I'm old-fashioned about my wheels.

I carry a frame pump, but friends of mine are carrying the CO2 cartridges. I don't carry them, but my reasons are based on anecdotal evidence.

I have heard that CO2:
- can be caustic to rubber.
- CO2 molecules are smaller than "average" air molecules (ok, I know CO2 is much of the air we inhale).

Should I keep up with the times or stay "better safe than sorry"?

Thanks in advance!

Rich

I'm not a chemist, but do some work with materials. I cannot imagine that CO2 would react with tube rubber in an appreciable way. It is a pretty stable molecule. Pure oxygen would potentially do more damage.

Room air is around 78% nitrogen, 21 percent oxygen, and less than 1 percent CO2, H20, argon, and the like, I believe. I don't have a CRC handbook nearby, but I would not suspect that the carbon dioxide molecule would be appreciably larger or smaller than nitrogen (N2) or oxygen (O2). Being a compressed gas, however, the 'yield' from a cartridge will vary depending on the ambient temperature. You might need to warm a bottle to keep it from freezing up on a really chilly day.

I liked the idea of a compact, compressed source. The downside is you only have a finite amount. My solution was to go with the Genuine Innovations MTB Secound Wind, a CO2 unit with handpump option for when testing for tube leaks, initial seating, or backup when cartridges are all used up.

Butyl rubber is much more permeable to CO2 that to air (specifically nitrogen) so a tire filled with CO2 will go flat fairly quickly. CO2 will certainly get you home though.

CO2 will not damage your tubes.

CO2 is pretty inert stuff. It won't eat your tubes but it is rather cold when you fill them. The molecules themselves are rather large compared to the other molecules in air both by molecular weight and by physical size. The CO2 goes through the rubber of the tube by dissolving in the rubber and working its way out. Kind of like trying to hold water in a cardboard box.

CO2 only accounts for 0.038% of our atmosphere. The bulk of the atmosphere is nitrogen with the next highest concentration being oxygen.

I don't do CO2 personally. I figure I have to carry a pump anyway so what good is the cartridge? It is faster but I'm not in that much of a hurry. The pump works, doesn't leave trash that needs to be disposed of, and is always ready.

I don't know sheot from shinola. All I know is that I carry a full size frame pump and several century riders have asked to borrow it after problems with the CO2 evethough they are all experts with those lil canister thingies!

Bad tube, valve, or remaining debris in the tire and you're screwed.

BTW, I used to carry a mini pump for repairs and CO2 for the fill. Found it easier with the full size pump. For a while I carried CO2 along with the fullsize . But none of the riders in trouble ever asked to borrow my CO2. They went straight for the pump!

There is nothing more practical than a full sized frame pump. I've used CO2's for over 10 years and recently decided to go back to traditional methods.