So we talked in an earlier post about CO2 cartridges -- what they are and why you would use them. But did you know that CO2 cartridges come in different sizes? They do, and that means a real difference in how much inflation you get.
In small batches, CO2 cartridges can cost $5 each in the bike shop, or maybe three for $10 if you're lucky. So I was comparison shopping and found a 15-pack of 12-gram CO2 cartridges for $.50 each at Wal-Mart. You can get larger 16 gram cartridges for about $1.00 each in bulk online in cases of 25 or more. Yes, that's twice as much cost per cartridge for just four grams more of gas in each.
Huh. Four grams of CO2 doesn't seem like a lot of difference but in the end, it is enough to push the choice to the 16g cartridge. Here's the deal... though a fellow rider insists that you have to use two cartridges regardless of size (12g or 16g) to fill a standard skinny 700x23 road bike tire, I don't agree. I've never had to use more than one 16g cartridge to reinflate after a flat. And so if you do have to use two 12g cartridges to fill a tire vs one 16g, that's no savings in the end, either in cost or in extra weight you're carrying.
Any opinion on this? Comment below. I'm especially curious if you've noticed any practical difference in filling ability between a 12g and 16g CO2 cartridge.
Or, what about your thoughts on using CO2 cartridges at all: are they more helpful or just another nuisance gadget?
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Comments
I’ve used the 16 gram and it was not enough to fill a 700×23 tube but with that being said I used the non-threaded cartridge and it was hard to use without half of the gas escaping. I am going to switch to the threaded cartridge and see if that works better.
There are charts out there that show how many psi the different sizes CO2 will fill to. like in the 700/23 a 12gram will fill up to 90 psi. the 16 gram will fill up to 130 psi.
Be careful with the cheaper CO2 cartridges. They’re designed for use in air rifles and paintball guns… they have traces of oil which will eventually destroy tubes. Only use cartridges designed for inflating tires.
I’ve only used one 12 gram on my 700 X 23. I carry cartridges for emergencies only and one gets me up to 90 psi. This is enough to carry on and get me home. I also carry a schrader to presta adapter as a back up, which can be used at any filling station.
According to the charts, you can fill a 700×23 up to 90 psi with a 12g CO2 cartridge, and up to 130 psi with a 16g cartridge. Your actual results may vary, depending on the type of adapter you use, and how well you’ve honed your technique. I can typically get my 700×23’s up to 110-120 psi with a single 16g cartridge – and I throttle it in several stages while filling, inspecting to ensure everything seats properly.
Most 700×23’s will still be very susceptible to pinch flats at less than 100 psi, so why fill to 90 or less with a 12g cartridge and leave yourself vulnerable to yet another repair on your way home? Get the 16g cartridges and do it right the first time! And don’t forget to later deflate that tire completely and refill it with regular air, or it will be flat again in a matter of days, since CO2 leaks out much more quickly than air.