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  1. #1
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    bottom bracket sizing + single chainring

    I have a 2009 GTR Series 4

    Since I'm not using my smaller chainring, I decided to remove it and leave the larger chainring to shed some weigh via small chainring, front deraileur and shifters.

    I already switched out my rear wheel w/ a ultegra 9-speed cassette and a dura-ace 7700 9speed shifters.



    Now I'm switching my crankset to dura-ace 7700 also.

    I am going to remove the small chainring and leave the large one also, and in order to keep a decent chainline...i'm going to take the large chainring and put it on the inner side where the smaller ring was.

    Here's the question since I am only running a single chainring in the front and a 9speed in the back.

    What size length bottom bracket should I be using?

  2. #2
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    I have seen only two sizes for those BBs.. 109 and 118

    The triple uses 118...

  3. #3
    Real Men Ride Ordinaries fuzz2050's Avatar
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    Chances are you won't have the clearance to run the big chain ring on the inside. It will likely rub against the chain stays. You might be able to run it on the outside, but just use a shorter bottom bracket, moving it inwards just slightly. It would probably get you a better chain line anyway.

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