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  1. #1
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    Bottom Bracket Compatibility Issue...

    Hello. Thanks in advance for reading.

    I'm a complete newbie when it comes to putting together a bike. Needless to say, I'm doing it, and in a big way. Here's my problem.

    I bought a Niner Air 9 Carbon frame which came with a Bio-Centric bottom bracket. I actually thought it WAS the bottom bracket, but it seems that it's just an adjustable component to the bottom bracket shell.

    I also bought a Rotor 3D MTB crankset. It didn't come with a bottom bracket, either.

    I now am faced with research. I've uncovered that there are many differing standards.

    So, my question is: exactly what type of bottom bracket am I looking for? And how do you determine which bottom bracket is ultimately compatible with my setup? With an exact standard, I can figure out which bottom bracket I ultimately will buy.

    Sorry if these questions seem dense. Thanks again for any help!

  2. #2
    Yo.
    Reputation: Slow Eddie's Avatar
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    Rotor does make their own bottom brackets, as you likely know. The BB1 or SABB are the ones that I think are intended to go with the 3D cranks, but any "regular" Shimano-Hollowtech II-type external bearing BB (think Race Face, Enduro, Hope, Chris King, etc. in addition to Shimano) should fit the bill, provided they are for MTB rather than road cranksets.

    HTH.
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    I am a poser. But forums.poser.com doesn't seem to exist, so I come here instead.

  3. #3
    One Gear
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    Enduro As long as you need an entire BB, start with the Enduro. They have great seals and the bearings last a long time. I have 3 different sets all going strong. Don't get the Race Face, they're junk.

    Good luck.

  4. #4
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    Thanks for the replies. Now, how did you know these particular bottom brackets would fit my particular setup? I want to learn so I can figure it all out myself for next time. Thanks again!

  5. #5
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    I like King BB's.

    SPP
    Rigid.

  6. #6
    Riding rigid
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    The Niner Bio-centric is a mechanism used to set the tension should you choose to ride it single speed. Riding with gears, you can also use it to adjust the cranks lower for better stability at the expense of ground clearance or position it up for fewer pedal strikes. Its designed to accept square tapered BBs, ISIS BBs, outboard bearings like Shimano compatible or GXP (Truativ/Avid) BBs.

    3D ought to mention the "type" of BB it is compatible with. Or you can compare the spindle diameter. Shimano compatible are straight 24mm spindles, while GXP have a "step" requiring a different bearing or an adapter.

  7. #7
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    Quote Originally Posted by MTB Pharm View Post
    The Niner Bio-centric is a mechanism used to set the tension should you choose to ride it single speed. Riding with gears, you can also use it to adjust the cranks lower for better stability at the expense of ground clearance or position it up for fewer pedal strikes. Its designed to accept square tapered BBs, ISIS BBs, outboard bearings like Shimano compatible or GXP (Truativ/Avid) BBs.

    3D ought to mention the "type" of BB it is compatible with. Or you can compare the spindle diameter. Shimano compatible are straight 24mm spindles, while GXP have a "step" requiring a different bearing or an adapter.
    Thanks to everyone for the replies. I've really had a lot of trouble nailing down any reliable specs on Rotor's products. Maybe they're on the spanish site and not on the USA one. Hmmm.

    For my Niner frame, I managed to confirm that it has a 73mm BB width with inserts (I presume Biocentric?) installed...and that it's designed for external bearing cranksets only. I suppose this is obvious information for a lot of folks; coming from ground zero, it's almost information overload to try to make sense of the standards, especially when Rotor doesn't make it very easy.

    Rotor's crank (I have the 3D, which is allegedly 24mm, differing from the 3d+ 30mm) is a two-piece design.

    So....I need to buy an external bearing BB which will accept a 24mm spindle, is 73mm wide...anything else?

    I've looked at pictures of external bottom brackets and they have a sleeve which passes through the bottom bracket shell. Does the spindle on my two-piece crank pass through this sleeve? I imagine it must.

