Post 2, FB, says the solution for grit getting into a headset (if this is what's really going on, still not really known yet). A seal made of a section of inner tube. I've done this to a number of bikes over the years and it is the best way to limit infiltration.


Now as to grease going bad- sorry but I don't buy this theory. Grease is going bad from before it's placed in a bearing, before the bearing is serviced, before the bike is 20 years old and with no use in the last 18 years still runs well. Grease gone bad shows as hard but smooth bearing action. Or sticky action like in brifters many years old. Not as getting gritty with no additional grit added.


I strongly suspect either poor initial installation, adjustments or contamination from the outside. But the solution's start is easy. Take the headsets apart and tell us what is found after really understanding. Andy.