Threadless Headset is loose

[hooverone]

I have never had a bike with a threaless headset before, and on my mountain bike the headset is loose.

If you grab the front brake and then push foward on the bike I can feel the headset rocking back and forth like it is loose.

To tighten this do I just tighten the cap on the top of the stem?


Jim

[eddief]

I have one threadless and 3 threaded bikes and I can never remember which bolt(s) to deal with in what order.

from the Park website:

Begin by removing the adjusting bolt in the center of the steering column. Next, remove the top cap. There may be a star-shaped nut or other fittings inside the steering column. The bolt threads into this fitting and pulls on the fork against the headset bearing surfaces, which acts to tighten the adjustment. Note the height of the steering column relative to the stem. It should be about 3mm (1/8") below the level of the stem. The stem needs to press down on the spacers in order to adjust the bearings. If the steering column is level with the top of the stem, another spacer is needed below the stem.
Remove bolt and top cap to inspect steering column. Lubricate adjusting bolt and re-install cap and bolt by hand only. DO NOT TIGHTEN.
Loosen stem bolt(s) that secure stem to the steering column. Lubricate these bolts if they are dry. NOTE: DO NOT LUBRICATE INSIDE STEM OR ON STEERING COLUMN SURFACE.
Wiggle the stem side to side to see that it is loose. If the stem is jammed or rusted frozen to the steering column, no adjustment can be made.
Align stem straight to wheel and gently secure the top bolt. Stop when any resistance is felt.
Tighten stem bolt(s).
Check for play by pulling back and forth on fork. Turn the handlebars in different directions while checking for play. There may be play at this early setting. Use care when grabbing suspension forks, because the legs may have play. Grab upper portion of fork.
To adjust bearings, LOOSEN STEM BOLT(S).
Turn adjusting bolt in center cap only 1/8th turn clockwise.
Secure stem bolts, check for play again.
Repeat adjustments as above until play disappears. Remember to loosen stem bolts before turning adjusting bolt in cap.
Check alignment of stem and tighten stem binder bolts fully.
NOTE: Another test of play is to place the bike on ground and grab the front brake tightly. Press downward on the handlebars and rock the bike forward and back. A knocking sensation may indicate a loose headset. In effect this does the same thing as grabbing and pulling on the fork. However, play in the brake caliper arms may also cause a knocking. Front suspension forks may also have play in the legs, which can cause a knocking. If the adjustment seems very tight, there may be other problems in the headset. Bearing surfaces may be worn out, or the ball bearing retainers may be upside down, or a seal may be improperly aligned. If play always seems present no matter the adjustment, the steering column may be too long for the stem and top cap. Add spacers beneath stem in this case.
Bearing Adjustment and "Feel"
Bearing surfaces are made from hardened steel. The surfaces are cut typically by grinding. Round ball bearings roll on the curved surface of the cup and cone. Even the highest quality bearing surfaces will have slight grinding marks. In the left image below is a high quality cone magnifed two hundred times. Notice the parallel marks from the grinding stone. Also note a slight pit from wear. The right hand image is a bearing magnifed the same amount. It does show some surface marking, but is generally smoother than the cone or cup. Bearing surface smoothness will vary between manufacturers and between models. Some bearing system will simply "feel" smoother because they are smoother. This is why it is difficult to adjust by using a subjective feeling of smoothness. Generally, adjust bearings for the loosest setting that has no knocking or play, regardless of this relative smoothness.

[pdonk]

Caution, it might not be the headset you are feeling that is loose, it could be the bushings in your fork.

To check, rock your bike with your brakes on, but put one hand around the upper cup to see if you can feel it move. If you feel it then it is the headset, if not it is your fork.

[Dave]

Loosen the steering tube clamp bolts on the stem. Tighten the top cap until you feel some increased drag when the fork is turned, then loosen the top cap bolt 1/8-1/4 turn, just enough to eliminate the drag. Retighten the steering tube clamp bolts on the stem.

All that rocking the bike stuff is not necessary and it does not work on integrated headsets. If you never tighten the top cap enough to cause some increased drag, you don't really know that you've reached zero clearance.

[CalfeeFly]

Go to a good mechanic...headsets are nothing to play around with...a little knowledge can be deadly...

[BarryG]

All that rocking the bike stuff is not necessary and it does not work on integrated headsets. If you never tighten the top cap enough to cause some increased drag, you don't really know that you've reached zero clearance.
True - if you adjust the top cap to just take up the play when rocking, you will likely end up with headset bearings that are adjusted too loose and you WILL feel it, especially on rough roads.

[gdw]

You don't need to waste your money at the LBS. Threadless headsets are easy to maintain and only require a couple hex wrenches and a little common sense to adjust. Just make sure that it is actually the headset that is loose, follow pdonk directions, and adjust it like dave advises if it is. Make sure the bolts are tight and you're all set.

[hypnospin]

when it come to bearing adjusment, overtightening can=ruined compnents.
but you can learn lots at
www.parktool.com/repair_help/FAQindex_shtml


You don't need to waste your money at the LBS. Threadless headsets are easy to maintain and only require a couple hex wrenches and a little common sense to adjust. Just make sure that it is actually the headset that is loose, follow pdonk directions, and adjust it like dave advises if it is. Make sure the bolts are tight and you're all set.

[gdw]

I was referring to the bolts on the stem which secure it to the steering tube. I think dave did a pretty good job describing how to tighten the headset. The Park info eddief posted was great but dave's instructions were concise and adequate.