Originally Posted by
Poguemahone
Partially correct. Many older Japanese bikes used the now obsolete JIS headset sizing, which utilized a smaller headset cup diameter (30.0) and a larger fork crown race diameter (27.0). Can be over came by a competent shop with reaming tools.
Geez.....I can't believe I missed that! I've had no less than 3 bikes get a headset swap in the last year that required a trip to the LBS for some reaming and cutting....