Bicycle Mechanics - What kind of BB do I have?
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08-19-11, 05:22 PM
I have two older Japanese bikes: A Fuji from 1977 and a Panasonic from the early 80's. While the Fuji came with cottered cranks, both shells seem to be threaded the same, as I can interchange the cups: Fixed cup is left threaded; adjustable is normal. The Fuji is 68mm wide; the Panasonic is 70mm. The diameter, best I can measure (no calipers) is 34mm. I can't make these measurements fit Sheldon's table (http://sheldonbrown.com/gloss_bo-z.html#bottom) (which has no "Japanese" entry). Closest fit would seem to be Swiss?!? Anyone have good knowledge on what these might be? Or do I need to bring it in to a shop to have a "pro" tell me? Trying to figure out what my replacement options are, if any...
08-19-11, 05:43 PM
1.37/1.375" x 24 tpi
(34.8/34.9 x 1.06 mm)
08-19-11, 07:41 PM
Thanks. You sound pretty certain -- yes? And is this the "default" or easy to find variety? Is the 2 mm width difference a problem, or is that easily handled by the adjustable cup?
08-19-11, 07:49 PM
British/ISO is almost universal these days and I don't think the Japanese have ever used anything else.
08-20-11, 08:10 AM
If the cups are interchangeable, they're both English thread. Swiss thread would be highly unlikely on a Japanese bike in any case. The shell width does not matter provided you use an appropriate spindle for the bike.
08-20-11, 08:53 AM
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