By Carl on Sunday, October 14, 2001 - 10:06 am: Edit

In some basic searching I see several options for getting air back in tires. ARB, and other 12v pump options 200-$300, CO2 tanks which are supposedly much faster, yet need refilling after 7-10 uses? Both options need mounting of yet another weight adding thing.

What is considered "the best"??

thanks for your thoughts.

By Collin on Sunday, October 14, 2001 - 10:31 am: Edit

Carl,

I recently purchased a 12v pump from 4x4 Connection (www.4x4connection.com) to air up my tires. I bought the kit which came with the "BIG RED" pump, 25' recoiling hose, tire valve clip(so you don't have to stand there and hold the nozzle on the stem), and a .50 caliber ammo can to store everything in. It clips onto the battery and aired up all of my tires from 30 to 50 psi in a bout four minutes each. It's quick. I should tell you though that the pump did have to rest between the 3rd and 4th tire four about 5 minutes. I am going to put a massive heat sink on the top of it so this doesn't happen again. The whole thing is rather compact. I had considered something like "Trail Air," but didn't want to bother with having the tank refilled. Hope this helps.

Collin

By Scott Tschantz (Scott) on Sunday, October 14, 2001 - 01:53 pm: Edit

Carl I have seen a big red pump in action on the trail and a power tank and a Trail Air and the Co2 tanks win hands down All four tires aired back up in a few minutes vs 1 tire and a waiting
period for the pump to cool down Especialy if you run a large tire. Also I have seen a tire bead re seated with the use of a trail air system . Not to mention being able to run air tools and as far as re filling my local welding supply shop will fill a 10 lb tank for a few dollars

Just my experiance Scott

By Mike D1 on Sunday, October 14, 2001 - 04:39 pm: Edit

I have the ARB pump for my lockers. I have the kit to fill tires and it takes a long time and gets very hot. The ARB is made for lockers and works well for that. I am going to get a tank. Any welding shop can sell you a tank and fill it. Check the price of welding shop vs. Trail Air for the tank and valve.

By Mike B. on Sunday, October 14, 2001 - 05:38 pm: Edit

I have the PowerTank. It is the best, but costs more than the Trail Air. The valve allows you to adjust the pressure up and down to suit your needs (from 0 to 160 lbs). Most other products set the pressure at a fixed rate.

I bought the dual tank system, so when one tank runs out I just switch to the other. You can get it refilled for about $10.00 at any welding supply shop. One tank has lasted me all summer (3 months). I've run power tools and aired up my tires at least 11 times. I still have 800 lbs of pressure in the tank. If you are looking for the ultimate, this is the way to go.

Thanks,
Mike B.

By Greg Davis on Monday, October 15, 2001 - 11:26 am: Edit

I purchased a used 10# CO2 tank for $20, went to my local Welder's Supply and paid $46 for a regulator (adjsutable), and spent $22 for air hose and fitting to air up tires. Heavier than PowerTank, but a helluva lot less expensive. Not as pretty, either. :-)

By peter matusov on Monday, October 15, 2001 - 01:56 pm: Edit

Carl,

I bought my 20# welding CO2 tank with regulator at the swap meet for $90, and +$14 for hose and accessories. It blows all the pumps I've seen. No problem seating a bead on a 33x12.5 tire with all the dirt and mud on the rim. It won't run air tools for long, but no pump (except for a mongo industrial-type) will be able to do it at all. The 20lb tank is ways overkill, I didn't know that they come as small as 2lb. Normally, a 2lb tank will air you up after 2-3 trips. I charge my tank ($16 a charge) about once in 3-4 months, and I wheel rather often, and my friends use it as well.

peter

By RVR OVR (Tom) on Monday, October 15, 2001 - 11:20 pm: Edit

Well, you can "roll your own". However, you get what you pay for. The ones you will buy from most welders will typically be heavier (steel vs. aluminum) and the regulators are going to be huge by comparison. Also, the Trail-Air regulator goes up to 300 psi and is adjustable.

Finally, Trail-Air has the mounts dirt cheap that work perfectly with their tanks.

