After struggling for hours with an awkward rim and tyre combo I decided to make my own ghetto tubeless inflator out of an empty coke bottle. This did the trick of seating my tyres however I thought I could do better and I thought I'd share with you guys how I did it.
Please note that fire extinguishers are pressurised and therefore this could be considered dangerous but you all know that. If proper care and attention is taken then this can be done safely however I take no responsibility for any damage or injuries that may result from following my instructions.
Here is what you need:
A 1 Kg powder fire extinguisher. I bought mine for just under £12 from eurocarparts.com as they were the cheapest at the time.
6mm ID hose. Cost me about £2 from ebay.
Various drill bits
A zip tie.
Firstly you need to discharge the fire extinguisher. How you do this is up to you. I emptied mine into a dustbin as the powder can make quite a mess. Be careful not to breathe in the powder as it's probably not going to be good for you.
Once you have fully discharged the extinguisher you can remove the head. I managed this fairly easily by hand. Once removed from your bottle you should be left with this:
On one side of the head you have a pressure guage and on the other you have a pressure release valve. This valve will allow the gas to escape at a pre-set pressure so the extinguisher won't explode in the event of a fire. We are going to remove this and modify it to fit a presta valve.
Start by unthreading the nut as shown:
You can ditch the spring and seal. Now you need to open out the hole to 6-6.5mm. I used a 6mm drill bit but it was a bit tight getting the valve through. In hindsight the 6.5mm bit would have been easier.
I needed to modify an old presta valve to fit. Trim the outside of the rubber until it fits inside the thread as shown.
Now assemble the valve into the nut you opened out to 6.5mm. I used a tiny bit of tubeless sealant to ensure a good seal however this isn't really that necessary.
Now when I first made this it was hard to pump up as the air was too restricted. I opened out the internal holes in the head itself with a 4.5mm drill bit. Firstly you need to further disassemble the plastic internal parts. You can ditch the central tube as this is isn't needed. Be careful not to drill too deep as you may damage the pressure gauge and / or break through the head meaning you'll never manage to seal it. This was fairly easy as that material was quite soft. It should look something like this once done:
Now it's time to put everything back together. On the nozzle on the head I managed to squeeze on some 6mm ID tubing. You'll need to use your zip tie here to ensure it doesn't fly off under pressure and maybe some araldite or similar would help to ensure that this doesn't happen in use.
I used a hand pump for the initial testing. 14 bar (the working pressure of the extinguisher) equates to roughly 200psi so if your gauge is half way there you should be at around 100psi. Obviously using a track pump with a gauge will let you now exactly how much pressure you have. In practice around 70psi seems to seat my tyres no problem however you could go higher if desired. I wouldn't however recommend going up to 14 bar!
And there you go! One tubeless inflator that took me about half an hour to make that is robust and durable. Mine even came with a wall mount so it'll be going up in the shed shortly.
One thing to note is that this still looks like a fire extinguisher. For safety reasons I would recommend painting it or modifying it in some way that clearly makes it distinguishable from a real extinguisher. You can do this however you please. I'll probably wrap mine in some funky gaffer tape or something like that.
I hope that this guide is of use to some of you. Any questions pop a comment and I'll try and answer as best I can.