I love biking, but I'm really no mechanic. I currently have a Shimano M6100 groupset (Deore) with me. A friend is going to give me a good deal on a carbon MTB frame, but I'm worried about compatability, particularly the bottom bracket (BB-MT500-PA). The frame specs describes it as "PF 30 bottom bracket" and "46*73 mm" with the Greek fie or phi symbol in between. Would that work or fit?

enter image description here

  • For reference, the phi symbol means “diameter”. It’s supposed to be a perfect circle with a line through it, but I presume that the phi symbol is less obscure. It should be ⌀ – MaplePanda Jan 11 at 2:05

Bottom bracket standards are numerous and confusing. Have a look at https://wheelsmfg.com/bb-standards. That's the best online resource I have found so far that explains them.

PF30 bottom brackets are designed for a 30mm crank axle. Shimano cranks have a 24mm axle. What you need is a bottom bracket that adapts between the PF30 specification frame and the Shimano crank. An example is https://wheelsmfg.com/pressfit-30-to-outboard-bottom-bracket-for-24mm-cranks-shimano-black.html. Other manufacturers make similar products.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.