Tom

By p m on Tuesday, October 16, 2001 - 02:27 pm: Edit

Tom,

i may be off the base here, but all welding CO2 tanks in 2-20lb size I've ever seen were aluminum.

there's no excuse for TrailAir charging 300 bucks for a 10-lb tank.

also, every welding supply store has mounts for the tanks, not that dirt cheap, but very well made.

peter

By Kyle on Tuesday, October 16, 2001 - 02:29 pm: Edit

And regulators can be bought that are pretty small as well... The small migs use them...


Kyle

By Greg Davis on Tuesday, October 16, 2001 - 03:03 pm: Edit

Tom, I've got a 10# CO2 tank that's steel. Heavy as hell. Would love an aluminum one.

By joe casey on Tuesday, October 16, 2001 - 03:07 pm: Edit

peter,

power tank is the one who sells the tanks for 300. trail air sells aluminum ones for about 130-150 for the 10 and 20 lb tanks.

Joe Casey

By p m on Tuesday, October 16, 2001 - 03:11 pm: Edit

oh, that's right. I recall trail air - they paint a large logo on a regular welding tank (as opposed to powertank's polish or black paint job).
I remember thinking of this source as a good blow to powertank.

but even that is overpriced!

peter

By Roverine on Tuesday, October 16, 2001 - 03:25 pm: Edit

Glad to see this thread today - I've been thinking about a tank as well (darn .. I hate being sensible ... I want lights, suspension, etc., etc.) Something modest, but that gets the job done quickly (quick being the key word for me), and easy to mount/carry. (At this time, I don't think it would see a lot of frequent use - maybe once a month or so ...) Also, where & how do you guys safely carry them? Sorry if I'm bringing up a redundant subject ...

Kim

By badams on Tuesday, October 16, 2001 - 04:36 pm: Edit

I am going to "roll my own" system using a 10# alum. tank. I will post pictures and information when I get around to it.

By Dean Brown (Deanbrown3d) on Tuesday, October 16, 2001 - 04:42 pm: Edit

The guy at my welding house seemed a bit of a oddball. He first said that you should go for compressed nitrogen, in a steel cylinder that weighs 20 lb. BUT, it has 2000psi and has a volume of say one half a cubic foot, which (I think) translates to 20 cu ft at 50psi, right? Is this enough? A tire is what one or two cu ft? Maybe not so bad.

Then he said that the CO2 that comes out the cylinder is contaminated with petroleum vapors, that would be harmful to the tire and make it last 5000 miles less. But I thought the only wore out from the outside!?

(I thought that CO2 came from the beer industry - fermentation)

Oh well, just thought I'd let you know.
Dean

By Dean Brown (Deanbrown3d) on Tuesday, October 16, 2001 - 04:45 pm: Edit

Of course, if it did come from fermentation, then we would indirectly be funding the beer business

By p m on Tuesday, October 16, 2001 - 04:59 pm: Edit

Kim,

if you took a chance of looking in the back of my rangie last Sat., you'd have seen the tank in question. big tank, 40lbs when full. cheap, too.

peter

By Dean Brown (Deanbrown3d) on Tuesday, October 16, 2001 - 05:07 pm: Edit

Anyone know where to get a good deal on an aly cylinder (10 lbs)?

By p m on Tuesday, October 16, 2001 - 05:07 pm: Edit

Dean,

that sounds a bit of BS about petroleum contamination.
The most important is that CO2 is liquid at a room temperature, at a pressure of about 1200psi, give or take a couple of hundred depending on temp.
Therefore, it contains much more gas than any compressed gas tank would, at a lower pressure. There has been a discussion about how and whether it is safe to haul the tank around on many off-road lists; guess the fact that PowerTank and TrailAir are marketing these, it should be pretty safe.

Aluminum (from which the tanks are made) is ductile, and it does not send shrapnel all over the place if it blows. I've seen a photo of what happened to a car where a 5 lb CO2 tank exploded - not pretty, but not like a car bomb. Still, the guys in the welding supply shop (where the photo was hung on the wall) did not have any explanation or info on why have it happened.

back to the number of tires inflated issue - 10lb PowerTank is said to be able to inflate up to 40 33x12.5 tires from 15 to 35 psi. Based on my intervals of recharging the 20lb tank, it is a close estimate; i occasionally run air tools off this tank, which takes a LOT of CO2 out of it. But it is sure nice to be able to undo the rover lug nuts with an air wrench!

peter

By Murray (Cdnrvr) on Tuesday, October 16, 2001 - 05:12 pm: Edit

Hands down the Trail-Air is the best bang for your buck. For me, by the time I ran around, picked up everything and fabricated it, I figured out I wasn't much further ahead. Tom's stuff is good quality and he provides great service.

