I mainly use my road bike during the triathlon season and now that the season is coming back around again, I am finding some old, unused CO2 cartridges from last season (fall).

I typically use 16 gram CO2 cartridges and they usually fill my bike to about 90 psi.

Are these cartridges still safe to use after months of inactivity?

I've tried researching the matter online but all I've read applies to airsoft, etc. and not necessarily the 16g bicycling cartridges I'm concerned about. But, from what I did read CO2 cartridges have a chance of leaking if not stored correcty and may indeed have a shelf life.

  • 4
    If they don't have a use-by date printed on them you can pretty much guarantee that they'll keep for many years, (e.g. batteries). If they'd only keep a year or so they'd need sufficient information for stock control at the retailer.
    – Chris H
    May 26, 2015 at 8:34

3 Answers 3


They last pretty much forever provided they haven't been damaged (e.g. punctured or rusted or something), so go ahead and use them.

If you really want to check them, you can buy a few new ones and weigh them on a scale (and compare the weights of the old cartridges to the new ones). If they're significantly lighter, they've leaked and throw them out. Else, go ahead and use them. But a few years (say less than a decade) is pretty much nothing in terms of having issues with the cartridges leaking.

  • I am not sure if weighing them really makes a lot of sense. I would guess that the weight of the gas is negligible compared to the weight of the container itself? (I didn't calculate)
    – Bernhard
    Jul 5, 2015 at 9:55
  • If you have a scale that resolves in grams, you should be able to measure it , as I've approximately discussed in this answer, as the amount of air in a tire is on the order of grams. Carbon dioxide has a molar mass of 44 g/mol, and its the number of mols which determine the pressure, so the weights in that answer will be underestimates. The key thing is that you need a reference for how much an unused cartridge weighs beforehand. Or better, just don't worry and use them
    – Batman
    Jul 5, 2015 at 11:31
  • 1
    The variance in weight in an empty cartridge should be pretty well controlled in manufacturing. In any case, for that to be the problem, the variance needs to be quite high.
    – Batman
    Jul 5, 2015 at 13:21
  • 2
    I happen to have an empty and a full of the same brand of 16g CO2 cartridge and a kitchen scale. I got 42 grams for the empty and 57 grams for the full.
    – freiheit
    Aug 3, 2015 at 2:26
  • 9
    Indeed, one would expect about 16 grams difference between a full and empty 16 gram cartridge. =)
    – Batman
    Aug 3, 2015 at 2:38

Yesterday I was out biking and got a flat. My CO2 canisters are many years old, I’m going to guess about 5 to 10 years old. When I went to fill up the flat absolutely no aire came out. The canister was undamaged and any visible way. In hindsight was quite light. So yeah after many years your CO2 canisters can apparently totally let you down. I was calling for ride. It makes sense. PHI extinguishers for example do lose pressure over years and this is why they are inspected and expire. Believe it or not air molecules can move through the metal wall just happens at a very slow rate. In fact that’s the principle by which your bike tire loses pressure overtime. And easily seen in a birthday balloon On a short time scale


I inherited a Crossman pellet pistol from my father along with some cartridges .They were about 20 years old when I tried to use them.They worked but only had power for a few shots. Another 20 years later I tried again. This time They did not have enough for even one shot. SO..They last a long time but Not Forever

  • 3
    The o-rings in the pellet gun are most probably dry rotted and the pressure change is likely lube-less. Did you compare against recently store bought cartridges?
    – RoboKaren
    May 9, 2018 at 14:20

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