Originally Posted by
no motor?
I already took the old bearings, the crankarms, and chainrings off. What else would need to come out? The plate for the fixed side that locates everything?
Pictures would help. Is the original a loose-bearing bottom bracket? Then you can't just plop cartridge bearings in there.
I'm with Bob: the cost efficient way to go is just replace the whole bottom bracket with a new Shimano cartridge. New cartridge BB's come complete- all you need to install is the correct tool. Removing the old cup probably requires a different tool, so have the bike shop do it. Once the old BB is out, you'll never need a tool for it again.