Originally Posted by
JohnDThompson
You know what they say about "standards:" the best thing about them is that you have so many to choose from!
Right.
Quill stem diameters that I've seen: 26.4 mm (old Cinelli), 26.0 mm, 25.8 mm (old 3TTT), 25.4 mm, 25.0 mm (old French) 22.0 mm and 24.0 on old Raleighs with steel bars, e.g. Sports.