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with inflator, two cartridges and bottle cage:

268g (complete) 178g with inflator and one cartridge 29g bottle cage €39.95 (£35.64 at time of writing)

Want to carry more on your frame, utilising space to keep pack luggage down? The Z2i CO2 Kit is an ingenious bit of gear that may well tick your boxes.


Pros: hydration and inflation in one place, adaptable.


Cons: purchasing a second CO2 adaptor might be handy.



The kit comprises a bottle cage, a slotted bracket (as per the Z2 reversible cage, with additions), to mount the EZ Big Shot CO2 adaptor and cartridge(s) (although ours came without the cartridge cover) – or maybe a pump – all fitting to your trad bottle bosses. So far so good, and even better, you can mix and match the elements, depending on your ride.


Side-entry bottle cages like this are especially useful for smaller or more compact frame geometries, although there’s a lot to be said for them under any circumstance, simply for ease of use. However, the Z2 cage is not strictly side entry, and really small frames may find others a better bet. Good news? The CO2 kit still allows the cage to be reversed, should you wish.

Be aware that not all bottle cages will be compatible.


The bottle cage sits in the bracket, secured to the bosses with your usual bolts. All these are a mixture of composites and reinforced fibre glass. The straps for securing pump or bottle are nylon and silicone.

The additional bracket can take a typical CO2 cartridge on one side, and has its own adaptor. On the other side, the strap can hold another cartridge or a pump, or indeed any suitable, in the 20mm and 32mm diameter holder. There’s more on this below.

zefal co2 kit cage bottle cartridge inflator bicycle tyre tire
bicycle cycle bike inflator casrtridge cage

Held in place by the adaptor, a half-used cartridge could always be swapped to the opposite side, and a second adaptor used to hold the fresh one in place. Mind you, the Big Shot adaptor is small and light, so should fit in any wedge or seat pack. Unlike, say, a semi-empty cartridge attached to the adaptor built into the LifeLine 18in1 Multitool, which might struggle to get into smaller wedge packs.



So long as you have bottle bosses, this is a piece of cake. The big decision is which side to have your bottle, and whether to go for two cartridges or a cartridge and a pump. Personally, I’d go for belt and braces, but that’s because I am often out on group mechanic duties. Your style; your choice.

cartridge mount bottle cage bike bicycle



As a unit the whole comes together very well. It sits solidly together and gives the rider options. Solidarity extends to both pumps and cartridges. Initial fears that cartridge and adaptor would part company proved baseless. You need to ensure the cartridge is screwed in tight enough, needless to say, without piercing it. There’s some vibration, but nothing worth bothering about.

cartridge CO2 bike bicycle cycle cage adaptor

The second mount, for pump or cartridge, is shaped to allow some latitude with diameters. It also has a rubber pad, a further aid to gripping different girths. Zefal suggest a range 20-32mm. So, what has been strapped in and held tightly on road and over gravel? 



The inflator pushes on to Shrader and Presta valves – and , with a little coaxing, I've got air through a Woods/Dunlop, too. Valve contact is very good. A firm push and it grips the valve nicely.

I’ve mounted the kit for road and gravel ventures. The appeal to endure off-roaders and TT speedsters seems pretty clear. Indeed, there are fans of CO2 in many walks of life and cycling disciplines, who might find a place for this.


Value 3.75/5 


Finding direct comparisons is not easy. BBB offer a double cartridge holder which can be combined with a bottle cage for less than six pounds. On the other hand, Topeak’s Tri-Backup Air Station comes in at £12.99. With both, you get the bracket; assemble the rest yourself. It is designed for pump and two 16g CO2 cartridges. Neither guarantee the compatibility of a single coherent system with bottle cage and brackets and all. Paying for convenience may be worthwhile.




Adaptable bit of gear for light-weighters, endure enthusiasts, and other CO2 tendencies. Even if you are not amongst those, you have a decent bottle cage, space for a pump, and can keep the CO2 option, too.

bottle cage pump micro bike bicycle

Verdict: 4/5 Coherent as a system, with plenty of applications.


Steve Dyster




Ryton On Dunsmore

Coventry  CV8 3FH


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