hey guys --

i was looking for old posts about profile bearings & ran across something i've never heard before & was curious about. need an explanation, please.

someone posted about needing a gap somewhere when installing the bearings & i couldn't really tell where they were talking about.

guess #1
did they mean that you're supposed to have the aluminum bearaing carrier not pressed into the bb shell all the way on the drive side, so that there'd be a gap between the lip of the carrier & the outer face of the bb?

guess#2
did they mean that you do have the aluminum cups both pressed in tight to the bb, but on one side, the bearing isn't pressed all the way into the carrier
when both bearings are touching the center spacer (so that one bearing itself is not bottomed out in the carrier & the spindle bolts aren't cranking down on the bearings too much & creating a lateral load, because they're already stacked out by the spacer)

guess #3
are you supposed to have a center spacer that's slightly too short for the space between the bearings so that you do end up with a lateral preload on the bearings?

i've never heard of this stuff before,and have never had an issue with it before -- i just measure the width of the bb shell, slap in the appropriate spacer & go with it. i've even had to make a spacer once or twice out of conduit, and even those worked fine. but maybe i'm just a lunkhead about cranks & too easily satisfied.

just curious about the finer points of profiles.

thanks!

Guess #1 is closest to being correct. The drive-side bearing should bottom out on the center spacer slightly before the aluminum cup is pressed all the way into the bottom bracket hanger of the frame. That way when you torque on the spindle bolt you can't put any sideload on the bearings. The "gap" that were talking about is very small though. Like a couple of millimeters.

#1, but the 1/16" - 3/32" gap should be on the non-drive side. See page three of these instructions (Illustration #3) - http://www.profileracing.com/manuals/3piececrankset.pdf

Oops, he's right, non-drive side. You put the drive-side bearings in first! Sorry 'bout dat!

Yeah chunkster , I had to buy a piece of condiut as well for some reason both spacers I tried still had quite a bit of play after the bearings were pressed in like the Profile's instructions read. After everythimg tightened down the cranks do spin alot more freely than before.