Technical FAQ: Shimano road and mountain bottom bracket compatibility

  • By Lennard Zinn
  • Published Sep. 9, 2009
  • Updated Nov. 5, 2013 at 5:33 PM EDT

Feedback on last week’s column regarding Shimano Hollowtech II bottom bracket compatibility.

As the note below from Shimano’s Nick Murdick says, I was wrong about Shimano’s external bearing cups all being the same width. I apologize for misleading any of you into trying it.

Hi Lennard,
As a regular reader of your column, I just read the most recent one on and noticed your answer about our BB compatibility. I’m afraid that our road and MTB bottom brackets actually are not the same width. Believe it or not, the road ones are wider. So while one may be able to make it work in a pinch with some custom spacers, I wouldn’t exactly call them interchangeable.
-Nick Murdick
Multi Service Technical Representative
Shimano American Corporation

FILED UNDER: Mountain / MTB / Road / Technical FAQ TAGS: / / / /

Lennard Zinn

Lennard Zinn

Our longtime technical writer joined VeloNews in 1987. He is also a framebuilder, a former U.S. National Team rider, and author of many bicycle books, including Zinn and the Art of Mountain Bike Maintenance and Zinn and the Art of Road Bike Maintenance, as well as Zinn and the Art of Triathlon Bikes and Zinn's Cycling Primer: Maintenance Tips and Skill Building for Cyclists. He holds a Bachelor’s degree in physics from Colorado College. Readers can send brief technical questions to Ask LZ.

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