The lower head tube location part of the fixture changed many times. The big change was to pucks. Which is a very short cone, if you will, but one for each size of headtube. I'm a bit surprised nobody is selling pucks, there have to be people out there that need them. The cones weren't big enough, and a long cone makes it harder than it has to be to get the frame off of the fixture. I'm in the process of replacing the lower cone on my fixture with a series of pucks.