Imperial mark II bottom bracket

Submitted by howson1984 on Mon, 03/03/2014 - 20:51

hello fellow cyclists,

i was wondering if anyone has swapped or upgraded a stock BB to a newer style BB in an older style CCM.

i was given a an old imperial mark II, from the serial number im assuming it is a 1963... (if anyone can shed more insight on determining the age that would be great).... and the BB is a little rough. i plan to upgrade and i would take measurements and determine the BB shell width but its in my shed which is buried in snow. my plan is to order the parts now so i can have it all swapped before biking season is here. from what ive read the BB is a threaded english style BB, but if im wrong im hoping sumone can let me know.

can sumone can fill me in on an appropriate shell width and spindle length to have a proper chainline. your shared knowledge and experience will be greatly appreciated

happy riding

1 Comments

Submitted by rusty wheels on Tue, 03/04/2014 - 01:24.

The bottom bracket in your Imperial should be a one piece unit.  The cups are pressed into the frame and adjustment is done with a large wrench and screwdriver.  I have seen modern sealed units that claim to be a drop in for this style but have never personally tried one.  This route will require new arms and chainring, and you will lose one of the very distinct (and stylish) parts of your bicycle.  New cups and bearings, adjusted and lubricated correctly will give you many miles and years of smooth service for your existing crank.  If you are really determined to convert it I may be able to get some measurements for you from my 65'.

Erik