How to Choose the Best Bicycle CO2 Pump
Bike Tire Inflators Using Compressed Air Carbon Dioxide Cartridges
Aug 29, 2009
CO2 pumps are powerful and portable: small and light. Driven by single-use carbon dioxide (CO2) cartridges, they can re-inflate a tire in seconds.
CO2 inflators aren't expensive, with some selling for $10. Popular brands include Genuine Innovations, Topeak and Nashbar. These manufacturers also make combination mini hand pump and CO2 hybrid pumps.
Cartridges can range from less than a dollar to a few dollars, depending on type and capacity. Popular capacities are 12 and 16 grams.
Threaded Versus Unthreaded CO2 Cartridges
Threaded cartridges have a screw thread on the neck, allowing for a secure screw-on seal with the pump. They are more expensive than unthreaded (threadless) cartridges.
Threaded cartridges can jam more easily than unthreaded cartridges. The released CO2 cools as it expands, sometimes freezing the threads of the cartridge and pump together.
Some cyclists warn against using the cheaper 12 gram unthreaded cartridges made for air guns (BB, Airsoft, paintball), claiming that lubricant in the cartridges can slowly weaken the rubber of tire inner tubes.
Nozzle-only Versus Full Body CO2 Pumps
For long distance cyclists, every ounce counts. Minimalist pumps consisting of only the nozzle head are the lightest pumps around. Most can use both 12 and 16 gram threaded cartridges.
Advantage
- Small and light.
Disadvantages
- Can't use unthreaded cartridges.
- Exposed cartridge becomes cold during use and can be difficult to handle.
Useful features
- Insulated sleeve for the cartridge.
- Metal construction. Plastic heads can break, especially if the cartridge thread is jammed.
- Rotating-knob or trigger-pull gas release control. Simpler pumps are controlled by rotating the cartridge, which can be difficult. To stop inflation with these simple pumps, the cartridge is completely unscrewed, allowing the remaining gas to escape. This wastes unused cartridge capacity. Two-step inflation is sometimes useful when fixing a flat tire.
Full body pumps encase the cartridge in a plastic shell.
Advantages
- Both threaded and unthreaded cartridges can be used.
- Easy control of gas release with a rotating-knob or trigger-pull control.
Disadvantage
- Slightly heavier.
Useful features
- Support for both 12 and 16 gram unthreaded cartridges. Most support both 12 and 16 gram threaded cartridges. Support for unthreaded cartridges is more limited: some support only 12 or 16 gram unthreaded cartridges, not both.
- Metal construction. Plastic heads can break, especially if the cartridge thread is jammed.
CO2 Pump Limitations
CO2 pumps are best used with a tire repair kit as an emergency on-the-road tire inflator, an alternative to a manual hand pump (frame pump or mini pump). Because of the expense of replacement cartridges, they are not suitable for regular use.
Unlike other types of pumps, few CO2 pumps have built-in pressure gauges. For exact inflation, a separate pressure gauge is needed. For emergency use, approximate pressure is enough. Squeezing the sides of the tire can give a rough pressure estimate.
Enough spare cartridges to fully inflate at least two tires and/or a hand pump should be carried. If too few cartridges are carried, the cyclist who encounters another cyclist with a flat tire has two unattractive options (it is worse if they are traveling together):
- Ignoring the unfortunate cyclist.
- Using up the cartridges and leaving none for himself, a dangerous situation if he develops a flat later.
A cyclist could also develop more than one flat on his own bicycle, on one trip.
Cyclists who are unfamiliar with the advantages and disadvantages of CO2 pumps should read this comparison of different bicycle pump types.
It should be noted that many airlines prohibit CO2 cartridges from being brought onboard the aircraft, even in checked luggage.
The Best CO2 Bicycle Pump
A reliable pump is an important part of any emergency bicycle repair kit. The best CO2 pump has a full body cartridge case, can use threaded and unthreaded cartridges, and has a metal head.
As with other types of emergency equipment, the pump should be tested beforehand. Fully deflating the tire and reinflating it:
- Allows the cyclist to practice controlling the release of gas.
- Gives an estimate of the number of cartridges required.
- Tests the durability of the pump.
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