"Chattering" noise from headset area over bumps?

[Oaky]

Headsets being a complete mystery to me, I am calling for help identifying the source of a noise from those who understand this black art...

I occasionally hear a noise, difficult to describe, but the best way I can think of is as a kind of chattering noise when riding over bumpy tarmac.

It seems to come from the headset area, and appears to be most prevalent when riding one handed (e.g. whilst signalling, drinking etc).

Does this indicate something wrong in the headset adjustment or is it normal?  (e.g. too much preload?, not enough preload?, bearings too dry? etc. etc.?)

I've noticed it on two different bikes, both have threadless headsets, with one having races internal to the head tube ewith cane creek branding on the conical spacer) and the other having external races above/below the head tube - FSA TH-857.  One is the bike I've had longest, (about 5 years old) the other is brand new.

Neither headset appears to have any appreciable play in it when rocking the bike backwards/forwards with the front brake on.  I did try that with my finger against the headset bearing junctions but felt no movement, as well as visually.

[Biggsy]

Not enough preload.

It can be tricky to eliminate the problem without having sticky steering if there is something wrong with the headset or head tube, but have a go.  Make very small adjustments at a time.

I suffered it badly on one bike even after I refaced the head tube (probably badly).  It's ok now I replaced the headset with a Campag Record.  It's more tolerant of imperfections than any of the several headsets of various types I tried previously.

Neither headset appears to have any appreciable play in it when rocking the bike backwards/forwards with the front brake on.

They possibly could reveal play in that test if you do it violently (which I'm not necessarily suggesting).  There should be no play at all, ideally.  Another test is to drop the front of the bike from a few inches on to a hard surface - to attempt to make the same noise as currently happens when you ride over a bump.

[Tail End Charlie]

I'd go for not enough preload aswell.
Have you tried seeing if there's movement after turning the front wheel 90 degrees, applying the brake and rocking? This eliminates any play in the brakes.

[Oaky]

Thanks - I will try again, with TEC's 90 degree trick, and up the preload a bit anyway.

It's probable that the older bike is my fault as I have moved spacers on that one, so could have got the preload wrong whe reassembling.  the other bike is new, and due for it's first (free) service, so theoretically, I could ask the shop mechanic to sort it out, on the other hand, adding a bit of preload is something that I know how to do, so I'll give that a go first.

There's no comparable noise on either bike when dropping the front end.

[mrcharly-YHT]

Headsets being a complete mystery to me, I am calling for help identifying the source of a noise from those who understand this black art...

I occasionally hear a noise, difficult to describe, but the best way I can think of is as a kind of chattering noise when riding over bumpy tarmac.

It seems to come from the headset area, and appears to be most prevalent when riding one handed (e.g. whilst signalling, drinking etc).
....

I've noticed it on two different bikes, both have threadless headsets, ......

Two possibilities come to mind:

You have one of those watches with a clattery metal strap

Your false teeth are loose

IGMC

[MartinC]

Your false teeth are loose

Ah, so that's what a headset is!

[PH]

Do the bikes have mudguards?  I used to get a similar sound from a front one, I thought it was the headset.  Probably not the case but it's an easy one to eliminate by just taking it off for a while.