ak08820

How many uses do the CO2 cartriges give?
E.g., if you are on the road and had a flat and just replace the tube with a good one and inflate with a cartridge. How many such tubes could a catridge inflate?
Let us assume it is a MTB and we do 40 PSI or so.

10 Wheels

Catridges come in three sizes, 12,16, and 40 grams.
Tires and tubes come in many sizes.

Depends.

HillRider

Typically a CO2 cartridge is good for one use in one tire. The most common sizes are 12 and 16 grams and will fill a 700x23 road tire to ~90-130 psi and a typical MTB tire to 40-50 psi. One and you're done.

ThermionicScott 

40 psi is pretty easy to get with a hand pump...

jim hughes

The reason I've never used cartridges is that there's no way to tell what's left in them. Therefor I 'd have to discard them after one use, or carry more than one.

WickedThump

I keep one in the inflator and carry two spares.

JTGraphics

1 full charge some may be left in i but its usless at that point.

HillRider

As I said, they are one use items. You empty them as much as possible into the tube and discard the empty cylinder. And, yes, I carry three. I found that a mini-pump plus 3 12-gm cartridges weigh a bit less than a full size frame pump and are more convenient.

I fill the new tube to 20-30 psi with the pump to be sure the tube is good and the tire seated properly. Then the CO2 cylinder completes the fill to about 100 psi in a couple of seconds with no danger to the valve stem from 200+ pump strokes.

Bianchigirll 

I agree. 40 is pretty low and IMHO CO2 with clicnhers can cause more problems than they are worth. You need to be real carefull that the tube is not caught under the bead of the tire, as it could get pinched when the CO2 is discharged. Had it happen a few times.

FBinNY 

Most CO2 systems do not allow you to effectively reuse the remaining gas in a cartridge. They're a use once and discard item. There are systems that allow you to meter the flow and stop half way, but they tend to slowly leak over time, so you cannot rely on that half empty cartridge you're saving.

CO2 is fine for small tires such as 700x25c where one cartridge can fill a tire to decent pressure. But on larger tires they won't and you have three choices.

1- use the CO2 for the immediate emergency, and ride home on the partly filled tire

2- use the CO2, and top off with a pump. This is a poor approach since the CO2 did the easy part, and you're left trying to do the hardest part of the job, which if you could, you might as well have skipped on the CO2 altogether.

3- pre-fill the tire part way with your pump, and use the CO2 to finish the job. The right amount of pre-fill depends on the size of the tire, cartridge and desired final pressure. You can estimate the amount by using one cartridge to fill an empty tire, and noting the pressure achieved. Subtract this form ideal pressure to get the amount of pre-fill pressure needed.

IMO, pre-fill and top off is the smartest way to use CO2. It allows you to confirm seating and centering before using the one-shot unit, and gets you to full riding pressure without serious pumping effort.

ak08820

Great answers, the summary, as I gathered is that for most ordinary adapters, it is one cartridge per inflation. I think it is better to carry a small a pump as it is economical in the long run.

JTGraphics

I actually use a 2nd Wind Road - Carbon Mini it's both CO2 tire inflation along with high pressure hand pump all in one.
I will use the hand pump to check seating before I top off with CO2. So I do not need to carry a separate hand pump with me for insurance if CO2 should fail but so far CO2 has done me well.
Also if you do use CO2 on the road to get you going again when you get home deflate the tire and pump it back up with your floor pump or compressor CO2 gas does not last and your tire will be flat in a day or two if you leave it in.

Capecodder

Start and seat the tire with a hand pump, and finish with CO2..... It's the best way.

DiabloScott

After I use a cart, I leave it in the holder - there's still gas in there of course. So when I get my next flat, I...

1. Install the new tube
2. Empty the old cart into the newly installed tube
3. Put a new cart in my inflator
4. Finish pressurizing the new tube with the new cart
5. Leave the new cart in the inflator for next time.

This gives higher pressure and eliminates the need for a mini pump.

Capecodder

The mini pump is to slowly start to inflate the tire, and seat the bead correctly as to not pinch the tube, then blast it with CO2 to finish it off.

DiabloScott

Right, and you can use a mostly spent CO2 cart to do the same thing. See Step 2

rogerwaggener

What about the spent cartridges?
Everybody recycles them, right? Right?

Chief

Short answer.... one use.

HillRider

You don't use CO2 for the economy, you use it for the convenience and speed. A typical mini pump will require 200+ strokes to reach 80-90 psi in a 700x23 tire and the last 100 strokes will require some real force as the pressure goes up. This not only take a lot of time and effort, you are at increasing risk of snapping the valve stem unless you are careful to support the pump head.

Unthreaded 12gm CO2 cartridges are $.50 each or less in boxes of 15 or 25 at any Wal-Mart so the cost of this convenience is very small unless you get daily flats.

dramiscram

Same. Once the cartridge is perforated it will slow leak in few hours so defently one shot.

WickedThump

The threaded 16g cartidges can be found on Amazon for a lot less than the LBS charges:
https://www.amazon.com/Each-Gram-Thre...9027303&sr=8-6

HillRider

Yeah, that's a pretty good price at only $1 each. More than 12 gm unthreaded ones but not nearly as bad as the LBS price.

redlude97

Or partially fill the tube with your mouth and then fill with CO2, no pinch flats and you don't need to carry a mini pump

HillRider

Ever blow into a pressure gauge? About the best you can do is 2-3 psi.

fietsbob

JRA they're silly.. just to not carry a pump.. timed races maybe..