Nitrogen vs. CO2?

[Daryl DeArman]

Begining my research on the topic.

What are the initial costs and refill charges?
How long will a bottle last?
What size bottle would be sufficeint?
Is CO2 in race tires worse (moisture content) than "wet" compressed air?

I know that racers utilize nitrogen because it is dry. The off-road crowd (not concerned with pressure build up being predictable) utilize C02, because a smaller bottle can apparently go further (they say the density while in the bottle is much greater). I will not be running any air tools with it. I will utilize it to maintain air pressure in my tires at the track and to fill 4 off road tires on my jeep from 8# to 30# after leaving the trails.

A small air compressor is not the answer. I just returned a small 110v compressor to Lowes as its' performance was pitiful. Fine for the race car a real pain for the jeep. Bringing the compressor from home is also not an option.

Whatever I get must serve double duty.

Thanks.

[carnut169]

I use a small nitrogen bottle (perhaps 4' tall) and it is $6 to fill. That tank will last several weekends or at least 1 including multiple tire flushes where you fill and empty tires to remove moisture. At the SIC I flushed 3 sets and my neighbor did at least 1 set, plus top-offs cart tires, etc. Still have pressure!

[Tico Racing]

I get a full seasson out of the 4' bottle of
Nitrogen. That's around 8 race weekends, filling
one set of tires per weekend, and refilling as
needed.

If you have Fox or Penske dampers Ni makes a lot
more sense than CO2, since you might need the Ni
to top of the canisters. And, as long as you don't
use it for tools, it's very cheap.

Gerry

[R John Lye]

My experience has been the same as Tico Racing's.
I've got a 4' tall N2 bottle, and it has lasted
for a full season (9 races, plus a couple of test
days), and its not empty, but I'll get it refilled
soon anyway. Its useful for both tires and shocks.

John

[Daryl DeArman]

Well, it's cheap and lasts a long time. I hadn't thought about the shock issue. Can't fill those with C02.

So, where can I buy a tank and regulator? Welding supply house? Are any brands of regulators junk?

As long as the tanks last and as cheap as they are to fill I wouldn't mind getting a smaller tank (easier to take on camping trips). Is there a smaller size than the 4' available? Like, maybe the size of a 20# fire extinguisher? Or are those just for SCUBA and Mig welders?

[R John Lye]

I got mine from the local welding supply house. I
just used the regulator that they sold, and its
fine. It might have been cheaper elsewhere but
convenience won out. They can supply various
size tanks, but I can't tell you what all they'll
carry. One thing to watch is to be sure that
the hose you pick will have a burst strength that's
greater than the maximum pressure that you'll be
using (the shocks are fairly high pressure).

John

[TA Treat]

Here's a link to tank sizes. The smallest tank will last quite a while if you shut it off after each use (all hose fittings leak). I just upgraded to the 80 to give me a season of use without worry. tank sizes shown here

The most important item is the regulator. Be sure to get one that can put out the pressure needed for your shocks.

[BrooksHall]

Unless you can remove ALL the air from your tires then Nitrogens advantage is neglegible. I use the Ni for air tools and shox and O2 for my tires. If you are only filling shox then a small bottle is all you need I have a large (5') bottle and it lasts around 3/4 to a full season. The refill was around $25.00.

[DaveW]

The advantage of (dry) N2 is to have as little water as possible inside the tires. If excess moisture is present, it will condense on inner surfaces when things are cool. If you set pressures with this water condensed, and then the tire warms up, this moisture will evaporate and create excess pressure, since the ratio of the volume of water vapor to the volume of liquid water is ~1700-to-1.

The way to get rid of excess water in a tire (introduced by inflating with wet air, using too much tire soap, etc.) is to warm it up in the sun or on the track, bleed it to 0 psi, and then refill with dry air or N2, repeating several times to purge as much water vapor as possible.

I use a small dessicant air dryer to accomplish essentially the same result as using dry N2.

[carnut169]

....and if you do the above, and use new tires on a somewhat regular basis there is no way a 4' tank will last a whole season. Perhaps 2 weekends.

[DaveW]

That's why I use the dessicant dryer - I don't use up the N2 on tires except in an emergency.

[Bill Kincaid]

Aha! I've been looking for some kind of dryer for a while. Dave, what are you using?

[DaveW]

I think this is the one I use. The dessicant in the one I have is reuseable by heating it to dry it out. I also have one replacement quantity of dessicant so I don't run out.
This dryer dessicant will be ruined (coated) by compressor oil, so a water & oil separator filter should be used before the dryer in the air line.

Desiccant Dryer, Total Capacity 600 Cubic Feet, Female NPT Inlet/Outlet 1/4 Inch, Bowl Size 0.25 Pound, Maximum Flow @ 100 PSI 5 SCFM, Height 6 1/2 Inches, Width 3 Inches

Grainger Item #: 5Z610
Price (ea) : $51.55
Manufacturer: WILKERSON
Mfg. Model#: X06-02-000
Catalog 394 Page: 2631

OPTIONAL ACCESSORIES: Description
Replacement Desiccant, 3 Refills, For Use With Dryer Number 5Z610
Price (ea): $25.85 Usually
Grainger Item#: 5Z613


I use it to initially fill tires when I mount them at home, and to replace the wet air when the tire guys mount them. One fill of dessicant lasts for many sets of tires. It is also good for painting so you don't get water in the paint.

[size="1"][ October 31, 2003, 02:47 PM: Message edited by: DaveW ][/size]

[carnut169]

Just out of curiosity... Intercomp has a new tire drying/ purging system they sell for $2400. This is copied from their add:

Tire Drying/Purging System
High performance tire system will vacuum and fill four (4) tires simultaneously through a desiccant monitor. Easy to use toggle lever can set cycle for purging and filling. The desiccant filter can be purchased at an industrial supply shop or the desiccant can be poured on a metal sheet and dried in an oven at 350 degrees for 1 hour.

This system is compact and mounted on a transportable hand cart. System can be removed from the supplied hand cart by removing four bolts and installed in a pit cart or race trailer.

System includes: 4 tire hoses Mercury Vacuum gauge 3 ½ 0-100 tire pressure gauge 150-degree psi input regulator


$2,495.00

102064

and here is a pic...


What the heck is this thing doing that simply running your compressed air through one of Dave's filters doesn't fix? What does 600 cubic feet refer to? (total capacity of what?) Lastly, why not run Nitrogen if you usually mount your tires at home and you don't have to flush?

[DaveW]

I'm guessing, but maybe they mean 600 std cubic ft of 100% humidity air could be dried by this unit, which would mean that you could use it for a minimum of two hours straight (120 minutes x 5 scfm) before the dessicant would need to be refreshed.

[Frank C]

For perspective on sizing, a quick approximate calculation shows about 8 SCF in a set of FF tires. Adding a little extra for the wells in the rims probably puts it around 10 SCF. The dessicant capacity in Dave's unit looks pretty good.
- Frank C