Cannondale BB Bearing - WTF?
 

Currently tearing down my latest acquisition, a banana 1987 Cannondale ST400. It can be seen hanging out in my garage in the picture in this thread...

http://www.bikeforums.net/showthread...443-80-s-Night!

Anyway... I disassemble the BB expecting to see the usual retainer full of bearing balls but instead I see this... some kind of metal ring holding them in place...


...and had a 'wtf?' moment.

Do I just pry out one of the balls and the rest will follow? There's a lot of grit hiding behind them and I'd rather clean thoroughly and optimally replace with grade 25's before reassembling.

~kn

Can't say I have ever run across one of those. I would say there are 3 ways to deal with it.

1- flush it as-is and re-grease

2- disassemble it and replace the bearings, re-assemble

3- disassemble and replace the bearings without putting the retainer back

Just be ready to replace it if disassembling it kills it because it's designed to not come apart.

kn, It'll take a more imaginative person than I to figure out how to disassemble that assembly non destructively! If it were mine I'd flush it with brake clean and regrease.

Brad

Yeah... it's probably the route I'll go. If I pry one out and somehow FUBAR something, I'd be off to sealed cartridge land. Maybe somebody will chime in with "I've done it a dozen times, no problem".

~kn

I had the same question when I cracked open my SR400

Here is the thread

gently pry out the retainer; clean everything; replace the balls; reshape the retainer if it became distorted whilst prying out and reuse it.

I don't like having parts left over........:thumb:

Cool. I see in the last picture on your thread you have the adjustable cup with just the black ring sitting on it. Did you end up replacing the black ring and that metal sleeve?

~kn

Your not supposed to have parts left over???? ;)

What about reflectors? ;)

~kn

I don't consider reflectors to be parts..........they are decorations.....

IIRC it went back in with the black seal and I ditched the bearing retainer /"sleeve".
(I always run my bikes with just loose ball bearings.)

Suntour sealed bearing BB- typical for this model and year. Bearing replacement (or entire BB replacement) is the way to go- bearings are pretty cheap (I think I paid $10 for a pair the last time I rebuilt one of these), the sleeve keeps the inside race of the bearing correctly oriented. These are "adjustable" for proper chainline- both drive and non-drive sides have lock rings and the entire BB can be moved a couple of mm to one side or the other to get the correct crank orientation.