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So .... Let's talk about damaged headsets(3 posts)

So .... Let's talk about damaged headsetsAllUpHill
Jul 10, 2003 8:16 PM
The issue at hand is pitted headsets, or so I believe. When I hang the bike up (horizontally, by the frame) or hold it off the ground the fork "notches" into the straight-on position. Not really indexed at regular intervals all the way around, just a single self-centering "notch."

My question is, what type of mal-adjustment allows this to happen ... over-tightening or under-tightening? Or something else such as too little lube? I understand that the "other" type of pitting (with notched positions all the way 'round) comes from OVER-tightening. And that makes sense, since you're pressing each bearing to the point they form regular dents in the races. One of my housemates claims that the self-centering pit results from the sum of all the tiny impacts as one rides along, and it forms in the center position because, on average, your steering position is straight-on. Based on that explaination, it would seem to be a result of under-tightening the headset.

Also, does this pitting occur on the lower bearing set, the upper bearing set, or both? I'd guess the lower, since it bears your weight and takes the impacts. I need to get this sorted out before I go installing replacements, since I'm consistently letting it happen ... on two bikes, one with a threaded HS and one threadless.

Thanks in advance.
re: So .... Let's talk about damaged headsetsAkirasho
Jul 10, 2003 9:39 PM

Be the bike.
I think the article nailed it. ThanksAllUpHill
Jul 11, 2003 8:39 PM
Took the threadless one apart today -- the bike I ride the most in the rain. The lower bearing was on the dry side--should have broken it down to re-grease weeks ago. Slight dimples were the most evident on the front and rear of the cups and races. I also think I had it slightly over-tightened, but according to the article, lack of enough grease was the main problem.