Hi folks,
Here's one to chew over. Yesterday David Bilenkey and I were dismantling the Tange Seiki headset on the 82 Bob Jackson to replace it with a Campy SR headset. Once we had unscrewed the lock ring and removed the adjustable race the lower head race just dropped out of the head-tube with no persuasion necessary. The upper head race then also just slipped out with no effort. As we set about putting the SR crown race on the steerer we found that it didn't fit - common occurrence maybe - the steerer was cut for a JIS 27mm inside diameter race and of course the Campy race did not fit. I know that it is no problem getting the steerer cut-down (which is now being done).
What was curious though was that while the steerer was cut for a JIS (or maybe Italian fitting according to Sheldon's Glossary) and the head races both were 30mm inside diameter, the head-tube itself has a 30.2mm inside diameter - standard ISO! Has anyone else encountered this mixing of standards before?
Paul "bicycles continue to amaze me" Williams, Ottawa, Ontario, Canada