I am converting an old MTB into a single speed roadbike. I am starting with a 1993 Giant Iguana frame, which I have stripped down, repainted and am now building back up. I have a 1-1/8" OD steerer tube on my threaded fork (1" ID) and would like to use a gooseneck 1" road style quill stem. (Possible a Nitto or Cinelli.) I have seen shims and adapters for using 1-1/8" stems with 1" steerers but nothing for the reverse.
So, is there any way to use a 1" quill stem on a MTB frame with a 1-1/8" threaded headtube/steerer?