Hand pumps not quite giving you the inflation you want? A CO2 inflator is a faster, and far easier tool to use - plus they take up less space in your pockets.
They're incredibly simple, as they act as a valve. To use, screw a CO2 canister on one end, screw the other onto your valve and either turn a knob or just press down on a lever and with a short blast of pressurised gas, you're good to go.
Best CO2 inflators you can buy today
➕ Multiple valve types
➕ Well machined
➖ Gas delivery is a bit slow
At just 15g, the Topeak Micro Air Booster is as light as a light thing, but it's also a slimline, well-machined option. The inflator is an inline-style, and it offers modulation depending on how hard you press it into the valve.
The valve head accommodates both Presta and Schrader, and there's a safety spacer which helps keep the storage compact. I found the protective sleeve to be very well insulated against the cold, though a little prone to slipping. It's leak-free, but avoid over-tightening the canister, or it blocks the airflow. Slower flow, but also not that prone to icing.
➕ Easy to read dial
➕ Works as a pressure gauge
➖ Average modulation
➖ Confusing ports
The Topeak Airbooster G2 is by some margin the most chunky option on this list, but it does feature a large, easy-to-read pressure dial. And, if you’re the type of rider who can notice five PSI on either side of your ideal, then this is the one for you.
That being said, I found the three ports (one for canister storage, one for the tyre valve, and one for the gas when in use) a little confusing, and needed the instructions. It comes with a safety spacer, so just use that and store the gas in the live port.
➕ Brilliant sleeve
➕ Leak-free
➖ Lacking modulation
The Birzman Roar protects hands well from the 'freeze' with its sleeve, and has the best coverage of any on test, fits well, and is very well insulated. We really liked the insulated tab that sits over the head, allowing you to press down on the head rather than levering the canister.
The cartridge installation was pretty stiff, but it did mean it was leak-free. Sadly, we did lose some gas at the valve while inflating the tyre. Modulation wasn’t class-leading either, but acceptable compared to inline options like the Micro Airbooster.
➕ Easy modulation
➕ Leak-free
➖ No sleeve
The previous generation Silca Eolo III was a firm favourite, mostly because of the fast inflation, but I appreciate the call for better modulation. It's all too easy to overfill the tyre, then back off too much when letting air out, thus leaving you with a soft ride and no means to inflate.
The Eolo IV takes the same form as the III, but adds a dial, so you can easily control the airflow into the tyre. We found it to be leak-free, but it doesn't come with a sleeve, and Silca has done away with the rubber o-rings of the III too. Given that the inflation takes longer with a dial, I've found it gets very frosty, so definitely one to use with gloves.
➕ Super easy
➕ Rapid
➖ Can overshoot
If simplicity is important, then the Muc-Off CO2 inflator is worth a look. To use, simply screw the canister in (leak-free), screw it onto the valve, then use your thumb on the back of the inflator head to release the gas. The button is plastic-backed, so your thumb won't get stuck as it ices up either.
It is more of an on/off switch than a real modulator, so the gas delivery is incredibly fast, and you can easily overshoot the required PSI. With a bit of practice, you can give really short blasts though, and it makes emptying the rest of the canister a breeze.
➕ Controlled gas flow
➕ No leaks
➖ Hard to empty
We found the Lezyne Trigger Speed Drive to be the most controlled press-to-inflate model of the bunch. There was no leaking at the valve or at the installation of the canister, but the gas delivery was noticeably slower than other press-on options.
I did find that, as it was slow, it iced up a lot and nearly froze onto the valve. You're not going to overshoot easily with this, so press and hold in one go is my advice. Emptying the dregs of the canister was a little tricky too, resulting in more icing up.
Last updated on 16th March 2026 Updated the intro and product descriptions, checked all products were still available for sale and removed any out-of-date or unavailable models.
How to choose
Still a bit unsure as to what you're after? Worry not, I've got you covered. Whether you want to know more about how to use CO2 inflators, or simply aren't quite sure what they are as yet, then scroll down and have a read of my curated FAQ's.
What are CO2 inflators?
,In the basic sense, they're simply a small canister of compressed carbon dioxide that is delivered to your tyre via a valve head. There are variations on the theme, but they all aim to do the same thing. Nearly all use threaded cartridges, so that’s all we’ve featured here, which come in either 16g or 25g varieties.
The two basic types are inline, whereby the cartridge is in line with the valve and actuated by pressing down, and angled types, where the valve head forms a 90-degree angle, and the canister will stick out sideways from the rim when in use. There’s no great difference between the two, but if you’ve got small wheels and lots of spokes, then an angled one might be easier for you to use.
Some just need to be pressed onto the valve to release the CO2, while others have valves to control the flow of gas. The ones without valves tended to over-inflate, but then you just let a bit out from the tyre when you're done. There are a few with special features like gauges.
Many come with a protective sleeve as the Joule-Thomson effect (a change of temperature from the expansion of gases) makes them frost up when in use,
How many cartridges does it take to fill up a tyre?
For road tyres, a single 16g cartridge is sufficient for reinflation and will get it up to and over your desired pressure with ease. You may end up over-inflating and having to back off.
For larger volume tyres, we’re talking gravel bikes here, we’d go for a larger 25g cartridge. While you may have the volume within a 16g for reinflation, you may not be able to reach sufficient pressure to reseat your tubeless tyres, which would leave you in a pickle.
Can I use a CO2 inflator with tubeless tyres?
On the whole, yes. Although some tubeless sealants do say not to. The issue comes with the freezing effect of releasing compressed gas, which can freeze your sealant solid, rendering it useless. The best practice is to rotate the valve to the uppermost point and inflate from there, allowing the liquid sealant to drain to the bottom, as far away from the icy blast as possible.
Fancy trying tubeless? Check out our guide to the best tubeless road tyres.
Are CO2 cartridges single use?
Yes, once they’re installed in the head, they’re basically a disposable item. Once your tyre is back on, you’ll probably want to vent the remainder of the canister by pressing the head against something (not your finger!) or opening the valve. If you unthread the cartridge without doing this, you’ll spray gas everywhere in an uncontrolled way, and if you stow it away without venting the remainder, it could end up venting itself in your jersey pocket.
This also means that for longer rides, you may want to carry a couple of spare cartridges in case the worst happens.
What can I do with the cartridges after use?
They're made of aluminium, so they can be recycled however you currently recycle your aluminium. Please don't leave them on the road or the trailside though.
Does CO2 leak out of bike tyres?
Carbon dioxide is a smaller molecule than the mix of molecules in the air, which normally goes into your tyres. As such, it seeps through the rubber of a tyre more easily and will go flat faster. It won’t go down immediately, but you will notice it the next day. Our advice would be not to rely on CO2 for multi-day events, and if you do have to use a CO2 inflator, then deflate your tyres when you get home and refill from a standard pump.
How we test the best CO2 inflators?
We’ve used plenty of CO2 inflators here at Cyclingnews, so we know what to look for in terms of ease of use, thermal protection, gas delivery modulation and overall build quality.
For this grouptest we used the same tyre each time to avoid any differences in the valve, and always started from totally flat. The tyre in question was a Challenge Strada 27mm, which can be a little tricky to reseat, so it makes an ideal test subject.
