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  1. #1
    mtbr member
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    Sep 2011
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    258

    So, I put the new Dura Ace BB on my Unit...

    I think it looks swell.

    So, this new SM-BB9000 is smaller, to save weight. It has an outside diameter of 39mm, which is the same as my steel BSA BB shell. Another nice thing about the smaller OD is that Shimano provides a reducer "bushing" that fits into your 20 spline external BB tool. The reason it's nice is because the plastic bushing both provides a tighter fit on the BB cups and doesn't mar them. With the standard size, I often put a sheet of plastic over the cup before I put the tool on, to prevent marring.

    Since this is a road BB (68mm shell width), it doesn't come with shell spacers and the sealing tube inside is too short, so you have to use one from a 73mm BB. It's not necessary to have one in, however.

    It was a tight fit with my FSA cranks, I had the bang the crank in with many strikes from a mallet. I bet that Shimano cranks would have a more reasonable fit. Shimano BBs have plastic bushings attached to the inner race of the bearing whereas FSA BBs have the inner race of the bearing directly on the crank spindle. It's an easy, no hammer fit with the 9000 cranks, for what that's worth. I don't have a micrometer to measure cranks.

    I'm gonna take it out tomorrow for a ride and see if it's okay. I mostly bought it for cosmetic reasons, but there should, of course, be top quality bearings and seals inside anyway. That as well as my practically press fit cranks should mean this thing stays rock solid for a long time. I really like the no-BS, constant diameter tube construction of my steel bike, and this makes it look even nicer.
    Attached Thumbnails Attached Thumbnails So, I put the new Dura Ace BB on my Unit...-photo-5.jpg  


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