BB-shell on 1930-50's bikes
 

I was wondering if there were several standards, or if the common ID of the shell was a single size?

When growing up in the 60's, I often came across bikes with the one-piece "Astabula" beach cruiser cranks, and for bicycles today. Now, there are adapters that allow a modern Shimano cartridge to be threaded into a "large shell" BB from a beach cruiser. I just want to know if the old bikes can use these?

http://www.treefortbikes.com/images/raw/CR0500.jpg

Many will fit but be prepared to file some parts, like the bolts. I also found it tricky to cinch the drive side cup because of a lack of tool access. They do work.

Thanks!

...
...I used one in an older Schwinn Super Sport frame that I wanted to update. There were definitely some fitting issues, and the last time I rode it, I think there was a little click starting from some sort of failure to fully seat the adapter cups. So similar experience...be prepared to do some filing. This reminds me I need to take that one apart and reinstall it. :(