Bicycle Mechanics - plastic left bottom bracket cup - square taper

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TurbineBlade
09-22-11, 07:28 PM
Hey - if my bike has a 68mm width bottom bracket, will any plastic left side cup work? I broke one and need to find another ;).

Thanks

desertdork
09-22-11, 08:57 PM
Since the crack typically occurs during a moment of overzealous tightening, can we assume that the cup and the BB cartridge are currently installed in the frame? If so, have you considered just riding it as is? You may find that the crack doesn't have a negative impact on the function of the BB.

Problem Solvers makes the UP-CUP#54 aluminum left cup. I see it described as specifically for UN54 cup replacement, but perhaps it has other applications as well. A bit pricey @ $20, though.
oldbobcat
09-22-11, 08:59 PM
Yeah, if the threading is the same you shouldn't have a problem. It's not a cup, anyway, it functions as a retainer for the left side of the cartridge. Use plenty of grease on the threads and inner contact surface to facilitate insertion.