Originally Posted by well biked
If you can press them in by hand, they must be JIS cups. They might work, though, since you say they're "snug" -
Yeah, that's the assumption - I have a JIS headset (older Japanese) and a frame that needs an ISO headset.
I must be getting confused, as I thought the cups were the same and the crown race was only different in the ID.
I'm thinking that the best bet might be to buy a new ISO headset. They're not too expensive and I'd hate to ruin the frame over something so trivial. The only part of the old headset that I really want to use is the top race cap that encloses the top bearings, and it should fit ok over an ISO cup.