Compressing compressed air

[SuiteSuccess]

I have an air hose which runs off the truck tanks that used to be for trailer brakes (the red knob).  That tank builds to 125-130 psi and will discharge down to 100 psi before the compressor kicks on.  My coach tires need 120 psi for the weight.  I find when I get toward that pressure I have to stop and get the truck compressor to kick back on and get the pressure back up to finish airing.  Air flow stops as the tire pressure becomes higher than the tank pressure.  Maybe a dumb question is there a way to add a permanent auxiliary tank, say 6 gallon (which I already have at home), and compress the compressed air up to say 150-160 psi without breaking the bank?   I once read about a mechanical air pressure booster system to do just that but it was close to$500.

Not trying to limit discussion but I already know I could buy a Viar, or various other portable compressors but that is not the discussion I’m exploring.  I already have a 150 psi pancake that  I use at home.  Just don’t want to lug it on the road.

[noteven]

A check valve between the truck system and the tire tank maybe?

[adept99]

Carl; ol' party pooper here. There just isn't much of a way to do what you are describing. You gotta have something that will squeeze the air to whatever pressure you want. Ultimately, that will be some type of compressor. You can get very high pressures from a very small compressor, but they have virtually no output volume. Consequently, it will take forever to fill your tank. On the other hand, if you use a large compressor, you can fill the tank quickly, but your compressor driver (motor/engine) will run out of power pretty quickly. So how to get from 120 psi to 160 psi? First, make sure your tank and piping (including hoses and fittings) are rated for your highest pressure plus 25%. Then you can decide to upgrade your compressor to one that will make air to the pressure you want. Now, if your existing air tanks and brake cans ever see that pressure, right after you hear a loud "POP", hang on because it will be an exciting ride down the next hill.

Not Really.  It can be done, but it takes a series of valves and connectors and I would be unwilling to have my brakes tied into such a Rube Goldberg setup. I suggest you find a place to mount a small compressor and we can find a way to do a gross fill on that, and then finish with the small compressor. You really don't want to expose the truck compressor to those high pressures, and you REALLY don't want to modify it in any way.

Paul

[HERO Maker]

OK Carl, so your tandem axle trailer is running close to full weight, demanding close to max pressure on those tires?

[HERO Maker]

On my triples, I only use 100lbs.

[Mark and Dale Bruss]

When we were faced with this, we bought a Power Tank, a compressed CO2 tank with a regulator.  It is silent.  We set the regulator to 170 psi for the truck and trailer tires.  You need to be higher to push air into the tires.

For us, a 10 lb tank lasted about a year.

[SuiteSuccess]

Rocky,

First, glad you’re doing well.  Second, yes my weights require higher pressure.  In our older trailer required based on weight was shade over 100 but I added 10% above based on some reading.  New requires 110, hence I run 120.

Mark,

Yeah, I like that system but was hoping I could get some ideas on using my existing and beef it up a bit.  

[SuiteSuccess]

Paul,

As I mentioned there is a mechanical “piston” system that can increase pressures but it is expensive.

[porky69]

Easiest way for pressure and volume would probably be a Power Tank like said above.

 

Power Tank

[Ronbo]

I bought an aluminum co2 tank with a handle. I already had regulator. Fill up trailer tires first and then truck tires. I also use it off road for the Jeep.

[Mark and Dale Bruss]

Using the truck compressors is about as expensive a compressor as you can get and it is not designed for filling tires..  Mine was $700.

[Lance A Lott]

I know you didn't won't to use an electric compressor but if you put a check valve then a T to a 12 volt pump then your quick conector the pump will only come on when you turn it on with a switch. No tank for the electric pump.

[BlueFlame]

Two suggestions. 

Check out this video for an idea on how to cause your compressor to kick in and bring the pressure back up.

http://www.thervgeeks.com/miscellaneous/update-high-pressure-rv-tire-inflation/

-or- Get a scuba tank and first stage regulator.  You can get tanks that hold 80 cubic feet of  air at 3000 psi.  They make tire inflation adapters.  Should be able to top off a lot of tires with one tank, then just stop into any dive shop and get it refilled.

I had the same issue, I need 120 psi on the steer axle, I played around with several methods, got frustrated, finally broke down and bought a Viair compressor.  For me that was the preferred solution.

[SuiteSuccess]

Thanks folks.

Blue Flame,

That is my solution it seems.  At higher pressures I was fanning the brakes to get the compressor to kick in.  Funny how simple solutions evade me sometimes.  Can’t be my age?

[noteven]

Suite - check valve and compressor kicker inner on your trailer supply glad hand is solution. When you was talking about adding a tank I was confused (easy) about just how leaky those 110 psi tires are lol! 

Anyways I only have a few devices that need tires run anywhere near max inflation table psi - a couple motorbikes and a won ton back axle when I throw a load on him. 

Normal air system pressures/cycles do the trick.

[SuiteSuccess]

27 minutes ago, noteven said:

Suite - check valve and compressor kicker inner on your trailer supply glad hand is solution. When you was talking about adding a tank I was confused (easy) about just how leaky those 110 psi tires are lol! 

Anyways I only have a few devices that need tires run anywhere near max inflation table psi - a couple motorbikes and a won ton back axle when I throw a load on him. 

Normal air system pressures/cycles do the trick.

Haha, we’re in the same boat.  I get confused easily.  I was thinking that a second, smaller tank would give me the volume of air at a higher pressure so that I wouldn’t have to air a little bit, go fan the brakes to kick in the compressor and then wait til the truck tank refilled.  At least with the valve I can get the compressor to kick in while at the tire.  The old knees don’t allow me to squat and get up multiple times without paying a price.  Sorry I wasn’t clear.

[wtgeodog]

An expensive solution would be to upgrade tire size to 235 75 r17.5 load range j tires.

 

 

ShortyO

[Ronbo]

5 hours ago, BlueFlame said:

 

-or- Get a scuba tank and first stage regulator.  You can get tanks that hold 80 cubic feet of  air at 3000 psi.  They make tire inflation adapters.  Should be able to top off a lot of tires with one tank, then just stop into any dive shop and get it refilled.

 

Any ethical dive shop won’t fill a tank unless you have a dive card.

[Steve from SoCal]

You CAN increase the air pressure your compressor develops using an intensifier.

https://www.zoro.com/smc-booster-regulator-14-npt-port-vba10a-t02g-z/i/G7277238/feature-product?gclid=Cj0KCQjw3ebdBRC1ARIsAD8U0V7NSsy9kXW5zvfc9HCmGJ1CykP7EF3F1eP-vkR2Qs2NxxzsqtdP_vUaAo8pEALw_wcB

Steve

[DesertMiner]

Oops... that link takes me to vacuum parts.

[MoSKP9]

I have the same issue. Here is my simple low cost solution. Get a combination hand held lever action air fill with gauge that has a 2ft. Extension hose with a  "lock on" air fill chuck. Lock onto valve stem and fill tire while truck is running. You can control air pressure with the lever to let off air rapidly if you have to to keep the truck compressor runnning. You will get the hang of it after a few tries. I'm at the HDT rally right now and if you are also here and want to look at my set up I'll be happy to show it to you .

[SuiteSuccess]

My inelegant solution.  Plugs into air hose and inflation gauge plugs into quick connect.  Ring is “pop off” valve I had lying around.  Pull the ring to decrease pressure below 100 psi where truck compressor kicks in.  That way can get fill pressure back above 120 psi.

Two 1/4” tees, one 1/4” nipple. Rest were supplies I had lying around.  Worked great with my pancake compressor.