Technical FAQ: Are Shimano external bottom brackets interchangable?

Are Shimano external bottom brackets interchangeable?

Dear Lennard,
I just bought my first new bike in about ten years, and naturally it has a crankset with external bearings, Shimano SLX in this case. Are these Shimano bearing sets interchangeable across component groups? That is, will LX/Ultegra/XTR/Dura-Ace/SLX all work interchangeably? I ask because I would like to have a spare set up bearings and the place I typically buy this stuff only has Ultegra bottom brackets in stock. I’m guessing they would work fine, although they also carry a Chris King bottom bracket set with adjustable and replaceable bearings that is really tempting.

Dear Steve,
Yes, Ultegra or any other Shimano Hollowtech II external bearing set will work fine.

Editor’s Note: This post has since been UPDATED and CORRECTED.