Originally Posted by
miamijim
Not true. There are right side up and right side down headset bearings each corrsponding to whether or not the upper frame piece is a cup or cone style. They dont interchange and there are different diameters as well. Some headsets only came with 1 retainer.
There are few absolutes when dealing with vintage bicycles. Some amount of trial and error and common sense is required. I used the cages from a late 80s generic (JIS) headset on a Stronglight P3 headset recently. No issue.