I was installing a Shimano M-580 mountain crankset with integrated bottom bracket on my touring bike last night.
The "right adaptor" gets screwed into the BB shell and then the "left adaptor" gets screwed in. Then, you put the crank unit through the middle so that it comes out on the left side and then attach the left crank arm. You are supposed to add spacers in between the adaptors and the lip of the BB shell. I didn't do this and when I tightened it up, the black plastic piece bewteen the two adaptors buckled and broke.
Needless to say, I got mad (at myself, of course). I took it back apart and removed the plastic piece altogether (wasn't too hard since it was broke), then put the crankset back on minus one black plastic sleeve. It seems to ride fine without it. All it really does is act as a sleeve (right??) I looked around the net and couldn't find anywhere to purchase just the piece I broke. I ended up purchasing a whole new crankset, but if I hear that it will be fine the way it is, then i can always return it the new one when I get it. Any thoughts? Should it be okay the way it is, or do I chalk this up as an expensive lesson learned?
-a generic sleeve for a cup and cone bottom bracket is only a buck or two
-I would do something about it. I would start with duct tape. The sleeve is light, so the pieces couldn't have gone too far when you tried to hurl them across the shop. Doing nothing could allow your new bottom bracket to become contaminated, and may ruin a bike tour.