Nitrogen Test Cartridge instead of CO2?
 

My brother has a lot of these Kidde Nitrogen Test Cartridges from work, and wanted to know if I can use these for inflating my bike tires. I've always used a hand pump, but I do need an air compressor to mount tubeless tires.

I have zero experience with CO2. The cartridge and threaded area look a bit beefier than the CO2 I've seen online, so that alone might rule out it's usage. Also with my understanding, it seems like CO2 is under about 800 PSI and these are 2500 PSI. They look like this www heiserusa com/products/BA120044/

Any thoughts about using these to mount tires?

I believe CO2 is typically stored in a compressed liquid state, while Nitrogen is stored in a compressed gaseous state.

So, while the compressed N2 may work, you get a lot of gas in very little space with the CO2.

It is also possible that your inflation system is not designed to take 2500 PSI. It will have flowing gas, but a pretty high spike in pressure.

I like to experiment some, but I'm not sure that is an experiment I'd choose to do. At least if I was to do it, I'd inspect the system carefully to determine whether it looks like it would blow. And, even so, wear safety gear for the first experiments.

Some people do use pure N2 in tires, but I believe generally filled out of large tanks.

I have no idea if that cartridge would explode your tires from too much high pressure gas or not.

But regarding CO2 vs N2, N2 would be better in your tubes. CO2 often leaks out of tubes quickly, but the tubes are less permeable to N2.

Thanks for the replies. I agree, it does not seem to be worth doing right now, but if any compatible components come my way I will probably give it a try :)

A few years back there was an attempt to sell nitrogen fills for auto tires. I don't recall what the purported benefits were, but it didn't really seem to catch on.

oh, don't worry, the nitrogen filling of tires continues unabated. I'm pretty sure it started because race car teams wanted dry air and nitrogen bottles are really cheap and portable. Then tire places realized they could charge for it, costs $5 a tire or something like that, and you get is a green cap so the next tire place knows they got a live one.

That's correct. If you look at a CO2 tank with a pressure regulator, you would see the tank at around 800PSI for what seems like forever (as you slowly draw down the liquid level). Once the pressure starts to drop, then the liquid is gone.

Other tanks (nitrogen, helium, etc) don't do this. They start at around 3000PSI and gradually drop as you start using the gas.

Tire places hawk nitrogen to drivers because it leaks out of the tire much more slowly than atmospheric air. It's also dry, which is a good thing for tires. Nitrogen-filled tires can go 6+ months with no loss of pressure.

Race cars use nitrogen because it doesn't react nearly as much to changes in temperature. I did tire and suspension setup as part of a short-track pit crew for several years. Tires filled with air could swell by +10psi as the tire heated from ambient to +180º. The same tire filled with nitrogen would only change 1-2psi. Higher pressure changes the rollout of the tire, which changes the stagger of the tires (for circletrack racing, the tires on the left are smaller than the tires on the right) which alters the handling of the car.

I'd love to be able to fill my tires with nitrogen. Dry, leaks out more slowly. No real drawbacks.

The advantage seems minute to only matter for racing teams. For those there also is a safety advantage - in a fiery crash the burning tires wouldn't release oxygen into the fire. But for normal life it wouldn't matter. Air contains 78% nitrogen. If it was true oxygen leaks significantly more, the tire would have an increased nitrogen level after some fill ups.
The scam tire places also don't evacuate the tire first. You go there with a tire and they MAY let the air out to 0 psi (which is 14.7 psi absolute pressure). then fill with nitrogen to 30 psi or whatever you car needs (44.7 psi absolute). so you may have a third air, and 2/3 of nitrogen. they may also only top off your tire, so you may have 79% nitrogen compared to 78%. they also are not likely to use lab grade nitrogen, so maybe you get 95% nitrogen.

So is an inner tube a useful nitrogen purification system?

Fill the tire with air (78% N2). Let the CO2 diffuse out. Top off, etc.

