Canon versus Nikon, Italy versus France, front wheel drive versus rear wheel drive, Campagnolo versus Shimano, helmet or no helmet? Also in this list is the debate CO2 versus the old fashioned hand pump. It's time to dive a little deeper into it.
Let's start at the beginning. In principle, there is no wrong choice. Both will eventually fill your tire and you can continue cycling. So the "best" choice does not exist. Each system has its own advantages and disadvantages.
Both a CO2 system and a pump cost little space these days.
The hand pump is the most popular system. Pumps have continued to evolve over the years. They have become smaller and lighter. There are now pumps that can be screwed onto the valve using a tube. There are pumps with a pressure gauge and even pumps with bluetooth (from Silca). Very occasionally you will see the old-fashioned Zefal pump clamped under the top tube. As if time has stood still.
In theory, a pump has mostly advantages. You can use it an infinite number of times. It is not harmful to the environment. You only need one per group of cyclists. Flying with it is no problem. At home you don't have to inflate your tire. The lightest pumps weigh less than a CO2 system and are also smaller. A pump is certainly cheaper in the long run. So far, few reasons to choose CO2.
Of course, pumps also have disadvantages. First of all, especially with small pumps it takes quite some effort to actually get the tire pressurized, if at all. Almost all pumps claim to be able to reach 8 bar effortlessly, in practice after a few hundred pumps you're barely at 4 bar. Not ideal. With most pumps you have to do your best to keep the pump on the valve. As said, there are also pumps that work with a tube, but these only work well on valves with a thread. Moreover, when unscrewing them the valve core can come along (been there, done that). Some pumps, although small, are quite long so they won't fit in a small saddlebag. So they either have to be mounted to the frame (which isn't very pretty), or carried in the back pocket. This in turn can turn out to be annoying in case of a crash. Moreover, you run the risk of forgetting the pump.
A CO2 system works with cartridges which, if you search carefully online, you can buy for about 1 euro each. There are two different sizes, the 16 grams for the road bike and the 25 grams for the MTB. Besides a cartridge you also need a pump head. There is quite a difference in pump heads, some of them do not allow you to dose: connecting them means immediately inflating. This is not useful if you want to pre-pump your inner tube to make mounting easier. Or if you want to add some gas on the way.
The big advantage of CO2 is of course its convenience. You screw in the cartridge, put the head on the valve and the tire is full within 1 second. CO2 cartridges are made of aluminum or plastic. Both are therefore harmful to the environment. They can be recycled, although the production and transportation also left a carbon footprint. Those who go for sustainability opt for a pump. Although you can also ask yourself how big the impact on the environment is if you only have a few punctures per season.
As mentioned, a small pump is smaller and lighter than a pump head and 2 cartridges. But a CO2 system is much shorter so it just fits in a small saddlebag. If you choose that option, forgetting is virtually impossible. With a CO2 system, you are limited by the number of cartridges you take with you. If you ride in a group, it is necessary for everyone to bring their own cartridges. If you ride alone, theoretically you could end up with puncture number 3. But everyone knows that such a thing is rather rare (moreover, you will then also have to carry 2 new inner tubes or patches).
To be able to use a CO2 you have to be a little bit handy, if it goes wrong then the cartridge is gone and you have to hope that you have another one with you. But practice makes perfect.
CO2 cartridges used to be banned from airplanes, but that changed in 2019 . One final drawback of a CO2 system is that CO2 escapes pretty quickly through the butyl of your inner tube. That means you'll have to re-inflate the next day, or better yet, deflate the entire tire and re-inflate with your floor pump.
There is no wrong choice. The hand pump has many advantages, but certainly also disadvantages. And the same for CO2. If you want to combine the best of both, there are also hybrid systems; these combine CO2 with a hand pump. But in addition to the advantages, such systems also have their disadvantages: they are anything but small and light.