Issue with a frame.
When the forks are fitted and you turn them, the motion is not smooth and is staggered /jumpy as if there is an obstruction in the head tube or an issue with the H/S or H/S bearings.
Taking apart the H/S to investigate, I find that the crown race and bottom Cup have indents pretty much all the way around from the H/S bearings -
Head tube is clear with no obstruction
Steerer tube appears in order
H/S appears to be in order
Top cup is fine
Cleaned everything and regreased and put it back together and the movement of the forks is still staggered and bumpy.
The frame and forks don't show any obvious crash damage.
Any ideas on how to improve the issue, Does the H/S need replacing, New bearings, Different sized bearings,Loose bearings rather than a cage, Different grease (I use common grease and never had any problems)
Needs new crown race, lower cup and Lower bearing.
Ta very much.
It’s called brinelling. No grease, and small repetitive movements mean the bearings wear tiny pits into the races. Just easier to replace the whole lot, tbh.
Or Google fretting for the scientific explanation :)
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