I need your help.
I understand that there are usually 2 diameters for headset fork crown races- 26.4mm, which is Campy style, and 27.0mm. On the Stronglight V4 competition headsets that I have, there are actually 2 inside diameters, the 27.0 is oriented closest to the crown, and then there's a "shelf" that's 26.4. I'd like to think that the friendly folks at Stronglight designed this crown race to work with either size fork. If the fork crown is 27.0 mm, then the race will have a suitable pressed-fit, right away and won't go farther down because the 26.4 "shelf" will not let it. If the fork crown is 26.4, then the race will slide over and past the part of itself that is 27.0mm and then touch, or maybe slide onto a little, and get centered on the 26.4 part of its diameter.
Does this make any sense? I don't have a fork handy to test my theory, but I bet there's someone out there in CR land who knows whether this is what Stronglight did.
Thanks
John Barron
Minneapolis