Dia Compe Headset woes

mk one":7oy1sl7o said:

I always coat the bearing races in grease too, rolling the bearing around so they are completely covered.

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Yeah, made sure I used plenty. All the other bases are covered too which is why I suspect wear. Its quieten down enough now for it not to be a huge issue with the additional bearings in but may get the LBS to give it a once over for their opinion on what's what.

RobMC":1kt2fjxf said:

TheAntsPants":1kt2fjxf said:

Bearings come in different grades (out of roundness). It's unlikely to cause "grinding", but could you have bought very low grade bearings or low grade race? The cheaper they are, the harder it is to tension it to prevent grinding. Also, I assume you haven't over tightened the top cap?

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I havent over tightened it, thats the first thing I checked, however you might be right about the bearings. I just bought the cheapest packs from SJS so there is every chance they arent of the highest quality. Or the headset is worn out, of course.

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If it's their standard bearing then it'll be Grade 100, which are perfectly fine for this, if it's the weldtite one, I have no idea, I think they are grade 1000.

Other than that Grade 25 or higher are a bit pointless for this task, Grade 25 is XTR level and the races will be nothing like the bearings.

Crown race pitted, over tight, and/or the lower plastic seal the wrong way.

Woz":3vxpz05w said:

Crown race pitted, over tight, and/or the lower plastic seal the wrong way.

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Ruling out being over tight as Im 99% sure its not - which way round should the lower plastic seal go? Im fairly sure when I removed it the flat face faced the Crown Race and the 'stepped' side faced the bearings, which is how Ive reassembled it. Thats what it looks like here, although mine is Threadless -



As Ive said, wont be surprised if its wear related but happy to rule out other possibilities.

dyna-ti":acm07hwo said:

99% of ball bearings a cyclist is likely to buy are accurately ground. I dont believe for a second its that precise.

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Believe me, better grade bearings make for smoother running and a longer life. The price difference is minimal, especially from a bearing supplier as opposed to the lbs.

FluffyChicken":3boweeif said:

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Interestingly, the 5/32" bearing cages I had didnt sit in the cup like they do in image 6, they were closer to the fork steerer tube but thats sort of irreleavnt now Ive put the individual bearings in as they sit within the cup as pictured.

Have you overfilled / wedged the headset with balls? I was always told to fill em right up then remove one to avoid binding. Some headsets seem worse for this than others. Ritchey seem very susceptible.

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Going back to basics , you mention that this bike is a recent purchase . Is this headset original to the bike ? has it been replaced and fitted incorrectly so that
the top and bottom tracks are no longer parallel in the head tube ( typically after a paint job ) does the bottom track sit correctly at the base of the fork steerer tube ?
and in the worst case do the top and bottom faces of the head tube need to be checked for parallel ? and re-faced ( LBS )

If any of the above faults are present there will always be tight spots as you steer

All this being ok there should be no problems ! however you did not mention how you decided on the correct loose ball bearing diameter ?

As a final comment , the grade of ball bearing to be used in this application is really unimportant , there are millions of cyclists out in the world
who have more important things on their mind ( like not being knocked off their bikes ) than concern themselves about the exact hardness and degree of
out of round of the ball bearings in their headset . If you think about it, the headset bearings have a pretty easy life anyway, making just a few rotations as the
fork moves left and right , unlike b/b bearings which really work quite hard in comparison

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Can't help thinking your lower seal is the wrong way round but I may be reading it wrong. I recently had problems with my headset knocking although it was an impact headset. The problem was I didn't install the lower seal because it's all chewed up after the previous owner installed the wrong bearings. I've been unable to find a new seal so tried to make do with what was left of the old one. In my case the seal is stepped, kind of like an L shape. The seal sits on the crown race and then over hangs downwards creating a seal with the bottom of the crown race and the bottom headset cup.