Would a 73mm Bottom Bracket Work in a 70mm Shell?
01-29-08, 01:47 AM
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Would a 73mm Bottom Bracket Work in a 70mm Shell?
Anybody know if a Philwood 73mm bottom bracket would work in a 70mm shell? I'm thinking it would just mean a few extra threads of the retaining rings stick out.
01-29-08, 01:57 AM
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no. a 70mm shell is going to be italian threaded, and also a different diameter, if it is, in fact a 70mm shell. 68mm, or 73mm have the same shell diameter, differing in width, and about .005" in thread pitch. a 70mm bb will have a 70mm shell width, but with a larger shell diameter, different thread pitch, and the right side cup is right-hand threaded, rather than left. the appropriate measurements can be found on this page.
01-29-08, 01:58 AM
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Isn't a 70mm shell an Italian thread?
Either way, I would attempt it during the winter season just to see what happens, but it probably won't work.
Either way, I would attempt it during the winter season just to see what happens, but it probably won't work.
01-29-08, 02:01 AM
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BTW, OneTinSloth taught me most everything I know. I'd follow his lead. I call him Sheldon "Listen to OneTinSLoth" Brown.
01-29-08, 11:49 AM
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no. a 70mm shell is going to be italian threaded, and also a different diameter, if it is, in fact a 70mm shell. 68mm, or 73mm have the same shell diameter, differing in width, and about .005" in thread pitch. a 70mm bb will have a 70mm shell width, but with a larger shell diameter, different thread pitch, and the right side cup is right-hand threaded, rather than left. the appropriate measurements can be found on this page.
01-29-08, 01:06 PM
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OK, I get that the 70mm shell has a different diameter than the 73mm and why a 73mm BB generally won't fit into 70mm shell. However, wouldn't a Philwood specific 73mm BB still work in a 70mm (Italian) shell when using a Phil's Italian retaining rings? From what I can tell, all Philwood bottom brackets have the same diameter. What they then do is sell various rings to fit the various bottom bracket types.
