Originally Posted by
eschlwc
i wonder why the track and road versions of campy headsets use different sized bearings.
Larger balls can take more abuse and thus were considered more appropriate for the road, where surface conditions may be rough at times. The track is more likely to have a smooth surface and less need for the larger balls.
FWIW, the Campy "Sport" headset also used the smaller balls, and in fact appears to be identical to the Pista headset except for the threaded cup, which has only two wrench flats vs the octagonal flats on the Pista. Sport headsets are often confused for Pista headsets, but it really only matters to hipsters anyway.