Originally Posted by
Trakhak
If the movement is only front to back and is confined to the bottom of the headset, that suggests that the head tube has become "ovalized," such that the bottom headset cup is no longer firmly held in place and is rocking forward and backward.
I had that happen on one bike, an early steel hybrid that I rode hard on rough single-track trails. A car mechanic I described the problem to recommended one of LocTite's tougher formulations. I used it - problem solved. Cheap fix. Might have been this one:
"LOCTITE 660 is a high-strength retaining compound with good gap-filling properties, ideal for repairing worn-out seats, keys, splines, bearings, or tapers without remachining."
Edit: as I recall, it takes some hours for the compound to harden. Might be best to keep the headset press in place for at least half a day or so.
Interesting. This could very well be the case. I have adjusted over and over again and it feels as if its properly adjusted and then it works loose just by me rocking the bike back and forth with the front brake activated. I have used Loctite on bottom brackets where theeads were damaged. Worked well. I will investigate further.