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Technical & Reference Section => Tech and Restoration => Topic started by: SaMAlex on July 15, 2011, 10:44 AM

Title: Drawing / Size for BB cups
Post by: SaMAlex on July 15, 2011, 10:44 AM

Im thinking of knocking up a few BB cups. I have some old ones that I could measure but they are all pretty beat up, and its always better to get the size they were meant to be, rather than reverse Engineer them. Does anyone have a drawing or spec of the size BB cups are meant to be?


(I already know this is a hard question cos I dont think there is an actual standard on the size of USA BB shells!)

Title: Re: Drawing / Size for BB cups
Post by: Dannywhac on July 15, 2011, 12:07 PM

Dunno if this'll help Alex - just rattled it up but it's reverse engineered from a Profile BB cup - US BB:

A: 11.44mm
B: 2.75mm
C: 53.66mm
D: 3.19mm
E: 6.89mm
F: 4.11mm
G: 51.13mm
H: 51.54mm
J: 14.19mm
K: 6.19mm
L: 32.37mm
M: 4.455mm

Means bearing cup diam: 41.28mm
Actual Bearing Diam: 41.35mm

(http://i1236.photobucket.com/albums/ff443/dannywhack/BTMBDimension.jpg)

Title: Re: Drawing / Size for BB cups
Post by: SaMAlex on July 15, 2011, 01:06 PM

Thats cool, thanks.  :daumenhoch:
I have ordered some new bearings. I might have a go at making some cups when they get here.