Bicycle Mechanics - BB spindle directionality

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FlatMaster
02-13-09, 01:53 PM
I recently rebuilt my BB. With hindsight, I find that the drive and non-drive sides are not necessarily the same. biketutor.com says the drive side square taper is longer to accomidate the chainrings. However, I noticed no difference between the two ends of the spindle when taking it appart. After rebuilding it, the chainrings appear to be in the same position as they were previously and the front derailure is in the optimal position for the high and low limit screws. Was I lucky in putting the spindle back in the correct way or are spindles now bi-directional? The bike is a specilized Cirrus from the 80's

DOS
02-13-09, 01:56 PM
Some spindles are symetrical, some not. You may have a symetrical one. Or its slightly assymterical and you got lucky -- you had 50-50 shot to get it right.
frankenmike
02-13-09, 01:59 PM
I actually flipped one on purpose once to get a better chainline for a ss conversion.

Bill Kapaun
02-13-09, 03:14 PM
I have 2 bikes that use the same spindle.
The double uses the short end and the triple uses the long end.
I think the factory just wanted to reduce parts inventory back in the 80's?
FlatMaster
02-13-09, 04:52 PM
One more thing. I noticed there was some pitting, but I reinstalled the spindle temoprarily. One side had much more damage than the other. Can I assume this was the drive side?
dsellinger
02-13-09, 05:01 PM
One more thing. I noticed there was some pitting, but I reinstalled the spindle temoprarily. One side had much more damage than the other. Can I assume this was the drive side?

It may also have been the side with not enough grease, or the side that got wet, or the side with a bad bearing.
I_bRAD
02-13-09, 05:10 PM
If the chainline is correct, it doesn't matter which way it goes in
FlatMaster
02-13-09, 05:16 PM
Looks like I'm in the clear for now. THanks
Bill Kapaun
02-13-09, 07:08 PM
Did you notice the "code" on the spindle. If it's for a 68MM shell, it'll be something like 3-x, where x is a letter. 3-S is still available from Loose Screws, along with cups.

http://www.loosescrews.com/index.cgi?d=single&c=Bottom%20Bracket&sc=Spindles&tc=&item_id=SU-3S&id=54713009168