Bike Forums - View Single Post - English vs French BB question?

01-08-14 | 11:17 PM

#17

dddd

Ride, Wrench, Swap, Race

Joined: Jan 2010

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From: Northern California

Bikes: Cheltenham-Pedersen racer, Boulder F/S Paris-Roubaix, Varsity racer, '52 Christophe, '62 Continental, '92 Merckx, '75 Limongi, '76 Presto, '72 Gitane SC, '71 Schwinn SS, etc.

Quote:

Originally Posted by purebikes

Thanks for the help guys. I got this from the sheldon brown site, which seems to be what is happening.

When trying to interchange a english BB in a swiss bottom bracket = "35 mm = 1.378". Shell is slightly larger, thread pitch slightly finer. May seem to fit, but will be loose."

http://sheldonbrown.com/cribsheet-bottombrackets.html

I tried a phil bottom bracket cup and it fit a little better but still loose, so I guess I will try a swiss BB and see.

Since the Swiss and English diameters are so close, it's the thread pitch difference that causes any differences to manifest as a "tight" fit.

I'm betting that a Swiss BB will not only be "tight", but that you will have to muscle it in.
Hopefully the wrench flat configuration will be favorable to heaving on a big wrench.;-)
Just curious, did you try to torque the English fixed cup home? Wondering if it felt solid as the flange bottomed against the bb shell.

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