I think I will fill my tires with Ar next time.

It's all moot for bikes anyway-- I found a site selling nitrogen cartridges (same form factor as 12g CO2)-- used to push wine out of casks, and from their text, "Please be aware that the nitrogen will only fill 20% of the space that a 12g CO2 cartridge will because Nitrogen exerts a lower partial pressure than CO2." So a nitrogen cylinder capable of filling even a 700x25 would be like... fist sized.

That is what I was thinking. The tools would have to be designed to deal with the overpressure. But, one would still lack volume into the tire.

I wonder if dry nitrogen would work better with latex sealants than using air. Less oxidizing the stuff while still in the tires.

Exactly this ^^^. The expansion ratio of CO2 going from liquid to gas is 535 to 1. This provides the output of a relatively large volume of pressurized gas from a very small package.

I wonder if it's possible to capture the waste gasses from an oxygen concentrator. They should have significantly less oxygen. Unfortunately, I never see one on CL around here.

An oxygen concentrator could be fun for a number of projects. I guess I never see them on Craigslist because I never look on Craigslist.

Hmmm, a couple are up there now. The best one is probably about 80 miles away. :foo: An awfully long ride. :(

I have never heard of anyone using Argon for tires.

Argon is expensive. Nitrogen is essentially a waste gas.

Nitrogen could be stored in high pressure cylinders, put the expansion ratio would be poor. Nitrogen is almost always transported and stored in liquid form at a relatively low pressure, but it requires very expensive vacuum insulated tanks and even then the heat gain requires the tanks to continually vent waste gas. I you don't use the product quickly enough, a great deal is lost to venting. Liquid nitrogen exists at minus 321 degree F, so it is also dangerous to handle.

https://en.wikipedia.org/wiki/Liquid_nitrogen

Helium-4 should be extremely expensive as a non-renewable resource, but in the USA, it is also treated as a waste gas.

Moisture in the air causes a major portion of the pressure changes. Back when I was working on a CanAm team we tested using compressed air (which was pretty much the standard at the time), dry compressed air, and nitrogen. Nitrogen was the most stable, but dry air was only about 1psi worse over the tire temp range than the nitrogen fill. After some discussion we decided that it would be easier to carry a couple of extra nitrogen bottles (we used them in the pits anyways) and use it to fill the tires rather than adding an air dryer to the compressed air system in the transporter.

G sized nitrogen bottles aren't that expensive from the local welding supply shop. Once you have the regulator it isn't too expensive to keep a bottle around. And if you close the bottle after use it easily lasts a couple of years.

We did the same. A nitrogen cylinder from the welding supply lasted several race days, and gave the added bonus of not having to lug the compressor out to run the impact guns.

Interesting that some moisture in the air in a tire would change the temp/pressure relationship. I am not questioning your experience with race cars and compressed air, but I find it quite interesting that moist air would deviate from ideal gas laws.

Water expands as it gets hotter.

"At 212°F, 14.7 psia, liquid water has a specific volume of 0.016716 ft3/lbm and steam has a specific volume of 26.80 ft3/lbm, which is a volume ratio of ~1600 : 1 of steam:water."

When racing, we had tires running as little as 15psi, and heating to as much as 230º on the center of the carcass. So it doesn't take much moisture inside the tire to cause the pressure to raise at higher temperatures.

Hmmm...

I've wondered about my blowout I had a couple of years ago.

Brand new tire. Filled it up in the evening, say at around 15°C (288K), and by noon it may have been up to 30°C (303K).

It shouldn't have really made that much overall difference in pressure.

I wasn't braking heavily, although the asphalt could have been warm.

But, perhaps a little extra moisture could have contributed to over-pressuring. I likely had a used tube, so not sloshing with water, but perhaps a couple of inflation cycles would have slightly increased the moisture content.

One can dry compressor air. Probably a lot cheaper to simply dry the air than trying to buy N2 tanks.