OK then, I now have my Topeak CO2bra CO2 Inflator, and if you get one you’ll find there’s a slight disparity between what the instruction sheet says and what you have in your hand.
To remove it from its card you need scissors or nail clippers to cut the cable tie holding it and – you’ll just love this bit of dumb-arsery – a spanner and Allen (hex), key to unbolt the accompanying cycle mount from the packaging! (Actually, it turned out to be just possible to get sufficient grip on the nuts with my fingertips – but an Allen key you will need.)
First, the safety ring will probably be in its socket on the body of the inflator (you slip this over the business end of a full cartridge to stop it being accidentally pierced in transit. In its place you’ll find a steel washer, which can be removed and stashed in your bits box (never discard washers, or bolts and nuts – one day they’ll come in handy.
The other thing is that the protective sleeve doesn’t grip the cartridge well when screwing it home (or at all, really), so slip it off and wear a glove, or something to protect your hand. You don’t actually need it, the cartridge will get cold but the discharge of gas as it’s connected is so brief it won’t freeze your skin the way it does in use. I still recommend protection, though. That way you can’t blame/sue me if it all goes a bit pear-shaped and you get frostbite!
So, having pierced the cartridge, slip the cover back on – you’ll need it. Now flip up the grey lever. It’s VERY stiff and if, like me, you have grip problems, you might want to use a 2p coin to help – just push it under the lever and it’ll pop up. Otherwise, if your thumb slips, it could cost you a nail. It might be a nuisance for some of us, but it prevents accidental discharge in transit.
To operate, screw the connector onto the valve stem (the connector is threaded for both Schrader
and Presta **), and push the lever up with your thumb – the movement is quite short and, like others I’ve used, gas flow is all or nothing, no finesse at all.
**Er, no, it’s not – Presta is push-on, only Schrader is threaded, which kinda sucks.
And that’s it.
If you want to attach the bike mount to your chair, this comes with fittings for the centre-line bosses/holes on a bike, and also a pair of rubber protectors and a couple of cable ties for attachment to undrilled tubes. Use these – do not drill holes in your (possibly), horribly expensive chair! Not only might it weaken a vital frame member, it might well make it hard to sell at a later date.
I suggest putting it on one of the footrest hangers where you can reach it easily, and, of course, see that you haven’t gone out without it if you use it at home (I use a track pump at home – takes seconds even from flat, and even for someone as knackered as me – electric pumps, none I can afford, at least, just won’t reach the desired pressure). And do make sure you carry a handful of spare cartridges – one per tyre might suffice for my skinny tyres to get me moving again, maybe one and a bit to give me the pressure I actually want. More for those of you with fatter tyres.
I’m also about to order a pair of rubber reducers to convert my rims from Schrader fitting to Presta, as the latter valves are less prone to leakage, being positively sealed by means of a screw-down collar, whereas Schrader depend on a small spring and, mainly, air pressure to maintain the seal.