Co 2 cartridges

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Anonymous's picture

If I ride a 650 wheel, can I use a 16g CO2 cartridge, or is 12g the max? Is there some standard formula for converting the amount of pressure (PSI) from grams of CO 2? Will my tire explode? Wouldn’t you think that 16g would be for a 700 wheel and 12g for a 650? Am I clueless? (That last part was simply rhetorical and only related t this question.) Where do Mt Bike tires fit into this equation at 80 PSI?

Anonymous's picture
Alan (not verified)
CO2 Cartridges

Look at the Genuine Innovations website ( They have a chart on refill capacity. Basically, a 12g cartridge is intended to fill a road tire to 90psi and a 16g cartridge is intended to fill a road tire to 130psi. I readily admit that I have trouble using cartridges efficiently, and will normally go through two crtridges to fill one road tire to about 90psi. Remember also that you have to remove the CO2 and refill the tube with normal air; the CO2 molecular structure caused it to disperse through the rubber of a tube. In any event, you have to modulate the amount of CO2 that you are putting in to get the right inflation.

Anonymous's picture
steve (not verified)

Just inflate your tire at home using a pump with a gage and get a feel for what 100-120 psi feels like. Then buy the 16g and fill the tube appropriately. Just bleed out the excess.

Anonymous's picture
Colleen (not verified)

I've filled my 650 tires with a 16g CO2 with no problem. Quick and easy, no exploding tire. But, my experience is limited to exactly one flat repair with a cartridge, so take it for what it's worth.

Anonymous's picture
rbj (not verified)

i have been using 12g cartridges for several years and, contrary to what some have said on this board, have had no problems whatsoever - one cartridge to fill a tire, every time, easy as cake. first i let a little air in to make sure the tire is seated, then i open it up all the way and fill the tire in 1 second flat. great time saver. sorry, i have no experience with 650 tires, though.

Anonymous's picture
don montalvo (not verified)
co2 - the old school way

"the old school co2 and effective. it just plain works. back on the road within a minute or two.

first, pull the old tube and look for damage to the tire (glass, slashes, etc.). put a bit of air into the new tube (yep, use your mouth ) so you can insert the tube and ensure the tire bead is seating properly all the way around. the trick at the valve area is to push the valve in so the tire will seat.

now you're ready to inflate...need one 16oz co2 cartridte and one small brass or steel adapter (old style, no moving parts).

the adapter:

this end goes on tube's stem first:

then you twist co2 onto this end:

in less than a second, your tire is full and you're ready to roll. a 16oz co2 cartridge gives my 23c tires 120-130 of pressure. make sure you deflate/reinflate your tire at home (the co2 will leak overnight). the point of co2 is to get you up and rolling again in the quickest amount of time (something your riding buddies will appreciate).


Anonymous's picture
Inga (not verified)
I always use 16g for my 650c tires

"I've done it a million times (thanks to awful Michelin Prorace2 tires, which I have gotten rid of since then, and highly recommend against. They SUCK!). I've never had any problems, and always use 16g to inflate my 650c tires.

I don't put ALL of the CO2 in (I kind of go by ""feel"", compared to my other non-flat tire pressure... One time that I checked, it was actually up to 150psi-yeah, too high... since then I started to put a little less).

I usually put a little CO2 at a time, and then feel the pressure, then put some more, and then repeat... Usually there's a little still left in the cartridge when I am done (so I'm sure 12g would be perfectly fine), but I like having some extra, in case some of the CO2 leaks when I am inflating (which has happened before) the tire."

Anonymous's picture
Bob (not verified)

I use a whole 12g cartridge into 25c ProRace2s. It's just right. (I'm switching over to 28c tires soon and will probably switch over to using 16g carts for them.)

I do not find that you need to replace the CO2 with air - the tire does not leach air any faster with CO2 than pump air.

Anonymous's picture
rbj (not verified)

same here - contrary to what some people say, i do not let the co2 out either; i just leave it in, and maybe after a week i need to top off the tire, which is about what i would do anyway, without co2.

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