Thread: Decipheriing Bottom Bracket Size Code
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Old 09-05-09 | 01:22 PM
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Jeff Wills
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From: other Vancouver
Originally Posted by Steve.D
Thank you BianchiGirl and HillRider. Your comments really helps. I have confirmed that the bottom bracket shell is 68mm long and that the length of the axle is 121.5mm and it is unsymmetrical.

This leads me to another question:

If the axle is unsymmetrical wouldn't I need to somehow specify the unsymmetrical measurements? What do I measure exactly, from end of axle to what? Or is this information coded on the axle?

Here's some pics of the bottom bracket axle I am measuring. It's in great shape but I can't use this particular axle to replacement my warn axle as it belongs to another identical bike.

http://picasaweb.google.com/Cadabyss...eat=directlink

Thanks!
If it's assymmetrical, then the "long" side will always be on the right. This makes clearance for the chainrings. There used to be a lot of variations in BB spindle length, but they're getting hard to find. If you want a cartridge bearing replacement, this YST will work:
http://www.biketoolsetc.com/index.cg...=YS-BB98868122
A half-millimeter change in spindle length is trivial- you may have to adjust the front derailleur a bit when you're finished.
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