I didn’t always ride with CO2 cartridges.
I started riding a commuter frame, and packed a medium size pump that has a rudimentary pressure gauge. It is medium size – there are smaller and lighter, and there are bigger without going to a floor pump. But it was too big to go in my back pocket, and the mounting bracket took up the spot that a bottle holder would.
On the recommendation of a bike shop employee, I got a smaller & lighter pump. It fits in my back pocket, and I still pack it to this day. But it was on an evening at dusk that I came to understand how underwhelming the pump was. I was at a local cyclocross event (not a race – no points, no tracking, just fun) when I flatted. Likely the rear wheel, I can’t remember. What I do remember is swapping the tubes while watching numerous mosquitoes feasting on me (blame your parents!). The short stroke of the pump meant that very little volume was being transferred into the tube, and it got more difficult as the pressure in the tube increased. There was also no locking mechanism, so I had to physically maintain the connection on the valve. I got enough air in the tube to ride, barely. It was a squirrelly ride, but luckily a gas station with an air hose was not far.
I promptly the Planet Bike Red Zepplin CO2 inflator. Unlike some inflators, it has two valves that are worked by hand/finger. One is for threading onto the valve stem, while the other valve controls the rate of flow. It’s also incredibly tiny. Controlling the rate of flow is a huge advantage because there are various sizes of CO2 cartridges, so you can blow the tire off if you aren’t careful. The size of the tire also matters – smaller the tire, less CO2 you need to reach a desired tire pressure. There are numerous charts on the internet that provide rough ideas of what tire pressure you can accomplish for the size of cartridge and wheel. Transferring CO2 into the tube can freeze the valve on the valve stem – having a pair of gloves can help if it proves difficult to remove the inflator using bare hands. The Zepplin provides a foam jacket for the CO2 cartridge for when it is too cold to handle, but I haven’t found much need for it. I’ve generally found the Zepplin to make a good seal – I’ve been able to get some CO2 out of a cartridge after months. I can’t promise everyone will have that experience.
What people usually don’t mention about CO2 for inflation is that it is not air (the air we breath is not pure oxygen). That means that the tire will deflate as the gas in the tube transfers out of the tube, into the air. So don’t be surprised if you find a flat tire after a few days. I recommend deflating the tube of CO2 within 24 hours of inflation, to refill with air. Who wants to wonder if they need to patch another tube?
I regularly pack two CO2 cartridges, in addition to a pump. The speed to inflate a tire is good for you, as well as a courtesy to those who are riding with you.