How Do CO2 Pumps Work?

If you have ever suffered a flat tire when out for a ride, you will understand the pain of needing to repair a tire or replace an inner tube. One part that is time consuming is inflating the tire, and it seems to take an age, which isn’t great if you get caught out in the cold. Well a CO2 pump is coming to the rescue! But how do CO2 pumps work and why would you get one? Find out more in this guide.

If you want the quick answer:

CO2 pumps by providing a blast of compressed air into your bike tires. You simply screw on the pump, open the valve and your tire inflates. This makes that a great choice for those who want the convenience of being able to inflate their tire quickly if they get caught out when on a ride. However, there are some drawbacks, such as controlling the PSI in the tire.

Want to learn more? Then read on…

How Do CO2 Pumps Work

How Do CO2 Pumps Work?

A CO2 bike pump is a handy tool to have on hand if you are stranded in the middle of nowhere with your bike tires flat. CO2 bike pumps are made by pressing a metal nozzle onto the valve stem to release the air out of the tire. The nozzle will be made up of an area that can be screwed onto the threaded end of a CO2 cartridge that is inserted into the side of the pressure gauge. Once it has been attached, press down and hold for about 10 seconds until the tire is fully inflated. This should allow enough time to get back home before the tire goes completely flat!

One of the downsides of CO2 pumps is that it is difficult to get the tire pressure correct as they don’t have a pressure gauge. This makes CO2 pumps ideal for getting out of an emergency, but not good for long term tire inflation, as you can’t fine-tune the pressure in your tire.

Are CO2 Pumps Any Good?

CO2 bike pumps are a great alternative to hand and foot-operated pumps and can be used on any tire that has a threaded valve stem.

The advantages of CO2 bicycle pumps include:

  • CO2 bike pumps create less pressure than hand and foot-operated bicycle pumps
  • they require little physical labour
  • CO2 gas is stored in an easy to carry cartridge
  • They can be operated without removing the wheel from the bike or inflating tires on a stationary stand.

Disadvantages of CO2 bicycle pumps include:

  • CO2 bicycle pumps do not provide enough airflow to inflate all types of tubeless tires quickly
  • CO2 bicycle pumps don’t have a pressure gauge for measuring the PSI in the tire
  • CO2 bicycle pumps have limited capacity
  • CO2 bicycle pumps cannot be used with non-threaded valves.

How Many Tires Can a CO2 Cartridge Fill?

The efficiency of CO2 cartridge usage will vary depending on the size of tire being filled, but it is possible to fill a standard bike tire with one cartridge. If you have a mountain bike or other larger tires, two cartridges may be needed for filling. The best tip when filling smaller tires is to use a pump to inflate the tire before adding the CO2 which will help speed up the process.

How Many Grams of CO2 Does It Take to Fill a Bike Tire?

In order to fill a road bike tire with enough air to ride home, you will need around 12 grams of CO2. For mountain bike tires, you will need more CO2 and a minimum of 16 grams. Fat bike tires, which are much wider, will take up to 30 grams of CO2 to get full. Unless you want to carry around lots of CO2 cartridges, fat bike riders may be better off buying a fat bike specific pump.

Which Is Better, Presta or Schrader?

Which bike valve is better really depends on the type of bike you are riding and the pressures in your tires. For high-pressure tires, such as road tires, higher pressure is best and therefore you should aim to use Presta valve tires. At lower pressures, the Schrader valves, which are much more affordable, are better.


So there you go. CO2 pumps are pretty easy to use and can get you out of a jam if you get a flat when you’re out for a ride. They’re not ideal as your only pump as it is quite difficult to get the right PSI in your tire when compared to a hand or foot pump.