Join Date: Jul 2008
Bikes: Brompton, Dahon Vitesse D5
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Shimano Dura Ace BB 7700 / 7703 differences
I've seen images and descriptions of the 109mm spindle length BB 7700 and it appears to be semi-sealed, i.e. it's an updated version of a cup & cone BB that can be fully dismantled and requires careful cup/locknut adjustment. The cups are connected and sealed with a black plastic middle shell.
I've also seen images of what may be a BB 7703, 118.5mm spindle length, which appears to be a fully-sealed cartridge unit. So I'm wondering if this difference was, for some unknown reason, connected to spindle length, or that there were two different designs pertaining to different years and that the 109mm version also came out as a fully-sealed cartridge BB?