Self-loosening threaded headset mystery...advice appreciated

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sarniacycle
Posts: 199
Joined: 17 Jun 2012, 1:19pm

Self-loosening threaded headset mystery...advice appreciated

Post by sarniacycle »

Hello and thanks in advance to anyone who can help solve this puzzle that's driving me mad...!

First off, here's the headset, a steel, no-name jobby:

headset.JPG


Now problem:

a) It loosens after a short (20 minute) ride.
b) Tightening the top race is a very fine balance between stiff steering and rocking/knocking/too much play fore and aft when I clamp down on the front brake.
c) Once I've got the top race to the right pressure I tighten the locknut down (2 spanners, 1 holding the top race in place, the other on the locknut). Tightening the locknut, whilst the race is held in place, also tightens the whole headset... (it shouldn't, right?) I can't figure why for the life of me and it's driving me mad. Though the answer to this is quite possibly the answer to the problem of it loosening...or connected.

Some other bits of info that might be useful...or not.
1) It seemed ok for the first 2 months or so after I first put the bike back together. What's changed? Nothing as far as I know, no falls, heavy knocks to speak of...
2) There's no caged bearing to be upside down, wrong way round or otherwise, they're loose balls. (I did replace these myself...I'm wondering if I got the wrong size, could that make a difference? Though I'm pretty sure the bike shop measured them for me there and then with a pair of calipers and all. Full set of balls -1 as per instructions elsewhere.)
3) The locknut's not bottoming out on the top of the steerer.
4) I thought the tightening of the locknut, if the race had stripped-ish threads and so a bit of play in it, might cause the race to push down too but having another look now, the race seems pretty good and moving it up and down, without turning, produces no noticeable vertical movement.

Any advice whatsoever will be sorely appreciated, it's driving me barmy this!

Thanks, Adam
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NATURAL ANKLING
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Re: Self-loosening threaded headset mystery...advice appreci

Post by NATURAL ANKLING »

Hi,
Assembled wrong :?:
Cups not seated yet :?:
Tightening lock nut WILL tighten race.....yes :!:
NA Thinks Just End 2 End Return + Bivvy - Some day Soon I hope
You'll Still Find Me At The Top Of A Hill
Please forgive the poor Grammar I blame it on my mobile and phat thinkers.
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531colin
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Re: Self-loosening threaded headset mystery...advice appreci

Post by 531colin »

That's a very long thread on that fork. ....top adjusting cup, lots of spacers, locknut. It shouldn't matter.....
I don't think the adjusting cup and top fixed cup look like a matching pair....the "overlap" just looks odd to me. If they are not a matched pair, the ball tracks could be a mis-match too, which might be your problem
There is always some "backlash" in a screwthread. when you tighten the locknut, it will always tighten the race.....on hubs, on pedals, on headsets, on Ashtabula BBs....You have to guess the adjustment, lock it off....re-adjust, lock it off....check again....
Wrong size balls wouldn't work at all, I think?
Valbrona
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Joined: 7 Feb 2011, 4:49pm

Re: Self-loosening threaded headset mystery...advice appreci

Post by Valbrona »

Someone who didn't know what they were doing fitted that fork. You have to really cut the excess off the threaded steerer tube. The excess should not be filled-out by spacers. Do it right and the top locknut should tighten against the top bearing race.
I should coco.
sarniacycle
Posts: 199
Joined: 17 Jun 2012, 1:19pm

Re: Self-loosening threaded headset mystery...advice appreci

Post by sarniacycle »

Thanks 531colin, Natural Ankling and Valbrona - I've just seen your comment now - thanks too.

- I've checked the cups and they're well seated
- Good to know about tightening locknuts! Thanks. It's been driving me mad.
- That just leaves the self-loosening. I think your point is true Colin, I hadn't noticed but looking now, the metals look burnished in different ways as if the top fixed cup and top adjusting aren't matching - if that's the case I suppose having the bearings in a cartridge might have at least held them in line and reduced any wiggle that, now loose, they're allowed to do and so loosen 'upstairs' too. That would explain why things started to auto-loosen round about that time I swapped them round I guess. Valbrona - I think there probably is too much space there but a few spacers are alright, surely? Though maybe any wiggle is amplified. Hmmm. Maybe if I coarsely sand the mating surfaces of the spacers it'd help them to keep their grip, one to the other.

Thanks folks. Still interested if anyone has a miracle cure...though think that's unlikely!
Cheers.
fatboy
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Re: Self-loosening threaded headset mystery...advice appreci

Post by fatboy »

Do you have a keyed lock washer? Without one it won't stay light. If you have a keyed washer with a damaged key it won't hold either
"Marriage is a wonderful invention; but then again so is the bicycle puncture repair kit." - Billy Connolly
sarniacycle
Posts: 199
Joined: 17 Jun 2012, 1:19pm

Re: Self-loosening threaded headset mystery...advice appreci

Post by sarniacycle »

Nope, no keyed washer but no 'slot' for one either so not an option! And it's a 15yr old bike I guess (though mine for only 7 months or so) so don't think it can always have been a problem.

