I recently picked up a 1984 Trek 620 touring bike that saw very little miles. We just completed a 100-mile weekender tour and I've decided I need to upgrade the drivetrain. It is being ridden by my wife who is not the most adaptable to mechanical quirks.
Primary problem experienced by my wife is the shifting (which is mechanically fine and has a brand new chain). The crank is a Shimano N600 touring with 28/45/50 rings. 5-speed rear with downtube friction.
a) The 28t -> 45t -> 28t jump is huge. I think it is clunky, difficult, and prone to dropping the chain. Seems like a really weird combo.
b) would prefer at least indexed shifting for the rear.
At this point I'm considering these options:
Option 1: Ditch everything (but keep 27" rims**), Bar-end shifters
-- front crank replacement: Sugino XD-350 (28-36-48)
-- rebuild rear (27") wheel with new Shimano LX freehub. Assume spreading 126mm frame to 130mm hub is ok?
-- DA bar-con shifters w/ 9-speed cassette
-- Deore rear derailleur.
Option 2: Bare essentials, indexed down-tube shifters
-- if possible, replace the 45t cog with something like a 40t cog?? Advice on what to get?
-- find indexed rear shifter, possibly upgrading from the current 5-speed to a 7-speed freewheel cassette?? Rear spacing is 126mm. Possible? Do I need to redish wheel?
-- Keep everything else-- derailleurs, hubs.
Any advice appreciated.
** not really considering 700cc conversion. I tried mounting 700cc wheels, and while the cantis reach with adjustment, I think they are mechanically disadvantaged. Only reason I would want to upgrade is to get fenders in there given the ridiculous 1/4" of spacing available between the front tire and fork crown.