27.0mm is the Japanese Industrial Standard (JIS) for crown races. Most high-quality crown races are the "Campy" standard of 26.4mm. It sounds like you have a JIS fork and a "Campy" spec. race, although your measurements don't bear this out precisely. Nevertheless, it can be hard to measure these parts precisely and they are nominal dimensions anyway. The fork is actually a touch larger than the race because it is a press fit, but the .2mm diff you've got isn't workable. I'd take the fork to a good shop and have it milled to the more common (on good bikes, anyway) standard of 26.4mm. Hopefully your race will fit at that point. If not, any common high quality HS should. BTW Tange Levin races are markes either 26.4 or 27.0. Other models may be unmarked, but check yours. Tom Dalton Bethlehem, PA Warren & Elizabeth <email@example.com> wrote: I'm swapping out the Tange headset on my Centurion track bike and I'm finding that the steerer is a little larger than my races. The steerer measures 26.8 at the base while two different NOS steel headsets measure in at 26.6. That may not seem like a big diff, but it is sizeable when trying to push those hardened steel races down flush to the fork crown.
Are there subtle"oversized" headsets or does this require a different form of persuasion. Should I just button up the headset and it will press together fine?