Headset/Fork problem??

lordlee

Hi All,
Newbie here so please be gentle. My partners Marin Hawk Hill (2001) has a slight wobble from the front end end that is noticeable under braking and also when the front is lifted when stationary and you move the wheel back and forth.
Being new to servicing bikes myself maybe I should just take it to a shop but I like to learn how to do things properly myself so I thought I would reach out for some help.
I have read many threads on here around tighteneing the headset and checking the stem sits 3-5mm higher that the piece of metal it clamps to etc. When I take the top cap off there is nothing there to tighten except that star type thing. Do I have to tighten this up? Could it be some bushings on the fork? Basically what is the best order of troublkeshooting?

TIA

nicklouse

no need to take the cap off as that is what tightens it.

slacken the stem bolts first then tighten the top cap then tighten the stem bolts again.

BG2000

It does just sound like your headset is loose, which should be easy to resolve.

The normal process of tightening is:

1) Completely loosen the stem clamp bolts (the ones that tighten the stem onto the fork steering column)
2) Tighten the bolt in the top cap. Not too much. One method is to gently tighten the bolt while rocking the bike back and forth with the front brake on. As you tighten the bolt, you'll start to feel the 'knocking' of the loose headset go away. Just at the point you can't notice the knocking any more, tighten the stem bolts back up.

You mention the 3mm gap. The top of the stem needs to be at least 3mm higher than the top of the fork's steering column. If it isn't, then the curve of the underside of the top cap will push against the fork's steering column when you tighten its bolt.

lordlee

OK from your posts it sounds like I have already tightened the headset correctly. I slackened the stem and checked its position (its 3mm above the column) and then did the top cap bolt up. Retightended the stem and still had the same problem. What would be my next port of call?

1mancity2

Try to find the "wobble" apply the front brake and push the bike forward, place your fingers against the headset when doing this, can you feel movement? if yes headset is loose.

If no movement check, wheel is tight and secure, front brake caliper is tight.

lordlee

Thaks Mancity. Front brakes are v-brakes and are tight and wheel is tight too. Could it be the headset bearings or would they not allow play even if tight?

1mancity2

If the bearing are shot maybe, do you know if the bearings are still sound?

If you tighten the headset too tight the steering will be come stiff and heavy.

What forks are on the bike?

BG2000

It's quite common for 'cheaper' suspension forks to have some play, and this is most noticeable when you rock the bike back and forth with the front brake on.

In terms of checking the stem/steering tube relative height - try resting the top cap loosely on the stem and check that it's not catching the fork steerer. Slide the stem up a bit and see how the top cap rests, then slide the stem back down an repeat - if the steerer is too long, the top cap will appear to 'float' on top of the stem. Some top caps are very deep and 3mm isn't always enough.

The problem can also be caused by the star spangled nut (the star nut inside the steering tube) being too high, and the top cap ends up tightening against it, rather than it pulling the stem down on onto the bearing cups.

lordlee

It has Rock Shox on but I coudlnt tell you which ones without being by the bike. If I tighten it really tight nothing seems to change and the steering doesnt become heavy?

"The problem can also be caused by the star spangled nut (the star nut inside the steering tube) being too high, and the top cap ends up tightening against it, rather than it pulling the stem down on onto the bearing cups." - This sounds like a likely scenario so how would I fix that.

nicklouse

hit it.

http://www.parktool.com/blog/repair-hel ... stallation

cooldad

If the star nut is too high just knock it in a bit more.
If the steering doesn't stiffen right up when you make it really tight, then it is not tightening up.

lordlee

So if its not tightening up what is my best option?

nicklouse

lordlee wrote:

So if its not tightening up what is my best option?

if the top cap is bottoming on the star nut then yes. if the top cap is bottoming on the steerer no. add another spacer or use a thicker spacer.

deggy92

I built my Boardman pro last year (which was recently nicked, thanks thieves!!) and originally had the same problem. I had left the fork steerer too long so as mentioned previously, when tightened, if I applied my front brake and rocked the bike gently back and forwards, I could see/feel how loose it was. I took a couple of mm off the fork steerer, made sure the top cap wasn't hitting the top of the fork steerer, loosened the stem, leant down on the forks and stem and retightened the stem bolts. Then put the top cap back on and all was good. The top cap doesnt need to be supertight, and if you can feel it pulling the starnut up the fork steerer then replace the starnut.