Bicycle Mechanics - Headset adjustment

I've just serviced my 1979 road bike. I'm having trouble getting the headset adjusted correctly. If I adjust it so it moves freely it's too tight when I tighten the lock nut if I leave it a little loose it rocks back and forth after tightening the lock nut. Time for a new headset or more tries on adjustment?

I've just serviced my 1979 road bike. I'm having trouble getting the headset adjusted correctly. If I adjust it so it moves freely it's too tight when I tighten the lock nut if I leave it a little loose it rocks back and forth after tightening the lock nut. Time for a new headset or more tries on adjustment?

I'm assuming that this is a threaded steerer. I think the problem is in your adjustment technique. Make sure to hold the adjustment steady while tightening the locknut. The keyed washer between them (You do have a keyed washer between them, right?) is not precise enough to keep the adjustment intact while you tighten the locknut. If you don't have a keyed washer in there, then holding the adjustment steady is even more critical.

You will have to set the adjustment, then apply force counterclockwise while you tighten the locknut. Otherwise the adjustment ring will turn clockwise slightly screwing up the adjustment. It takes some finesse. The other way to do it is to set the adjustment, then back it off a touch, and then tighten the locknut. You're in effect compensating for the fact that tightening the locknut will turn the adjustment a little bit.

It's also possible that your bearings have worn little "stops" in the cups, since a headset spends most of it's life within a few degrees of straight ahead. (This is sometimes called "indexed steering".) It makes adjusting the headset close to impossible. You can get away without replacing the headset if you have clipped bearings in there by going to "loose" (i.e. not in a clip) bearings. You will be putting more bearings in, and they'll be hitting the cups in different places, which gets around the wear points.

That may be a confusing description, but if you search on the forums for "loose bearings" you'll find better explanations. I need more coffee...

Kotts

Kotts is right about your adjustment technique. Rather then type a whole bunch of stuff about how to do it, Park Tools has this (http://www.parktool.com/repair/readhowto.asp?id=127). Read it twice before you proceed;)

Unfortunately, Park doesn't mention the need to secure the stem in place prior to doing a threaded HS adjustment. Tighten it to the same torque as required prior to bke usage. This method is listed in better HS manuals (Campagnolo, Edco and Stronglight.) Failing to initially tighten the stem may result in a slight deformation of the steerer tube after bearing adjustment with unintended additional bearing pressure. Best technique is to fully tighten the stem prior to adjustment.

But what about subsequent stem adjustment, you ask? It was a little too high or low or not perfectly straight. I've not seen any reference to the impact on a final HS adjustment where a stem is adjusted following proper HS install. Is it a 'best practice' to readjust the HS whenever changing the stem placement (higher or lower, left or right) or is this not required? Remember, I'm trying to outline a 'best practice' and not what a quick method may dictate.

Steve

I see no reason a quill stem adjustent would have any effect on a threaded headset adjustment. The stem causes no longitudinal thrust on the steerer, just a radial load and the expander is (or better be) well below the upper headset race and well above the lower one. How can it make any difference?

Just one other point to add to the good advice so far: if you get it adjusted right and it feels good (free of play, free-turning) in the straight ahead position, check it at other positions to make sure it feels the same at all positions. If it doesn't, take another look at the bearing faces - either the frame needs to be align-bored and faced, or the bearing faces really are not good enough.

I've had the quill stem problem, and you just have to re-adjust the headset after you get the stem in place and torqued. On smaller frames you really don't always have the freedom to place the stem vertically so the clamp is well away from the threads.

Road Fan

You need TWO headset wrenches in order to adjust and lock down a headset properly. Or at least one headset wrench and a BIG adjustable wrench or channel-locks or pipe-wrench. The thin headset wrench is critical to hold the adjustable cup steady as you tighten down the lock-nut.

Actually the procedure that really works 100% of the time is to unscrew the adjustable cup upwards into the locknut that you're tightening down. This pushes the two parts together and generates the thread-friction that locks the parts into place. If all you do is tighten the lock-nut, it's possible to press the locknut down into the keyed-washer only, but the adjustable cup would still be loose underneath.

This might be a dumb question, but did you also lube the headset? Mine was doing the same thing last week - couldn't get it to stop rocking without being very sticky. Turned out it was in dire need of a re-lube. Whoops.

Might also get rid of the bearing retainers if you have them, they seem good at nothing but collecting crud and creating "indexed" steering.

Unfortunately, Park doesn't mention the need to secure the stem in place prior to doing a threaded HS adjustment. Tighten it to the same torque as required prior to bke usage. This method is listed in better HS manuals (Campagnolo, Edco and Stronglight.) Failing to initially tighten the stem may result in a slight deformation of the steerer tube after bearing adjustment with unintended additional bearing pressure. Best technique is to fully tighten the stem prior to adjustment.

But what about subsequent stem adjustment, you ask? It was a little too high or low or not perfectly straight. I've not seen any reference to the impact on a final HS adjustment where a stem is adjusted following proper HS install. Is it a 'best practice' to readjust the HS whenever changing the stem placement (higher or lower, left or right) or is this not required? Remember, I'm trying to outline a 'best practice' and not what a quick method may dictate.

Steve

Do you realize we are talking about a threaded fork? :twitchy:

HillRider said: "I see no reason a quill stem adjustent would have any effect on a threaded headset adjustment. The stem causes no longitudinal thrust on the steerer, just a radial load and the expander is (or better be) well below the upper headset race and well above the lower one. How can it make any difference?"

All I can offer is the specific advice in the Campy Super Record HS and latest Record HS instructions. They indicate: SR, "Only when you have fitted the handlebar stem to the frame, adjust the headset." And Record, "Adjustment: Fit the handlebar stem before adjusting bearings, so as to avoid any change in adjustment due to deformation of the steerer column."

Tightening the stem wedge causes a small deformation and consequential shortening of the steerer column, resulting in an unintended additional compression on the HS bearings. They probably have enough experience in these matters to include this step in the HS install and adjustment procedure.

Do you realize we are talking about a threaded fork? :twitchy:

Yes, absolutely.

HillRider said: "I see no reason a quill stem adjustent would have any effect on a threaded headset adjustment. The stem causes no longitudinal thrust on the steerer, just a radial load and the expander is (or better be) well below the upper headset race and well above the lower one. How can it make any difference?"

All I can offer is the specific advice in the Campy Super Record HS and latest Record HS instructions. They indicate: SR, "Only when you have fitted the handlebar stem to the frame, adjust the headset." And Record, "Adjustment: Fit the handlebar stem before adjusting bearings, so as to avoid any change in adjustment due to deformation of the steerer column."

Tightening the stem wedge causes a small deformation and consequential shortening of the steerer column, resulting in an unintended additional compression on the HS bearings. They probably have enough experience in these matters to include this step in the HS install and adjustment procedure.

Makes sense to me. I have never adjusted a headset without the quill installed.

Makes sense to me. I have never adjusted a headset without the quill installed.
Neither have I but that's because it's the only way to be able to "rock" the bike with the front brake locked to determine when the play is just gone. Again, I'm convinced the steerer longitudinal "distortion" from tightening the stem expander has to be microscopic.