Murray

By Dean Brown (Deanbrown3d) on Tuesday, October 16, 2001 - 05:23 pm: Edit

Peter,

yes, of course its complete bullshit (i just needed someone else to confirm it!)

Really,
10 lb of CO2
= 4.5kg
= 100 moles (RMM = 44g)
= 100 * 22.4 L @ 1 atm (15 psi)
= 2240L @ 15 psi
at 1L = 0.264 cu ft this is:
= 590 cu ft @ 15 psi
= 180 cu ft @ 50 psi

compared to:

8 L tank (as above) @ 2000psi nitrogen: (btw it couldn't hold that pressure)
= 320L @ 50psi
= 85 cu ft @ 50 psi

So, the CO2 is more than double the gas volume, and has a constant high pressure (unlike the N2 that runs downs when used and needs a stronger cylinder to start with.

Dean (chem background)

By p m on Tuesday, October 16, 2001 - 05:59 pm: Edit

that's some excellent piece of work, Dean

there's very similar relationship between LPG and compressed gas - the outcome is that you win anytime when you can keep the stuff liquid under normal conditions.


peter

By p m on Tuesday, October 16, 2001 - 06:03 pm: Edit

maybe, except for 1 liter being 0.0277 of a cu.ft.
which puts the 10lb CO2 tank at about 19cu.ft. at 50psi, a bit closer to the PowerTank's "40 tires from 15 to 35 psi" claim.

peter

By RVR OVR (Tom) on Tuesday, October 16, 2001 - 06:05 pm: Edit

By the way, that is not me that Murray was referring to. A different Tom sells the tanks.

By the way, like Murray said, you can go hunting and buy the stuff and save some bucks or you can buy the Trail Air ready to go and tested with a nice mount that works in the Disco. All the prices on the site include shipping and everything is brand new. A used anything will always be cheaper.

In any case, CO2 is a better option than nitrogen. From the trail-air site:

"So why not use Nitrogen instead of CO2??? Nitrogen has such a high tank pressure. About 3000lb vs. CO2
which is around 750. This makes CO2 much safer to handle than Nitrogen.
There is less Nitrogen capacity for the same size tank. The CO2 tank is filled w/ liquid that expands as it's depressurized
which allows for more volume. The nitrogen is straight gas, this means less volume."

From the powertank site:
"CO2 will give you three times the energy of Nitrogen in a given tank size. Having one tank of CO2 is like carrying three tanks of nitrogen. This makes it more economical and means that you'll have the power when you need it all in one small tank."

One benefit to nitrogen, however, is that it can be mounted on it's side. CO2 tanks always have to be standing up.

Tom

By p m on Tuesday, October 16, 2001 - 06:14 pm: Edit

CO2 tank doesn't have to be standing up. It needs to be upright for a few minutes when you air up your tires or otherwise use it.

liquid CO2 pressure at ~70F (last time i checked was yesterday) is about 1200 psi. If your gauge shows 750 psi, the tank is empty.

peter

By Roverine on Tuesday, October 16, 2001 - 07:01 pm: Edit

This may be a dumb question, but what about traveling with a CO2 tank in heat, high altitudes, etc.? Any special precautions?

Kim

By p m on Tuesday, October 16, 2001 - 07:32 pm: Edit

Kim,

don't know how high is high and how hot is hot -
on this trip to truckhaven it was fairly warm; the tank took many more trips at 100F+ temps, and up to 8500ft. in elevation.

Guess the elevation issue is moot - in the total vacuum, the pressure difference between inside and outside of the tank would be 15 psi more than at the sea level (say, 1215psi vs. 1200psi).

and yeah, i've dropped the full tank from the tailgate's height a couple of times

this is not to say that the tank will be okay no matter what; but, if you need a source of compressed air (or, better yet, chemically inert gas) on the trail or in the garage, CO2 tanks can hardly be beat by anything.

peter

By Dean Brown (Deanbrown3d) on Tuesday, October 16, 2001 - 09:25 pm: Edit

Peter,

sorry, you're right, I had the number for Liters per galon. (However, Liters per cu ft = 0.035).

