Looks like you still didn't get an answer on this so...
As you probably know, Italian and English freewheels have the same thread diameter (1 3/8") and pitch (24 tpi) and differ only in the shape of the tread profile (55 deg vs 60 deg, and probably some other subtle differences). There is an analogous situation with the steerer tube dimesions. The result is that Ital and Engl. freewheels and headsets are essentially interchangable.... umm, no don't try threading a headset race onto your hub... I meant to say that Ital. headsets interchange with English headsets and Ital. FWs interchange with English FWs. Anyway, there is some concern with the quality of the fit when you mix specs, and switching back-and-forth is hard on the parts. Okay that's the background.
ISO stands for International Standards Organization. They designated a new thread spec that, as I understand it, provides better interchangeability with English and Italian parts. Whatever it did, it meant that manufacturers could make one type of part instead of two. Around 1991 I bought a Campy headset that was Italian threaded. In 1992 I bought another and it was a newer model only available in ISO. Around that time the Campy road hubs started coming through marked as ISO. I can recall reading in Bicycling magazine about forthcoming ISO standards at a time well before I could understand what any of it meant. That would have been in the very early 80's. That it took Campy until 1992 to adopt the standard... well that's the kind of thing I love about Campy.
Tom Dalton Bethlehem, PA
---------------------------------
Yahoo! Sports
Rekindle the Rivalries. Sign up for Fantasy Football