bikeworkshop
Old School Grand Master
For anyone unfamiliar with the madness of cycle standard names:
The "inch" name refers to the fork standard. It's the outer diameter of the fork steerer tube.
An "inch quill" stem has outer diameter 22.2, because it fits inside the inch threaded fork.
For postwar (British) standard quality cycles, the (1" outside diameter) tube used for the steerer had a wall thickness of 1/16", so the inner diameter is 7/8", which is 22.2mm (to 3 decimal places).
It's called "an inch quill", but it measures 7/8", or 22.2mm.
The "inch" name refers to the fork standard. It's the outer diameter of the fork steerer tube.
An "inch quill" stem has outer diameter 22.2, because it fits inside the inch threaded fork.
For postwar (British) standard quality cycles, the (1" outside diameter) tube used for the steerer had a wall thickness of 1/16", so the inner diameter is 7/8", which is 22.2mm (to 3 decimal places).
It's called "an inch quill", but it measures 7/8", or 22.2mm.