What does the little clip on the Campy UT cup do?
On the drive side of a Campy UT BB cup, there's a little spring clip that fits into a couple of holes spaced about 180 degrees from each other.
The description in the Campy manual states that it is a "bearing retention clip" but it doesn't seem like it fits in deep enough to hold onto the bearing that is press-fit onto the crank spindle.
Keeps the crank arm from coming out.
^^^ that would be pretty scary. I assumed it was some sort of backup or safety for the case when the UT bolt came undone, but it seems pretty puny for that task. Plus, what about the non-drive side.
The clip holds the DS bearing in the cup. the NDS is held in by tension. Dont take that clip out because otherwise your crank won't work
I just found a cutaway drawing online that shows how it interfaces with the bearing and I now understand how it sits. I am surprised how shallow the pin ends are, but I see that they do go down far enough to hold the bearing.