Originally Posted by
himespau
Finally (for tonight anyway), I was planning on replacing the bb with a cartridge bb that I have laying around. If the shell is 68 mm, it should be english thread and any 68 mm english thread shimano un-55 should work, right?
Check the shell. It might be 70mm (and english thread). If so, I've had luck with Shimano cartridge BB's by replacing the NDS cup with one from a mtb BB. The cups are labeled 68 or 73 and are externally identical but engage the cartridge at different depths internally (if that makes any sense). If it's a 68mm shell the UN-55 will fit the BB shell but the chainline and chainstay clearance, etc will depend what crankset is used.