Bicycle Mechanics - Is something wrong with my headset?

The bike is a 2005 Lemond Croix de Fer.

When I hold the front brake and rock the bike back and forth, there's a low 'clunk' sound that the headset emits. It's not very audible, but I can feel the vibrations in the frame. I've also felt it while riding, when pressing and releasing the front brake.

Is it likely that the headset needs adjustment? Would that be something I could do myself, or does it require special tools?

Thanks,
-Gabe

Yes, your headset is too loose (it has some play in the bearings). An adjustment is what you need. If you have a threadless headset, then you need no tools other than allen wrenches. If you have a threaded headset, then you need cone wrenches (very thin metric wrenches). Chances are you have a threadless headset, since it's a high-end 2005 road bike.

Go to parktool.com and look at the repair help section for a great guide on how to adjust your headset.

Also assuming a "threadless" headset, the procedure is:

1. Loosen the bolt(s) that clamp the stem to the steerer. Be sure thay are loose enough that the stem is free to turn. You cannot adjust the headset if the srem is still tight on the steerer.

2. Gradually tighten the allan bolt located in the center of the steerer's top cap. Lock the front brake and try to rock the bike while tightening this bolt. Continue until the headset play completely disappears. Some headsets actually specify a preload of 8 to 20-inch pounds.

3. Center the stem and tighten its clamp bolts firmly.

Loosen the bolts that clamp the stem to the steerer tube.

Tighten the bolt on the stem clamp to remove the play in the headset.

Make sure your stem is straight and tighten the clamp bolts.

get it fixed ASAP!!!
It will ovalize the head tube eventually if riden like this.

get it fixed ASAP!!!
It will ovalize the head tube eventually if riden like this.I'm glad I asked!

I'm going to try the adjustments specified by HillRider and supcom, and report back.

Thanks!
-Gabe

I'm glad I asked!

I'm going to try the adjustments specified by HillRider and supcom, and report back.

Thanks!
-Gabe
Do read that parktool page!!! You need to know how to feel when the adjustment is just right, and it can be a bit tricky if you haven't done it before.

I did the following:

1) Held the front brake and rocked the bike. Felt knocking.
2) Loosened stem bolts until I could rotate the handlebars independantly of the fork. There was still some resistance when doing this, but it was free enough to rotate.
3) Held the brake and rocked the bike. The knocking was gone (!)
4) Tightened the bolt on top of the stem (about 1/6 revolution)
5) Aligned the stem and tightened the stem bolts
6) Held front brake, rocked bike. No knocking.

Is there a way to check that I did not overtighten, or otherwise mess something up? I could also go back and follow the more involved parktool instructions if my simplistic method might cause problems.

I did the following:

1) Held the front brake and rocked the bike. Felt knocking.
2) Loosened stem bolts until I could rotate the handlebars independantly of the fork. There was still some resistance when doing this, but it was free enough to rotate.
3) Held the brake and rocked the bike. The knocking was gone (!)
4) Tightened the bolt on top of the stem (about 1/6 revolution)
5) Aligned the stem and tightened the stem bolts
6) Held front brake, rocked bike. No knocking.

Is there a way to check that I did not overtighten, or otherwise mess something up? I could also go back and follow the more involved parktool instructions if my simplistic method might cause problems.
Your method is good. Well done! Basically, you've overtightened if it's much harder to rotate the stem/bars than it was before you did the adjustment (when it was loose).

The optimal condition for any bearing on a bike is: Zero play, and as little friction as possible.

Your method is good. Well done! Basically, you've overtightened if it's much harder to rotate the stem/bars than it was before you did the adjustment (when it was loose).

The optimal condition for any bearing on a bike is: Zero play, and as little friction as possible.

+1

When rotating the stem, I can now feel a slight rubbing - not really forceful resistance, but definitely a bit of vibration.

I'm going to try loosening the top bolt a smidgen.

It seems to have worked! No knocking, and no more vibration when turning the handlebars.

Thanks guys!