I am assembling a bike with first generation Dura ace. The headset race is cracked thru and I am searching for a replacement among the other spare headsets I have. None of them are the first version Shimano that I am trying to piece togeather. What I am identifying as first generaton is the one which has a grove around the fat part of the head cup but no identification other than Dura ace on the locknut. The total thickness is whats throwing me off . I keep measuring the cracked one at 9.6mm or so but every other crown race measures short of what Sutherlands says they should be. Campy NR is supposed to measure 9.9mm but only measures 8mm (and I have measured 3 or 4) so whats up with this? My problem is the cup is so deep it will litterally drag on the fork crown with a shallower race installed.
Any ideas? And no I dont think its a
measuring error on my part as I work to the closest MM everyday with the
very same caliper.
BOB FREITAS
scratching his head in MILL VALLEY,CA USA