Originally Posted by
Bianchigirll
Is there a difference in diameter of the headset and steerer tubing? Why not just put a new and long English threaded steerer or threadless steerer on the fork?
+1
Or just use a nice old ISO fork and headset and be done with it. The cup size of French and ISO are both 30.2mm. Even a JIS fork could have the crown race reamed to ISO and used as well.
Having the steerer unbrazed and replaced with a ISO 1" might work but I'm not sure if the fork crown is different for and ISO steer tube than a French. Maybe they are the same, maybe they are different. But even if they are the same this is getting to be expensive after the brazing and repainting. Might as well just have a framebuilder make you a custom fork at that point. Easiest to just find a nice used ISO fork and convert to ISO headset if he doesn't want to mill the head tube down. But either are OK as far as I'm concerned. It's not like this is some super-rare museum-quality bike he's rebuilding.