psi if I'm staying somewhat local for the improved ride, and as a tradeoff so I don't feel the need to air down for shorter segments of rough back roads. When I do air down, it's usually 30-45psi, depending on terrain, speed, and how far I have to go. I have a viair 400c compressor and almost never air up to more than about 50psi with the 12v compressor during the day. Usually, that's plenty to go whatever distance I need to go to get to a real compressor, or if there isn't one, I'll air up the rest of the way when we make camp, or stop for lunch, or whatever opportunity has me stopped already.

Managing fillups like this keeps me moving more, and wiating for my little 12v compressor less. FWIW, you probably won't need 95 psi in those tires anyway, as you're not likely to be anywhere near the ~10k load capacity at 95psi...

 

[billiebob]

Look at engine driven air compressors permanently mounted. Tire service trucks tend to be F450 or bigger and they all carry on board air. Next up, a used unit from any semi tractor, Fords airred up fastest. Age, reliability, I drove some trucks with close to a million miles on them, I never had a problem with the air compressor. It takes a lot of air to supply brakes on a 130,000# 8 axlw super bee.

40cfm at 100psi, 100% duty cycle. Bolt on for the F450 etc.

UNDERHOOD® 40 Air Compressors – Trucks

UNDERHOOD® 40 rotary screw air compressors are the perfect solution for service truck operators who use small air tools for light duty work.

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[RAM5500 CAMPERTHING]

I run a dual ARB with (2) 3 gallon tanks to air up my Super Singles (335/80R20)

I had the compressor laying around from a previous build, so i temporarily installed it until i got something bigger/beefier.

I've actually be completely suprised/impressed with how well of a job it does, i replumbed it permanently and will keep it as is.

I find the anti airing down comments hilarious fodder. They are obviously coming from folks that havent driven a vehicle with 7k rated super single tires on a fire road at the recommended pressure!

I dont do it for traction, the truck is a tank and is basically point and shoot. I air down for ride comfort.

I run 55psi all around on the pavement, and 30psi offroad. It is literally night and day with these huge beefcake tires.

As for the "speed" of airing up. No clue, i dont really pay attention, as i am never in a rush to get anywhere.

 

[DirtWhiskey]

Same dilemma as you. I have an MPT 81 super singles. I had been saving up money to do an on-board Sanden style compressor setup on my 2001 f450. But that engine bay is getting more crowded with upgraded steering pump components etc and the $1,800 price tag scares me a little bit. So I sprung on the desert armor 300lpm compressor with their easy air system that allows you to air up and down multiple tires at the same time:

Beast Air Compressor & EZ Air System Bundle

Save some cash and time on the trails with our Beast Air compressor & EZ Air System bundle! Available on backorder!

desertarmorshop.com

So my thought is I'm going to put a 4 to 6 gallon tank somewhere and mount it permanently in one of my underbody boxes. That compressor is a very common model you see on Alibaba but their customer service thus far has been really good. They do some custom components to it and it puts out a lot of air. I'll probably modify it with some sort of fan cooling to increase its duty cycle. One thing to remember is that the mpt-81s don't like to be inflated to 95 psi. Loaded on the road I'm running closer to 60. Should make the air up time a little easier. Also like what somebody said earlier in this thread about getting the tires to 40 or 50 psi and then topping off at a gas station on your way out. Airing down makes a lot of sense especially with a lot of the western back country roads that we drive. Washboards hard hard rocks etc.

 

[danneskjold]

I have a 2004 F450 on 335/80/20 MPT81 and I have probably completed more air up/down cycles than most with just an ARB Twin Air Compressor and it works just fine. Yes, it takes a bit longer than my old 35s but not that much longer. In routinely traveling with others and I don’t feel like they are waiting that much on me.

I’d love a faster compressor but I haven’t really found one (I need to check the links posted above), and the ARB is a really nice size.

I usually run 45/60 (front/rear) highway pressure and drop it to 30/45 or 20/30 off pavement depending on road, duration, and my patience (airing down takes a while too). I’m lazy and use an Indeflate to air down, and I air each tire up manually (no indeflate).

The idea of going from 10–80 PSI seems like a bit of a fantasy to me. If you are following the Continental inflation table then 80 PSI is on a HEAVY truck and I don’t think you would want to take it down anywhere close to that.

Also, I second what @RAM5500 CAMPERTHING said - I don’t air down for traction I do it for comfort. I’ve never had much of an issue with traction.

 

[RoyJ]

For people recommending airing up at a gas station, keep in mind when we're talking about ARB twin, 300L/min, and Oasis / engine driven compressors, most gas station units are SLOWER.

Here's a typical unit:

https://exceltiregauge.com/sc12-ss-air-machine/

If you have an MV50 or low end Viair, it makes sense. But that unit is capped at 80 psi (3.4 - 2.5 CFM), which is barely enough for most medium duty overland trucks.