Compressors comparable to Viair 400p

[MilesAndSmiles]

Within the RV community, particularly on YouTube, you'd think that the only reasonable choice for a 12v air compressor is the Viair 400p. It looks like a great unit, but at $200 (more or less) it aught to be! But how do the alternatives hold up? Harbor Freight has a compressor that has comparable specs for $65. I assume there are others.

All I need to do is re-inflate my Class A tires from time to time (95 PSI), and blow out the water hoses once or twice a year when winterizing.

What's worked for you?

[Ed ke6bnl]

I have a  viair for air bags and air horns on the truck. Fory trailer l carry a C02 bottle with a regulator, works great, I like it better than the compressor 

. 

[Kirk W]

Campbell Hausfeld 12-Volt / 12 Air Inflator

[ewacowboy]

We have the Viair....yes it's expensive, but when I need to top off our 125# 5th wheel tires or the 110# steer tires on the truck nothing works better!  Just thought I'd give our experiences.  Good luck in your search.

[jayco1]

Like most tools you rarely regret buying the best. 

[sundancer268]

I have had cheap 12 volt Air Compressor in the past and they worked great for a short time and then quit when I need them.  I now have the VIAIR 450RV and there is no comparison.  I guess I want something I can depend on when I need it.

Edited November 24, 2019 by sundancer268

[TXiceman]

I had two Kobalt 12 volt compressors from Lowe's and both died after a few uses.  Now have a ViAir 400PRV and it is still going over a year later.  You pay your money and take your chances.

Ken

[ALLOY]

 I run 2 - 400C Viair in tandem. This way I have a backup an it was cheaper than buying a better compressor like ARB.

https://arbusa.com/air-compressors/portable-air-compressors/

The 400C get really hot when filling our 17" tires to 120PSI. Don't know how long one would last doing it.

[packnrat]

do you have air brakes on your rv?

you can tap into this source for tons of compressed air. even to change out a tire.

if not then one can not go wrong buying the best, ( buy once, cry only once) but if possible add in a 5 gallon supply tank.

Edited November 25, 2019 by packnrat

[fly2low]

I have an ARB.  Works great

[dmk]

I tried the Harbor Freight one but it didn't work on 22.5 tires and took way longer on the 35's on my JK Wrangler, so I took it back and bought the Viar , way better!

[Carlos]

I have had a Viair 88p for about six years, still going strong.  It is not at all comparable to the 400, but has handled my Jeep tires dozens of times, and the trailer tires a few times.  Probably about $65 at most places.  I added the 6' hose extension for better reach on all tires.

[Ray,IN]

Whatever brand or type you choose to use; remember to buy and use an air filter/dryer on the pressure hose. This is more critical on a small tank compressor, as the compressed air doe not have time to cool and condense air before it enters a tire.

I have a 120VAC Fini pancake compressor with built-in regulator, and always use a small air filter when adding air to tires. That moisture is what causes unusual tire pressure rise at interstate speeds.

[Carlos]

I've never used a filter on the portable and have never noticed any change between its air and the very filtered air I have in my home shop.  I refill the Jeep tires pretty regularly since it's off road a lot.

 

[Ray,IN]

14 minutes ago, Carlos said:

I've never used a filter on the portable and have never noticed any change between its air and the very filtered air I have in my home shop.  I refill the Jeep tires pretty regularly since it's off road a lot.

 

That is your decision, I just presented the facts as I understand them. You will not notice water in compressed air until it condenses, that happens when compressed air(it heats when compressed) temperature  declines to ambient air temperature.

If you are in the SW it is not usually a concern.

Edited December 12, 2019 by Ray,IN

[mptjelgin]

To be clear, the compressed air from one of these inflators will have exactly the same amount of moisture (dewpoint) as the outside air that is being compressed.  The process of compressing the air adds/subtracts nothing. That being said, a filter/drier doesn't hurt a thing, and may reduce the moisture content of the air some under really humid circumstances.

I think that where we see problems on the tank type compressors is when the tank goes for a long period of time without being drained and it accumulates a lot of water. I have drained many cups of water out of park/refuge compressors that obviously hadn't been drained in a long, long time. This amount of water in a tank can introduce a considerable amount of moisture into a tire. It is even a bigger problem if you are trying to paint and get "spits" coming down the line. 

[Kirk W]

28 minutes ago, mptjelgin said:

I have drained many cups of water out of park/refuge compressors that obviously hadn't been drained in a long, long time.

Me too!

[Sehc]

On a humid day in South Jersey my 5 gallon shop compressor will spray water if through a long hose. I run the compressor through a length of copper pipe, then a cheap water separator from HF, then a desiccant filter from NAPA. I use this whenever doing any tire repair or inflating.

[Carlos]

Tank compressors are a different thing from tankless.  I'm not aware of any filter that will remove humidity from a portable tankless compressor without being as big as the compressor and double the cost.  The drier for my plasma torch is big and expensive.

 

[Sehc]

Compressed air is hot. The compressed air contains as much moisture as in the original air it collected. Cool the air and the moisture condenses. We call that water. It doesn't matter what type of air compressor you use. My post was only about my experiences. I'm glad you have a big plasma something or other.

[mptjelgin]

23 minutes ago, Sehc said:

Compressed air is hot. 

Only while or immediately after being compressed. It doesn't stay hot just because it is compressed.

This is where the tank type compressor varies from the tankless.  In a tank-type the air is held at some elevated pressure (say 150 psi). Assuming that it has been there a while it will be a room temperature unless the compressor has been running recently.  But as that 150 psi air comes through the regulator and either into a tire at a lower pressure or into the atmosphere (lower pressure still), it will indeed drop in temperature and may start condensing water, depending on the dew point of the air in the tank. 

With a tankless inflator, the air is compressed, goes through a regulator, and is discharged all in one process.  In that case it is highly unlikely (impossible I think?) to discharge the air at lower temperature than the ambient temperature that it went in at, so condensation shouldn't occur. 

[Sehc]

Time to Go Away. we have successfully hijacked this thread. I guess the water can't get in the tire from direct compressed air. What a engineering break through. good day to you.

[mptjelgin]

1 minute ago, Sehc said:

Time to Go Away. we have successfully hijacked this thread. I guess the water can't get in the tire from direct compressed air. What a engineering break through. good day to you.

Not what I said at all.  Whatever moisture is in the atmosphere goes into the tire. Nothing more, nothing less.

[rickeieio]

23 hours ago, mptjelgin said:

In that case it is highly unlikely (impossible I think?) to discharge the air at lower temperature than the ambient temperature that it went in at, so condensation shouldn't occur. 

Really?  Then how does air conditioning, or a refrigerator work?

You can't re-write the laws of physics, just because you don't understand them.

[Darryl&Rita]

Rick, that's how air conditioning and refrigeration works. The pressure drop causes a temperature drop, resulting in ahh! Cool.