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I just bought a SRAM NX Eagle crankset (DUB standard) for my bike but when it arrived I realised it doesn't fit in the bottom bracket installed on my bike (SM-BB70).

  1. Is there a way to make it work or should I return the product?
  2. If it can be made to work: should I replace the bottom bracket?
  3. If I need to replace the bottom bracket, how can I identify what bottom bracket would be compatible with my bike?

Close-up of bottom bracket showing the "SM-BB70" designation

SRAM crank held beside Shimano bottom bracket, demonstrating lack of fit

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Assuming your shell is either 68 or 73mm, you need the DUB 68/73 ISO (aka threaded aka BSA) bottom bracket. (SRAM calls it BSA instead of ISO, which is psychotic and shows naked and remorseless will to confuse). You need the larger size of the Shimano-pattern outboard BB tools to remove your old BB and the Dub size one for the new BB, which is the same tool as many long-spindle 30mm cranks (Park BBT-79 is an example).

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  • BSC/ISO, yo. Birmingham Small Arms company no longer manufacture bicycles.
    – Noise
    Commented Jul 21, 2021 at 20:40
  • What do you mean by 'Assuming your shell is either 68 or 73mm'? How can I be sure it's a valid assumption?
    – user11696358
    Commented Jul 22, 2021 at 7:31
  • @user11696358 measure it.
    – Nathan Knutson
    Commented Jul 22, 2021 at 8:51
  • yeah sure : ) so 68 or 73mm is the diameter of the shell. I'll check it, thank you
    – user11696358
    Commented Jul 22, 2021 at 9:34
  • @user11696358 Width, not diameter.
    – MaplePanda
    Commented Jul 22, 2021 at 15:13

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