Hope someone can help me with my headset problem. I have a 1" headset, threaded. After every ride, 15 miles or so, the headset becomes loose. Not by much, but enough to make that "clunk" sound. It seems to be coming from the lower bearing area. I have read the Park tool website for headset adjustments, and have adjusted the headset many, many times, but it loosens up again. It seems that it is either to tight, or loose, with not much adjustment room in between, less than 1/16th of a turn. The LBS did my headset last year and it works well for a while. I have also noticed that each time I loosen the lock nut, the washer with the tab in it has moved out of alignment. What could be going on here? I measured to see if the lock nut was hitting the top of the threaded part of the fork when tighten, but there is still some space when tightened. I am out of ideas.