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It really depends what you can put up with. If you’re used to this so called Chris King level of headset smoothness then you’ll notice just a little bit of notchiness. Personally, I don’t mind a slightly rough headset, but I don’t like a tight feeling headset which won’t centre nicely; and I also don’t like a headset which has worn itself badly in the middle position. That’s your headset indexing. At that point, it can feel like it’s springing itself into the straight ahead position and it can make the bike feel alarmingly unstable at low speed.
There’s a quick bodge/dodge/fix though. The divots are worst in the straight ahead position and directly above one another where the balls sit. If you pop the cups out and turn them round a bit, you’ll move the divots out of the straight ahead position and it’ll stop trying to spring into the centre position. They also then don’t line up and some of the notchiness is reduced.
I keep meaning to come up with some kind of a tool for lightly re-facing headset races. I’m sure it would work like lapping in valves on an engine, with a couple of grades of grinding paste.
Jonny69-
That’s great, thank you. Good tip turning the cups.
I can’t remember exactly what the machine shop needs but pretty sure it’s an annular something or other. Not a huge surprise! Didn’t seem like many places have one when I was looking.
As far as I know lightly refacing would be fine, I think the metal under the bearing surface is softer though isn’t it? That was the question with mine - could it just be re-faced or would it need hard chroming as well. Starts to get a bit pricey!
Please put my name down for one of your tools!
veloham
@clubman re indexed headsets ... I've been meaning to ask, how bad does it have to be before it's noticeably notchy? Totally agree that ~ 50% of headsets I get my hands on are at least slightly indexed in the lower races. I should try one and see how it feels, never really fancy fitting and removing a headset (in a nice frame) for laughs though.
I have had a couple of crown races ground at a machine shop and they did a great job. Took ages though, almost like a £30 job was a bit of a faff :)
Edit - should have said clubman or anyone else :)