Re: NOS-NIB Shimano Deore DX, XT & XTR stuff
1" ISO is 30.2 OD on cups, 26.4 ID on crown race
1" JIS is 30.0 OD on cups, 27.0 ID on crown race
I only know this as I recently spent an evening tryin to fit an ISO headset onto a JIS frame and forks. I know shimano made both at the time (ISO is more common though) but I don't know how they differentiated between them. The 'English' on the box might be the giveaway as I'm not sure what this refers to.
Best way to tell is the measure with some verniers. If either happens to be JIS I'll be interested.
Cheers
Paul