Originally Posted by
cyccommute
Whatever you want to call it, it went away with the advent of threadless headsets which don’t loosen. If “fretting” is the mechanism, why doesn’t it happen in a headset that is properly loaded? Threadless solved the problem.
"Modern" threadless design solved the fretting wear problem by adding an additional bearing surface between the frame and the ball bearings.
Old headset was
frame-race-ball-race-fork.
Modern headset is
frame-race-cartridge-race-fork. The
race-cartridge-race combination acts as a plain bearing that accommodates the fork vibration, so the cartridge-ball interface doesn’t vibrate to produce fretting wear.
Typical Threadless Headset