This is all great info, thanks. My freehub body is already pretty chewed up, although it works fine, so not too bothered about it getting worse, although might opt for the wider cog anyway. Junkyard, thanks for the offer – might take you up on it but at work so will email later if I decide I need it. Just one more thing – I intend to use an old Deore steel 32t chainring to kick me off. It is a bit worn, but I have the chain that I was running with it and it was working fine as a triple – no slipping etc. Do you reckon this is likely to be okay, or am I going to lose my knackers through slippage? I haven’t even ridden a singlespeed mtb before, so really unsure what to expect. The simplicity really appeals to me though.
p.s. I take it getting a straight chainline is important?!