I sure could use some guidance on this project. I have a 1981 Lotus Unique that I am converting to a modern 10-speed drive train. About the only thing I haven't already changed out on the bike is the Crank and bottom bracket (crank or chainrings appear bent/warped by 2-4mm and rubs on FD) . It appears that I have a 68mm BB. The bike was made by tsunoda and I believe that the BB is english threaded. The bearings are inside the BB shell. How limited will I be in selecting a crank and BB? Can i use the newer BB with bearings outlide the shell? Would I even want to? What is compatible with my shell?

Rough measurements put the chainline at about 45mm (so could be 43.5mm) and my Q looks to be about 145. I am putting a 130 rear axle on so not sure what front chainline will be best on the new crank. I usually DIY all my bike work but this is the one area of a bike mechanics that I haven't got my arms around. Any guidance here would sure help. I'd just a s soon not change my Q unless new parts means I have to.

From what I understand I should choose a crank (looking 53/39 172.5 or 175) and use the BB specified provided its compatible with my BB shell. I just don't have a clue what parts are or aren't compatible.