I recently ordered a Shimano 105 5603 triple crankset and the corresponding BB. When I went to install it (brand new frame), the bearing cups screwed in beautifully and the crank axle slid through the drive side bearing cup, was lined up perfectly with the non-driveside cup and slid right through--about 1/2 inch-- and then stopped dead.

Pounding with the heel of my hand didn't do the trick--I ended up pounding it through with the rubberized handle of a claw hammer while holding a thick sheaf of newspaper in my left hand to keep from denting/scratching.

This is the third brand new frame I've built with these components (same models, not same items) this year and I haven't had this problem before.

I understand that if the axle was not lined up properly with the non-driveside bearing cup, it would mean the BB threading is out-of-whack and I would have to take it to be reworked. But in this case there is no alignment problem, just sticking there at the end.

I'm a little concerned since my understanding is that these external bearing cups do not hold up well against sideways stress. What could the problem be? All I can think of is manufacturing variances which compounded--ie the bearing of the smallest acceptable size limit paired with an axle of the widest acceptable size limit.

Most of all, I'm wondering what effect this is going to have on the life of the bearings . . .?.


Sorry I can't correct spelling error in title