But maybe this is a case of all these little things together contributing

eg

long steerer so lots of spacers so lots of potential wiggle + no keyed washer + top adjusting cup that doesn't match top fixed cup so without bearings in a cage things can slide around more...

Thanks folks, I might be coming towards a solution: buy some cages (since I threw the old ones out, thinking I was improving things!) and shove them back in, see what happens..
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531colin
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Re: Self-loosening threaded headset mystery...advice appreci

Post by 531colin »

Well, I don't think its the original fork at that length, so its not all a 15 year old bike.....and I worry that the headset isn't all a matching set either..?
re. the keyed washer...they all have backlash too, so they don't really help much
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cycleruk
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Re: Self-loosening threaded headset mystery...advice appreci

Post by cycleruk »

Is that an "ahead" adapter stem? Although that shouldn't be a problem.
I have an 16 year old bike with a spacer to give me extra height and has never been a problem.
Make sure the top locknut isn't biting down on the steerer tube top.
Check that all the threads are in good condition.
Perhaps you will have to use more force when locking off the headset with all the spacers in there. :roll:
Possibly replace with just one large spacer like I have.
You'll never know if you don't try it.
Brucey
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Joined: 4 Jan 2012, 6:25pm

Re: Self-loosening threaded headset mystery...advice appreci

Post by Brucey »

some points;

1. -the locknut will always push the threaded race downwards, so you need to allow for that when setting the headset up

2. -the procedure is to tighten the locknut down with the headset set to be slightly slack, then back off, adjust the threaded race a tiny amount (about 1/30th of a turn) tighter, then retighten the locknut. Repeat as necessary. The first time there is no slack with the locknut tight, that is the correct adjustment.

3) The locknut needs to be tight to about 30ftlbs or so.

4) If the thing persistently works loose by unscrewing, it is OK to use a little Loctite on the parts. (I have even experimented with hideous mixtures of Loctite and copper-ease...)

5) Although a single long spacer is best, all those spacers you have are OK provided the stem still reaches down below the threaded portion of the steerer.

6) A loose ball headset that is impossible to adjust is sometimes caused by a few of the balls sitting on 'the wrong shoulder' on the crown race. With some headsets it is almost impossible to eliminate this if the parts are allowed to move in the wrong way before the threaded race is fitted. To avoid the balls moving to the wrong place, stick the balls in the lower cup with grease, then bring the crown race up from below, and do not allow the races to become even slightly separated again before fitting the threaded race, if necessary by using a bungy cord or something.

7) too many balls will also make for a headset that won't adjust properly.

8 ) if the frame isn't prepped perfectly or the headset parts are fitted skew, that will not allow good adjustment either.

cheers
-------------------------------------------------------------------------------
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
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NATURAL ANKLING
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Re: Self-loosening threaded headset mystery...advice appreci

Post by NATURAL ANKLING »

Hi,
The threaded locknut can be shouldered inside so that the lock nut is a close fit on the stem, sometimes has a seal, keeps dirt out/ asthetics (smaller diameter than the threaded portion of nut) if the length of thread above spacers before the lock nut goes on is longer than the internal threaded portion of lock nut then the shoulder is fouling the top of steerer tube :!:
Worth checking, if so just file a mm or two of the top of steerer tube.
NA Thinks Just End 2 End Return + Bivvy - Some day Soon I hope
You'll Still Find Me At The Top Of A Hill
Please forgive the poor Grammar I blame it on my mobile and phat thinkers.
tooley92
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Re: Self-loosening threaded headset mystery...advice appreci

Post by tooley92 »

Would be interested to see what the bottom race of that headset looks like?

It almost looks like the race at the top is a bottom race, although surely it wouldn't fit together like that would it?

On every headset that I have the top race that fits into the frame is very shallow and the threaded adjustable race fits closely over that.
Remember folks 'A pessimist is just an optimist with experience!'
sarniacycle
Posts: 199
Joined: 17 Jun 2012, 1:19pm

Re: Self-loosening threaded headset mystery...advice appreci

Post by sarniacycle »

Thanks again all - if I get an evening this week I'm going to tinker in light of what you've said. I might report back or ask for more advice but right now I'm very grateful what you've offered - plenty to think about. Of course I could just take it to a bike shop but the beauty of this site, and your help, is that you learn something and get better at it and that would be harder to come by if I just got someone else to do the dirty work.

Thanks again, much appreciated.

Adam
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