I started carrying CO2 about 9 months ago on my road bike. I've been fortunate in having two flats in that time. Both times, I replaced the tube and used a CO2 cartridge to fill the tube/tire. Both times, the tire was fine two days later but after four days the tire was flat. When I used my floor pump to inflate the tire, everything went well and the tube retained air with very minimal, but normal dissipation over the following weeks.

Am I correct in concluding that CO2 dissipates fairly quickly through the tube and after using a cartridge on the road, the tire should be emptied and refilled with O2 when you get home?

Thanks

CO2 does leak out a lot faster than normal mostly-nitrogen air.
Just keep topping it up and the CO2 will be gone on its own.
I don't think you really meant "O2".

And here's a follow-up question.

As soon as I hit send on this thread, I hear a loud blast and watch one of my tires go flat. I had ridden the bike about 40 miles this morning with no problems and it's been sitting in my living room for the past eight or nine hours. I remember learning about spontaneous combustion about fifty years ago in science class but spontaneous bike flats??? What happened?

Loud bang flats that sound almost like a gunshot are the result of a portion of the tube escaping from the tire and blowing up like a balloon before popping with an explosive sound. Once the tube has popped it's not uncommon for the tire to drop back into place thereby concealing the mechanism of what happened.

One common cause is that a bit of the tube was pinched between the rim wall and the bead of the tire on installation. Frequently it can stay like that for a long time without any apparent problem while riding but gradually it pushes the tire bead up and over the edge of the rim and then you get the explosive flat. Or the tire bead may not have been properly seated on the 'hook' at the edge of the rim. Another less common cause is when the tire has a cut in the sidewall and part of the tube can squeeze out of the cut - but that should be obvious upon examination of the tire.

Take a look at the tube. If its got a big hole or tear, most likely you got part of the tube caught under the bead before inflating it. The tube worked out and exploded.

If you use CO2 to inflate tire, you should replace the CO2 with air as soon as you have access to a floor pump.

Karma!

Seriously, I've had the same happen to me. I had replaced the tires and tubes on a bike I had bought used, and put a few hundred miles on it. I propped it up to take pictures, went inside the house and came back out to find it laying on its side, the front tire blown. The tube had given up along a seam in my case, but the other explanations above are feasible as well for yours.

I'm just glad yours gave out in the living room rather than on the road!

For the original question, yeah, CO2 leaks out quickly. This is yet another reason to check your tire pressure prior to each ride.