However, the SAME factor was used in BOTH calculations, so the relative amounts are identical still.

Dean

By Dean Brown (Deanbrown3d) on Tuesday, October 16, 2001 - 09:30 pm: Edit

Kim,

These cylinders are commercial cylinders, manhandled every day and left in the sun on the hottest days of the year on the back of a truck. They also have safety devices built in to release the pressure in case of a fire.

To cut down on leaks and temperatures, a polished silver one might be slightly better.

The MOST dangerous thing is knocking it over and breaking off the main valve - then you have a rocket. Hence, never remove the pretective handle up top.

Dean

By Roverine on Tuesday, October 16, 2001 - 09:31 pm: Edit

Thanks Peter,

We used to have a bunch of scuba tanks around our garage, but I dunno anything about the CO2's (I suspect Greg may ...)

Kim

By Dean Brown (Deanbrown3d) on Tuesday, October 16, 2001 - 09:34 pm: Edit

That reminded me of when I was a student - I was using fluorine gas (easliy the most reactive know element) in a cylinder 5 feet tall and 12 inches diameter, filled with 2000psi. The valve was corroded shut, so we had to hammer it with a giant wooden club every time we used it. Not something that would normally be considered sensible!

It is said that if it explodes, the F2 gas gets your vocal chords first - and then nobody hears you scream!

Dean

By Dean Brown (Deanbrown3d) on Tuesday, October 16, 2001 - 09:40 pm: Edit

Kim,

Just ask the welding shop. It might also say on the tank how much pressure it can take.

Dean

By p m on Tuesday, October 16, 2001 - 10:08 pm: Edit

damn, 0.0353 all right
0.0283 is how much of a cubic meter is a cu.ft.
0.0277 came right from nowhere.

hehehe

but you're right again, it doesn't matter when you compare liters to liters.

i think it said something like 3500 psi on the tank, will double-check tonight.

peter

By jay caragay (Jcaragay) on Wednesday, October 17, 2001 - 12:13 am: Edit

I just would like to add some comments about CO2 and Nitrogen. I used to be a very avid Paintball player several years back so I have a bit of experience with both CO2 and Nitrogen and their use in wilderness conditions.

CO2 is a pretty stable gas. High temperatures are a consideration but it is unlikely the tank would explode due to the expansion of the liquid CO2. On a typical tank, there is a rated burst disc on the valve that would blow and dissipate the gas before it could pressurize to the point of rupturing the tank. A similar burst disc can be found on Nitrogen tanks as well.

Both CO2 and Nitrogen can be stored upright, horizontal or upside down and they can even be used in such positions. The peril of using an upside down or horizontal CO2 tank for the application of tire fills is that it would feed liquid CO2 directly and likely cause the tire to rupture - not the ideal situation.

All tanks must be pressure tested every five years by a certified facility that will stamp the tank in question upon passing. Ensuring that your tank is properly tested and certified is paramount to the structural integrity of the tank, not to mention your own life. Outside of that, the biggest concern when using pressurized gas is the accidental shearing off of the tank valve or a drop from a considerable height. I've seen what happens when the careless broke the valve on a 9oz CO2 tank as it shot across the room and mangled one of those old style steel with green vinyl office chairs - unbelieveable. I shudder to think of the damage a 20lb tank would cause.

Dropping the tank from a considerable height with enough force is also another consideration. A 20lb CO2 dropped in a manner that would cause it to rupture and explode would unleash the power of a 500lb bomb. So, dropping the tank from the top of your Adventure Rack in Moab is not a good idea.

By Ho Chung (Ho) on Wednesday, October 17, 2001 - 11:10 am: Edit

you guys scare me more than the CO2 tank. LOL

By p m on Wednesday, October 17, 2001 - 12:10 pm: Edit

hehehe....

I'd say an Adventure rack is the last place where i'd want my 20lb CO2 tank to be

actually, if you're in Moab for a few days, you don't even need to air up (if you aired down), the highway mileage will be next to none So, i'd gladly take a 2- or 5-lb CO2 bottle and keep it inside.

peter