Originally Posted by
clubman
Usually by mistake. I had a 96 ELOS Cramerotti with such a shell. The story is the mechanic (kid) was talking on the phone, as he was facing the drive side of the bike and took too much off. They had to add a 2 mm spacer to get the BB and crank out far enough for the Chorus derailleur to be in range. I got a decent discount on it and it worked fine but it was annoying just to know what the clown had done.
I've got a '73 DeRosa with a 68mm wide Italian threaded bottom bracket. It came to me that way. It was a repaint, so my guess was that the 2mm were cut off to remove rust. Could have been anything though. A couple of spacers fixed the problem.