I plan to find/buy an old bike to use as a donor. I think I'll use the head tube, forks, stem (basically the whole front end) from the donor bike to minimise compatibility issues. I'll use the dropouts from a bmx, since I'm building a fixie and it has horizontal dropouts.
Which leaves the bottom bracket. I could buy a new one from a framebuilding supply site or use the one from the donor bike.
- What do I need to consider for the bottom bracket? Should I use a cartridge style bearing and buy some single speed cranks?
- What are the odds that my old donor bike will have a bottom bracket shell that will fit with the new bottom bracket bearings? Do I need to buy a bottom bracket shell from a framebuilding site?
- Are there any other complications I've overlooked?