    Forgive me if these question sound silly or redundant. I'm trying to be sure before I pull the trigger.

    Thanks again for the help!

  8. #8
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    As slow eddie already said, Shimano compatible BB's will work. They're made for either 68 or 73mm BB shells. Simple Shimano unit is ~$30 from your local shop or slightly cheaper online. CK, Enduro are more expensive (but prob. for a good reason).

  9. #9
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    Quote Originally Posted by phsycle View Post
    As slow eddie already said, Shimano compatible BB's will work. They're made for either 68 or 73mm BB shells. Simple Shimano unit is ~$30 from your local shop or slightly cheaper online. CK, Enduro are more expensive (but prob. for a good reason).
    I appreciate you writing back. However, I'm still not understanding how you know this. Is it just common knowledge? I'm trying to find the measurements that show what I'm actually looking for. In reference to your Shimano note, I went on Sheldon Browns BB page and it's amazing...not one of the hundreds of BBs listed mention the compatibility of the diameter of the spindle. Am I thinking about this all wrong? I sure hope someone can clear it up for me...I'm getting more and more confused.

  10. #10
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    Bottom Bracket Compatibility Issue...

    Quote Originally Posted by Sliphorn View Post
    I appreciate you writing back. However, I'm still not understanding how you know this. Is it just common knowledge? I'm trying to find the measurements that show what I'm actually looking for. In reference to your Shimano note, I went on Sheldon Browns BB page and it's amazing...not one of the hundreds of BBs listed mention the compatibility of the diameter of the spindle. Am I thinking about this all wrong? I sure hope someone can clear it up for me...I'm getting more and more confused.
    Sheldon's BB info is out of date and does not include most current cranksets.

    The Shimano external bearing BB is the type you need. Obvious when you know what to look for. Unfortunately Rotor does not make it easy to find that info.
    mtbtires.com
    The trouble with common sense is it is no longer common

  11. #11
    Riding rigid
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    Your 3D crank install manual

    Quote Originally Posted by Sliphorn View Post
    I appreciate you writing back. However, I'm still not understanding how you know this. Is it just common knowledge? I'm trying to find the measurements that show what I'm actually looking for. In reference to your Shimano note, I went on Sheldon Browns BB page and it's amazing...not one of the hundreds of BBs listed mention the compatibility of the diameter of the spindle. Am I thinking about this all wrong? I sure hope someone can clear it up for me...I'm getting more and more confused.
    The only reference I could find was in the Instructions for the crank install. #1 Bottom bracket install - refer to Rotor SABB or BB1.

    So SABB would be compatible, which is listed as a Shimano compatible BB. with the 73 mm width, you will use 1 of the supplied spacers on the drive side.

  12. #12
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    Isn't it strange how you have to hunt through their PDF literature to figure out any specs? Thanks for the help, guys.

  13. #13
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    And what is this for? Do I need one of these?

    BB30 to 24 mm Bottom Bracket Adapter by Superfly Cycles

    Too much stuff.

  14. #14
    Nouveau Retrogrouch SuperModerator
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    Bottom Bracket Compatibility Issue...

    Quote Originally Posted by Sliphorn View Post
    And what is this for? Do I need one of these?

    BB30 to 24 mm Bottom Bracket Adapter by Superfly Cycles

    Too much stuff.
    No! Just get the Shimano External cup BB and be done with it.
    mtbtires.com
    The trouble with common sense is it is no longer common

  15. #15

  16. #16
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    Quote Originally Posted by shiggy View Post
    No! Just get the Shimano External cup BB and be done with it.
    Okay!

    ^_^

    If anyone else is looking for good info, the post above is excellent.

    Also, look at this:

    The Bottom Bracket (Un) Standard Tree Fort Bikes Blog
    Last edited by Sliphorn; 07-17-2013 at 08:18 PM.

  17. #17
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    After so much reading and research...I've gone and ordered this:

    Hope MTB Bottom Bracket - Steel | Buy Online | ChainReactionCycles.com

    I hope it goes well. Thanks to all for the help!

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