bottom bracket upgrade
05-18-08 | 05:08 PM
#1
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Junior Member
Joined: Apr 2008
Posts: 6
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From: Atlanta, GA
Bikes: 1999 KHS Aero Comp, Miyata Fixie
bottom bracket upgrade
Hey all. I'm fixing up an '81ish Miyata and found (not surprisingly) that the original bottom bracket is toast. I'd love to upgrade to a cartridge type sealed bb, but am having a hard time figuring out the correct length for the new one.
Here are the dimensions of the old spindle. It is asymmetrical.
Overall length: 116mm
Drive side (shoulder to tip): 33mm
Middle (shoulder to shoulder): 56mm
Non-drive side (shoulder to tip): 27mm
Are new sealed bb's symmetrical? If so, it seems like the length that I would need is ~122mm (33+56+33). But that seems really long considering it's just a double crank. Anyone have insight?
Here are the dimensions of the old spindle. It is asymmetrical.
Overall length: 116mm
Drive side (shoulder to tip): 33mm
Middle (shoulder to shoulder): 56mm
Non-drive side (shoulder to tip): 27mm
Are new sealed bb's symmetrical? If so, it seems like the length that I would need is ~122mm (33+56+33). But that seems really long considering it's just a double crank. Anyone have insight?
