I have a Kona explosif from 1995 that I want/need to convert to 1x9. Need to convert because the left crank is fsck'ed -- the taper is going and the crank does not look like it wants to stay on. The current cranks are Shimano Deore XT, octalink, and the BB is (unsurprisingly) an octalink BB. This far the bike has triple at the front.
Because the crankset needs changing I thought of moving away from octalink and use something that will have more spare parts choice in the future. So, given that:
1\ the BB is a 68mm size
2\ I want a single ring at the front
what spindle length should I get (I might as well get a length that would allow me to mount the chainring outside and not inside the spider at this stage)? Also, I basically know shit about MTBs (I come from road stock) and I was wondering whether I should go for square taper, ISIS or hollowtech. I reckon that hollowtech would make my 'spindle length' question possibly moot, but I would not know how one controls spindle length in a hollowtech system.
Finally, I got a nice 41t chainring, 4 bolts, 104 BCD, so if you feel like recommending cranks compatible with the ring (and the BB!) do feel free -- I'm all ears.
Budget: I'd like no more than 100 quid, but I can stretch it to 120 ish.