First Foray Into Threaded Headset Adjustment Gone Wrong

[grognaak]

So, I noticed a knocking when using the front brake. Diagnosed as headset problem and ordered the Park Tool wrenches--fine, everything normal so far. I proceeded to scratch the hell out of the Campy Record headset trying to adjust it, had to go back and forth trying to find the proper tightness way too many times, had no idea how tight to go on the locknut, and ended up scratching paint from the frame when the front brake slammed into downtube. This in spite of watching several YouTube videos and reading Zinn several times. I don't think I went too far tightening the race, but I'm not sure. The front wheel seems to turn pretty easily and the knocking is gone when the brake is held, but . . .

I'm left wondering . . .

How do I avoid scratching the hell out of the headset? If the wheel doesn't return perfectly to center when pulled to the left but goes a little past center and sticks there when the bike is held up and tilted forward, did I screw up the headset? How tight is the locknut supposed to be? Is it easy to screw up something up by going too hard on the locknut? Can a steel frame be damaged or is it limited to the headset if you have fists of ham? Should I use nail polish to touch up the frame?

Thanks!

[Mark McM]

I have to admit that I often end up marring the faces of the locknut a little bit when I adjust the headset, but I find that better quality tools are better in this regard.

Obviously you don't want the headset to be too loose or too tight. You want a little bit of preload on the bearings, but the headset should be free to turn. For too loose, I lift the bike up by the fork drop outs so that the weight is balanced completely on the rear wheel. I then apply and up and down force on the dropouts and feel for any looseness or play. If any play is felt, the bearings are too loose. This test is potentially better than "lock the front brake and rocking the bike forward and back" test, because it eliminates any flex and play in the brake and front hub bearings.

For too loose, lift the bike straight up vertically (both wheels an equal distance off the ground), and gently tilt the bike to the left and right a few degrees. The fork should readily turn in response to even the smallest change in the tilt of the bike. If a large change in tilt is required for the fork to turn, the bearings are too tight.

There could be several reasons that the steering angle of the fork is biased to one side when the bike is perfectly vertical (not tilted to one side or other). The most common cause a little stiffness in the brake/derailleur cables. If the bias angle is small, and if the fork easily turns (in either direction) when the bike is tilted to the side, then this should not be a problem. If the bias angle is large, then you'll probably want to address the length/routing of the cables. Another possible cause is an notched headset (and that the notches are off-center). In this case, you can usually feel for the presence of notches by gently turning the fork by hand. Typically, there will be several notches, equal distant apart. A notched headset should be replaced. A further possible cause is a poorly faced head tube, causing the top and bottom races to be non-parallel. This can be detected by rotating the fork completely around, and noting if bearings get tighter or looser at different orientations. If the bearing preload changes as the headset is rotated, the headtube should be faced.

[Ken Robb]

Originally Posted by Mark McM

I have to admit that I often end up marring the faces of the locknut a little bit when I adjust the headset, but I find that better quality tools are better in this regard.

Obviously you don't want the headset to be too loose or too tight. You want a little bit of preload on the bearings, but the headset should be free to turn. For too loose, I lift the bike up by the fork drop outs so that the weight is balanced completely on the rear wheel. I then apply and up and down force on the dropouts and feel for any looseness or play. If any play is felt, the bearings are too loose. This test is potentially better than "lock the front brake and rocking the bike forward and back" test, because it eliminates any flex and play in the brake and front hub bearings.

For too loose, lift the bike straight up vertically (both wheels an equal distance off the ground), and gently tilt the bike to the left and right a few degrees. The fork should readily turn in response to even the smallest change in the tilt of the bike. If a large change in tilt is required for the fork to turn, the bearings are too tight.

There could be several reasons that the steering angle of the fork is biased to one side when the bike is perfectly vertical (not tilted to one side or other). The most common cause a little stiffness in the brake/derailleur cables. If the bias angle is small, and if the fork easily turns (in either direction) when the bike is tilted to the side, then this should not be a problem. If the bias angle is large, then you'll probably want to address the length/routing of the cables. Another possible cause is an notched headset (and that the notches are off-center). In this case, you can usually feel for the presence of notches by gently turning the fork by hand. Typically, there will be several notches, equal distant apart. A notched headset should be replaced. A further possible cause is a poorly faced head tube, causing the top and bottom races to be non-parallel. This can be detected by rotating the fork completely around, and noting if bearings get tighter or looser at different orientations. If the bearing preload changes as the headset is rotated, the headtube should be faced.

