Originally Posted by
unworthy1
wellbiked has it right, you just need to retain the top nut and the top THREADED cup since those are the pieces that fit the "undersized" steerer. You will also need the crownrace that fits your fork's crown, or have that milled to 26.4 if it's not already.
Actually it's just the lock nut at the very top that's sized to fit the .833" stem, the threaded part of the lock nut and also the threaded race is the same as a standard ISO 1" headset. In other words, the outside diameter of the steerer tube is standard 1" stuff, including the threads, it's just the inside diameter of the tube that's smaller, and therefore the stem's quill has to be. The idea was to have a thicker-walled steerer tube, but at the expense of a smaller diameter quill-
