Portable compressor specs

[windtrader]

Are there specs for a portable compressor that airs up bus and tires in pretty short times? HF has one on rated at 2.2scfm @ 90 psi.

https://www.harborfreight.com/2-gallon-12-hp-135-psi-ultra-quiet-oil-free-professional-air-compressor-64688.html

I have a spare one I was planning to put on the bus but it's a lot less effort to just swipe the CC if it works.

[Iceni John]

That's a 1.2 HP 2-gallon compressor, so I think it would take you a LOOOOONG time to fill a 12R22.5" tire to over 100 PSI.   I have a Harbor Fright 2 HP 4-gallon twin-tank compressor that still barely can fill my tires much over 100 PSI, but it's a useful air source otherwise for tools.   I feed it into the bus's accessories system, and I put a valve to connect that system with the bus's brake system in an emergency  -  it will then air the entire bus to 120 PSI in about 15 minutes!

One significant difference however with mine  -  the advertised one is oil-less, mine is oil-lubricated.   Oil-less compressors are usually noisier than oily ones, run hotter, wear out quicker, and simply won't last as long.   I personally wouldn't buy one of them.

John

[luvrbus]

That one will take time to air a 12r x22.5 up to 100 psi if my memory hasn't failed like other parts of the body it take 5800 cubic inches of air to reach 35 psi my Humvee takes 7500 cu in to reach 40 lbs and it works the on board compressor for long time the more psi the slower the build up with tiny compressors with little tanks.Use your bus compressor it's 12.5 cfm 

[dtcerrato]

Our on board 1 hp 6.4 CFM @ 90 psi airs our entire bus up from zero in five minutes. It feeds into the main compressor discharge muffler so it also cycles through the drier. It is an oiled commercial vintage craftsman unit. Its next to impossible to find a 1 hp 110 VAC compressor in the modern market that produces 6.4 cfm. Times have truly changed. We like old stuff... Must be some pretty heavy busses when talking PSIs to 120. Our 4104 fronts are 90 psi, rears are 75 psi as per specific tire load chart. Those pressures may be a tad higher on our upcoming AK trip - the bus is loaded like the Clampetts! lol

[chessie4905]

Harbor Freight has a recently new model that looks worth the look. Blue tank. Handle removeable, 85db, 150 psi max rated. On sale for $115 . Can't do bad at that price. I'd use it if I didn't already have an old Sears oilless model. Don't discount oilless. Even if Teflon rings wear out, just buy a parent set, since cylinder wall doesn't wear. And you don't have another oil level to check, along with oil in the air supply. My compressor has worked for a lot of hours, and still puts out sufficient air volume. Only problem I had was previous coach owner never drained water from tank. It had a little over 3 gallons in it.

[TomC]

Check out this one from California Air compressors-made here in US not a cheap Chinese model from Harbor Freight. https://www.californiaairtools.com/ultra-quiet-series-of-air-compressor-contractor-grade/2-0-hp-air-compressors/cat-4620ac/ 

[chessie4905]

$306 on Amazon. You can buy 2 from Harbor freight, keep one as a spare if the first one craps out in 10 years.

[Oonrahnjay]

  $306 on Amazon. You can buy 2 from Harbor freight, keep one as a spare if the first one craps out in 10 years. 

     Or 10 days ...  I am SO done with HF ...

[richard5933]

For filling tires, a tank is not really needed. Here is a model from California Air Tools which may fit the bill:

https://www.amazon.com/s?k=tankless+air+compressor&ref=nb_sb_noss_2

It has a 125 psi max, and looks like it will pack pretty neatly into a bay. Guess at 125 psi max it could also be used to fill the air system in the bus at a campground.

Wish I had seen this before buying the one I've got.

[luvrbus]

The Cali compressors really struggle at 100 lbs  mine says it will pump 2 cfm at 90 # that won't happen when it reaches 80# it takes forever to reach 115#, fwiw they have replaced mine twice

[buswarrior]

For those unfamiliar...

The retail marketing of air compressors is a steaming pile...

You want a pump that can pump. That is measured in CFM - cubic feet per minute.

The next important measure is at what pressure it is capable of that CFM rating. Beware, some advertise a CFM at 45 lbs... a poor measure intended to mask a weak compressor... a busnut is more concerned with the more typical CFM at 90 lbs rating.

The HP - horsepower of the motor is next to meaningless and is intended to fool you. Ignore this number, it's intended to distract you. If it has good CfM, by default, it has the motor needed to get there.

Worse, the size of the attached tank doesn't help fill a bus. Tank size only helps in a very small window of pressure recovery, if the unit is being used in short, high volume bursts, again, not a condition a busnut is likely to be in.

Buy the largest CFM number at 90 lbs, that you have the cash for, and you'll be happy.

Defend yourself against the marketers!!!

Happy coaching!
Buswarrior

[luvrbus]

The CA air Tool compressors are assembled in the US not made in the US they have a small place in San Diego with around 15 employees I have been there before,they do run quite with their intake system design .When I stopped by they were doing the Kobalt for Lowes 

[Jim Blackwood]

Compressor noise comes almost entirely from the intake, so it's possible to build a baffled and silenced intake for almost any compressor install.

Almost any compressor can be run from almost any motor. The key is in the reduction of the drive. Old compressors ran slow, had a long stroke, were big and heavy and lasted a long time. New designs are direct drive, have a short stroke, are arguably less efficient, noisy, and the noise they do make is more unpleasant. However they are lighter and cheaper. If space and weight were not a concern the older compressor, biggest one you could get belted up to the motor of your choice at a ratio that won't burn out the motor is a good choice, the limitation being power to drive the motor. But in a bus you don't generally have that luxury so a new direct drive and a good inlet muffler is probably the way to go. CFM rating is one way to pick it. Amperage draw is the other. Don't rely on HP ratings, check the data plate for the motor. Your limitation is how many amps you can supply to it. If the CFM and HP ratings seem unusually high for the current it takes, somebody is lying.

Jim

[chessie4905]

A lot depends on what you are going to use a compressor for. For use to maintain air bag pressure when camping for extended times, these small ones work fine. For inflating tires, why wouldn't you use the one on the coach? Noise? Bury it in the baggage compartment if necessary, or build a hush box.
To save money, buy an old Sears two cylinder belt driven air compressor.up to 3 hp, they use same pump. 5 hp model has a little more displacement. I used a Sears two cylinder pump on an aftermarket 20 gallon tank, oversize pulley, and ran it with a 5 hp 3450 rpm motor. I used this setup for years until I could afford a commercial 5 hp IR compressor, and an Emglo backup 5 hp compressor. Ran air tools, pumped up tires, removed coach lugnuts with a 3/4 drive IR gun. It took longer to catch up after breaking one or two loose, but it worked. I now use that compressor in the car garage for tires, or whatever. Still works great. Just regularily replaced oil with Mobil Rarus 409 or some number. Just find one cheap and go for it.

[RJ]

Don -

That HF compressor you linked to in your initial post is exactly the same one I have in my baggage bay.

I've used it to fill the coach air system from the rear, adjusted tire pressures (both coach and toad), run a couple of air-powered tools, and some other miscellaneous chores.

So far it's done what I wanted it to, and, as a bonus, it's also very quiet, far more so than the one that was in the MCI.

FWIW & HTH. . .