Thanks for this thorough explanation!

[grognaak]

Thank you! What are the consequences of prolonged riding with a too loose or too tight headset?

[palincss]

A damaged headset.

[paredown]

When they were steel, the chances of damage was less. I have resorted to taping the wrench faces now that everything is alu.

The other 'trick' is to tighten the bottom nut down a little tight, then the hand tighten the top nut down to that. Then hold the top nut steady, and back the bottom nut up tight to the top one. It seems easier to hold the clearance constant, since when you cinch down on the top nut, it does tend to compress both nuts down, and alter the clearance that you have tried to leave.

A second comment--sometimes if it feels as if there is no half-way between too tight and too loose (at which point i usually take the whole thing apart to ensure that I have not had a brain freeze and installed something incorrectly)--and particularly if it seems the point at which it binds is different side to side--is to check carefully that the cups are seated squarely in the head tube, and down tight to the frame. If the whole gizmo is not squarely compressing as you tighten, the binding will show up as a slight difference.

Third comment--if the headset is well-used and been left too loose, you also might get uneven feeling because of ball-bearing wear (also true just from wear(; if it had been left too tight you could get brinelling--a series of ball bearing shaped divots in the races that makes if feel 'clicky' when tight, so check balls and races carefully while assembling.

[icepick_trotsky]

Riding with a poorly adjusted headset can also risk damaging the threads on your steertube, which can wreck the fork. I've done this before.

[jemdet]

Don't worry about the locknut until you have the preload correct. Like others have said - make sure there's no play but that the wheel can turn freely. Keyed washer b/w the locknut and adjustable nut.

Use one wrench to keep the adjustable nut from turning while you tighten the locknut with a second wrench. Only the locknut should be turning. Make it really tight. Tight tight. You're pushing three flat pieces of metal against one another. I'm not sure that John Henry could overdo it.

[donevwil]

Once I picked up one of these marring the locknut became history.

[Mark McM]

Originally Posted by jemdet

Don't worry about the locknut until you have the preload correct. Like others have said - make sure there's no play but that the wheel can turn freely. Keyed washer b/w the locknut and adjustable nut.

Adjusting the headset pre-load on a threaded headset is often an iterative process. Due to clearances in the threads (which are required, or else you wouldn't be able to screw threaded parts together), the pre-load with the locknut loose will be different (looser) than with the locknut tightened. This is one of several reasons that threadless steerers/headsets are better.

[weisan]

chicks dig guys with scars...

[Hindmost]

Aluminum cups and lock ring? Yeah it's a problem.

Just know during initial adjustment there's going to be several trial and errors so don't take things to full tightness, just very light tightness at first. Try not to use much force on the cup, just hold the position of the cup with a wrench and only move it after releasing the force from the lock ring. And only put full force on to the lock ring when finalizing adjustment. The slotted washer should prevent rotation of the cup for the most part. (Make sure the slotted washer can move freely up and down the steer tube. Carefully file the inner surfaces of the washer or clean up the steer tube if it doesn't.) Full force just has to be pretty firm, not wicked firm. The size of the wrenches give the impression that you use mega-torque. If there's space try putting masking tape on the faces of the wrench flats.

[Oxford_Guy]

Originally Posted by donevwil

Once I picked up one of these marring the locknut became history.

This tool doesn't seem to be available anymore, is there anything currently available that is as good (espc. on an aluminium headset)?

[speedevil]

The simplest way to check the headset preload on a threaded steerer is to apply the front brake and move the bike forward and backward. When there is no movement of the fork, the preload is set correctly.

This presumes that you're tightening the cone and removing play, because if it's already too tight you won't have any fork movement either.

I use cellophane tape on the top nut to prevent marking it when tightening it down. If you hold the cone with the headset wrench and snug the top nut down, the preload shouldn't change much if at all. This presumes that you have the keyed washer on top of the cone.

Riding with the headset loose will cause "brinelling" (I think that's the correct term) and the bearing balls being much harder than the alloy cup races will make tiny indentations in the races. As a result the bar movement can feel "notchy". If the bearing balls are in a retainer, sometimes you can extend the headset life by using loose balls without the retainer.

[ultraman6970]

I been looking for that headset wrench for the longest time.

What surprise me is that everything that is in the market, eventhought should be at least close to specs, they arent... always lose... use them 10 times and they get worse...

It is what it is tho...