It's really quiet at work today so I thought I'd post this on here instead.
My brother in law isn't a particularly keen cyclist but commutes to work. He uses a very old mountain bike and says he never changes gear anyway so was wondering if he could convert it to SS.
I have told him it's probably relatively easy and I'd help him but I don't actually know how to do it!
Do I need a new rear SS-specific wheel?
I've no idea what his rear dropouts look like - I'm guessing I should find out?
What else do we need to buy?
ta.
depends how old/low rent it is.
If it has a freehub like most modern mtb's then you can get a kit including tensioner, cog and spacers and fit those.
tbh, if he never changes gear, it all works and he's happy with it I'd leave well alone...
The minimalbodge is to take a single cog from a cassette and (assuming freehub not freewheel) space that out using old cassette spacers or cut chunks of waste pipe so it aligns with middle or outer ring at the front. Take the rings you're not using off (might need short chainring bolts, or maybe some washers to bodge it.
If he's got horizontal drop outs, which are forward facing and a bit sloping (ie not track ends - rear facing and actually horizontal) then he might have enough play to tension the chain (shortened as needed). If vertical dropouts (or not enough adjustment) then you can use the mech as a tensioner - cut a length of cable inner from the shifter end and feed that into your dérailleur so the barrel stop buts up against the cable outer stop (hope fully with an cable tension adjuster). Then clamp the cable up with the mech roughly in line with the cog and tweak it with the adjuster. You might also be able to do this with the hi-lo stop adjusters.
That's how to do it without buying anything else. Generally it works better with ss specific cogs and rings which don't have shifting ramps, so they'd be the first thing to buy if needed, plus a new chain (cheap 8spd usually works well). And then you could buy a ss tensioner to replace the mech bodge.
http://www.charliethebikemonger.com/one-speed-kits-216-c.asp
or cheaper:
http://www.on-one.co.uk/i/q/SKOOSSKK/on-one-singlespeed-converter-kit
put longer screws in the mech and set the limit stops so it fits the single ring only. COnsider shortening the chain and running it only through the upper jockey