B’Twin CO2 Inflator and 16g Cartridge

The BTwin CO2 Inflator & 16g Cartridge Set is probably the best-value inflator on the market. At £8, fitting 16 or 25g canisters with precisely-controllable one-handed inflation, it's a great buy.

With the head threaded most of the way onto the cartridge it's 12cm long, and easily slips into a pocket. Removed from the cartridge it's as small as these things get, so easily put into a tool roll.

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It's hard to imagine a simpler process: screw on the canister fully, press onto valve – done. In reality, the pressing down onto the valve will push it through the rim if you've removed the threaded ring from your valve stem, or are running unthreaded valves. Either way, applying pressure opposite onto the tyre to keep the valve in place is dead easy, and as the tube starts to inflate, the valve very quickly resumes its natural position and pushes back against the inflator head.

If you have your thumb against the tyre then it's intuitive to gauge how much CO2 has flowed in – more so, I believe, than more upmarket inflators with on-off knobs, where you are not pressing against the tyre as a matter of course.

The fact that the head is angled is a bonus over those where the cartridge is set at 90 degrees to the valve – you need to push down with a less-aligned force in that instance, making gauging how hard to press and for how long less intuitive.

On the first inflation I managed to get it spot on the 50psi I was aiming for with a 28mm front wheel – the most accurate I've ever managed to be with an inflator, I think. On the second shot at an empty 28mm tyre I managed to get 30psi before it was completely empty – which roughly aligns with the maths on grams-of-CO2-per-psi.

> Check out our guide to the best pumps and CO2 inflators

The metal head is very cold to touch, so I imagine emptying the entire cartridge in one go would be borderline painful if you weren't wearing gloves or using a bit of fabric – a sleeve, snood or casquette maybe. Because you want to have your forefinger and thumb either side of the head to control pressure I'd say such lengths are recommended – you can use it by holding the plastic insulated sleeve, but the control afforded is not as nuanced.

The plastic sleeve and rubber band that slips around the canister is minimalist but does the job, and will take 16 or 20g cartridges.

All in all, for eight quid including a 16g canister, it's a great buy.

Verdict

It's as small as these things get, works intuitively and gives fine control. For eight quid, it's a cracker