Originally Posted by
brian197
I was cleaning my bike and noticed a 4mm gap between the shell and the flange. Is this normal or should I take it to the shop?
No, it should not look like that. The next question should be does the crank move up and down and side to side (it should be wiggling all over the place). If so, somehow the BB fixed cup got unfixed and unscrewed. This is more probable with an Italian BB because the threads are not reversed (and tend to place pressure on the cup to unscrew) but I guess under the righ circumstances it could happen to any BB. I'm guessing you don't have the knowledge or tool to remove the crank arms, the BB should be removed and checked out. If there is no major scoring or pitting than it can be clean re-greased and re-installed. If you don't want to mess with it, just have your local bike shop replace the old BB with a new $25 sealed unit; should cost you about $30-40..