Road Bike, Cycling Forums banner
1 - 20 of 85 Posts

·
Registered
Joined
·
87 Posts
Discussion Starter · #1 ·
How much harder would it be to bottle nitrogen instead of CO2 in the air cartridges? CO2 leaks down so fast, why the hell is it the standard?

And onto my hypothetical business idea...how much extra would you pay for nitrogen in a cartridge vs CO2? $1? $2?
 

·
Registered
Joined
·
2,906 Posts
Liquid nitrogen requires dramatically lower temperatures to form. Consequently it costs about 10 times as much, despite making up most of the atmosphere. Also, you know how a CO2 cartridge gets really cold when you vent one to fill a tire? Imagine it getting nearly 300 degrees F colder.


Sent from my iPhone using Tapatalk
 

·
Banned forever.....or not
Joined
·
24,427 Posts
Because the CO2 can be stored in the cartridge in liquid form, at room temperature, under pressure.

(I wasn't quick enough)
 

·
Registered
Joined
·
87 Posts
Discussion Starter · #4 ·
Does it really need to be in liquid form though? Couldn't you just compress it to the same pressure as the CO2 is in the cartridge and get the same inflation power?
 

·
Registered
Joined
·
14,713 Posts
Does it really need to be in liquid form though? Couldn't you just compress it to the same pressure as the CO2 is in the cartridge and get the same inflation power?
To get the same mass of gas, the nitrogen has to be stored at much higher pressure (because it's not liquid), and the container would have to be heavier and more expensive. Some paintball guns use nitrogen (or air) rather than CO2, and the tanks are much more expensive.
 

·
Registered
Joined
·
2,038 Posts
I just use a pump. 80 whacks and I am on the road again. I had a flat yesterday and picked up Two CO2 empties and the remains of a patch kit. Somebody had a hard time there recently and left me with the clean up. I do not mind however as I have been picking up after my 6 kids for years and now with the GrandKids they keep me bending over to pick up stuff. Good for flexibility I suppose.

Anyway CO2 is probably the cheapest and most effective way to produce more litter and to inflate your tire in the absence of a regular pump.
 

·
Registered
Joined
·
87 Posts
Discussion Starter · #9 ·
Leaks down do fast? How fast is "so fast" that's it's a problem for you? Are you doing 24hr rides without access to a hand pump?
Ha, no, but I have noticed that if I flat halfway into a longer ride, its noticeably softer by the end of the ride.
 

·
Banned
Joined
·
3,297 Posts
To get the same mass of gas, the nitrogen has to be stored at much higher pressure (because it's not liquid), and the container would have to be heavier and more expensive. Some paintball guns use nitrogen (or air) rather than CO2, and the tanks are much more expensive.
As the resident physical chemist, I endorse this answer. The only improvement on this I can think to make is a proper subscript: CO[sub]2[/sub] .
 

·
Banned
Joined
·
2,075 Posts
c02, instead of a hand pump, is for Willie's who can't wait to get on the road again.
 

·
Registered
Joined
·
87 Posts
Discussion Starter · #15 ·
To get the same mass of gas, the nitrogen has to be stored at much higher pressure (because it's not liquid), and the container would have to be heavier and more expensive. Some paintball guns use nitrogen (or air) rather than CO2, and the tanks are much more expensive.
Mass is important in paintball because its propelling something. We just have to fill space.

As the resident physical chemist, I endorse this answer. The only improvement on this I can think to make is a proper subscript: CO[sub]2[/sub] .
Does mass/moles really matter though? We're more concerned with the space that it fills. The CO2 cartridge is under ~850 psi pressure...why not put 850psi of nitrogen and not worry about how much it weighs? PV=nRT, the nRT doesn't matter if you're transferring the gas between two vessels at the same temp. P[SUB]1[/SUB]V[SUB]1[/SUB]=P[SUB]2[/SUB]V[SUB]2[/SUB]
 

·
Banned
Joined
·
3,297 Posts
Does mass/moles really matter though? We're more concerned with the space that it fills. The CO2 cartridge is under ~850 psi pressure...why not put 850psi of nitrogen and not worry about how much it weighs? PV=nRT, the nRT doesn't matter if you're transferring the gas between two vessels at the same temp. P[SUB]1[/SUB]V[SUB]1[/SUB]=P[SUB]2[/SUB]V[SUB]2[/SUB]
I think the problem is you are assuming the contents of both of the cylinders are in the gas phase (at least implicitly, in that you are using an ideal gas equation).

In the case of carbon dioxide, you can liquify it under a "reasonable" pressure at room temperature. In the case of nitrogen, you can't liquify it at a "reasonable" pressure at room temperature. So you can jam many more molecules (moles) of CO[sub]2[/sub] into a similarly-sized portable container. Another benefit is that at atmospheric pressure, CO[sub]2[/sub] can't exist as a liquid, so it is less of a hazard to handle than liquid nitrogen (which has an atmospheric boiling point of about 100K).

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

·
Registered
Joined
·
20,789 Posts
50? 60? 70? There's noticeable leak down in 2-3 hours or so.
Did you put a gauge on before and after 2-3hrs?

If you're seeing a noticeable leak down in 2-3hrs, you probably have a bad tube.

I've never had, or heard of, someone having co2 leak down issues in 2-3 hrs. This is such a non-problem. Especially not worth investing in alternate gases or containers.
 

·
Registered
Joined
·
87 Posts
Discussion Starter · #19 ·
I think the problem is you are assuming the contents of both of the cylinders are in the gas phase (at least implicitly, in that you are using an ideal gas equation).

In the case of carbon dioxide, you can liquify it under a "reasonable" pressure at room temperature. In the case of nitrogen, you can't liquify it at a "reasonable" pressure at room temperature. So you can jam many more molecules (moles) of CO[sub]2[/sub] into a similarly-sized portable container. Another benefit is that at atmospheric pressure, CO[sub]2[/sub] can't exist as a liquid, so it is less of a hazard to handle than liquid nitrogen (which has an atmospheric boiling point of about 100K).

https://en.wikipedia.org/wiki/Bottled_gas
But...all that doesn't matter. Until you hit the required pressure, CO2 is a gas, right? Then you keep pumping, then, boom, you get a liquid and you can't put any more CO2 in the bottle, right?

With nitrogen, you keep pumping, keep pumping, and its not going to turn to a liquid. That's fine, as long as you reach a sufficient pressure. You just pump until you get close enough to the limits of the container that you're not wasting space, and far enough that you're not worried about bursting. Hell, you might even be able to achieve a higher pressure than with CO2.

Basically, 1L at 850 psi is going fill the same amount of tires, regardless of what the gas used is, as long as the temperature is constant. Weight and moles may fluctuate, but it doesn't matter in this case.
 

·
Registered
Joined
·
87 Posts
Discussion Starter · #20 ·
Did you put a gauge on before and after 2-3hrs?

If you're seeing a noticeable leak down in 2-3hrs, you probably have a bad tube.

I've never had, or heard of, someone having co2 leak down issues in 2-3 hrs. This is such a non-problem. Especially not worth investing in alternate gases or containers.
Right, so every time I've gotten a flat over the past 12 years and filled it with CO2, I've had a bad tube, but when I use a hand pump I have a good tube? Makes perfect sense.
 
1 - 20 of 85 Posts
Top