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Fork Steerer -- too much showing above stem?

edited June 2007 in Workshop
I'm having trouble getting the headset stack on my Record Hiddenset to compress -- It needs to be really tightened to get no play, then works loose over a ride -- a mm play maybe, but it's very noticeable.

The stem is resting on top of the TTC -- no spacers in between, but I do have 40-50mm steerer showing above the stem. Someone mentioned that having too much steerer showing can cause these problems. I don't want to go to the arseache of cutting down the steerer again if I can help it.

Any thoughts, suggestions?

Forks are Dedacciai Black Drive -- carbon steerer, correct bung used.

TIA,

Cheers,

Tim

http://vizarch.blogspot.com

Posts

  • Hi, I have this problem on one of my bikes and that one has not spacers, Im sure its the bung sliding up inside the steerer. My other bike that does not have this problem I superglued the bung to make sure it did not move
  • Cheers --

    I think you may be right about the bung slipping. Superglue seems a bit of a drastic solution, though...!

    Cheers,

    Tim

    http://vizarch.blogspot.com
  • MarktaMarkta Posts: 767
    quote:Originally posted by TimDanaher

    Cheers --

    I think you may be right about the bung slipping. Superglue seems a bit of a drastic solution, though...!

    Cheers,

    Tim

    http://vizarch.blogspot.com



    There are expander bungs which have perforated edges (a bit like a cheese grater) so that it grips to the steerer tube better. I think M:Part make one (œ10)

    http://mrkta.myphotoalbum.com/albums.php
  • msb123msb123 Posts: 274
    i'm not sure if i followed your description, but i have always understood that the top of the steerer needs to be 3/4 mm below the top of the stem (or spacer if there are spacers above the stem - which it sounds like you have) - otherwise there is no space to compress

    try putting enough spacers in so the top of the steerer is 4 mil below the stem/spacer - then see if it will tighten

    or ignore me if you've done all this
  • msb123msb123 Posts: 274
    ps - 3/4 is meant to mean 3 or 4, not three quarters of a mil!
  • Thanks, all --

    The bung I have is of the 'knurled' variety, and I did put an extra 2.5mm spacer on, just to be sure...same result.

    On another thread someone mentioned this:

    http://www.use1.com/products/ringo_star/index.php

    Anyone know what it's supposed to do?

    Cheers,

    Tim

    http://vizarch.blogspot.com
  • maddog 2cpmaddog 2cp Posts: 3,134
    there can only be two explanations

    1. The headset wasn't preloaded enough to begin with. Either you don't have enough space between the spacer and the top of the steerer or your SFN/bung is slipping.

    2. The headset was preloaded correctly but the stem itself is slipping as you ride, leading to looseness.

    Sounds like #1 to me.

    Drop bars are a historical accident...... discuss
    Drop bars are a historical accident...... discuss
  • maddog 2cpmaddog 2cp Posts: 3,134
    you are undoing the stem bolts when you're attempting to preload the headset...............

    Drop bars are a historical accident...... discuss
    Drop bars are a historical accident...... discuss
  • quote:Originally posted by maddog 2

    you are undoing the stem bolts when you're attempting to preload the headset...............


    Errr..yes.

    When you say 'preload' I've been putting weight on my historical accidents while tightening up the cap...

    Cheers,

    Tim

    http://vizarch.blogspot.com
  • andrew_sandrew_s Posts: 2,511
    It (the ringo-star) is effectively a variable-thickness spacer. It goes below the tightly clamped stem, and you adjust the bearing using a 4mm allen bolt (next size smaller than bottle cage) to expand or contract the thickness of the spacer, rather than by screwing the top cap up or down against a fixed bung or start nut.

    If your headset is working loose, it can't be the bung slipping unless you haven't tightened up the stem clamp properly. You should be able to ride normally having adjusted the bearing, clamped the stem and removed the top cap and bung entirely.
    An alternative source of the problem could be that the cups/bearing seats on the upper or lower head tube or the fork crown haven't been pressed home properly.
  • Actually, finally got around to solving this...

    Maddog's suggestion about preloading the races properly got me thinking -- the bung is censored and is causing the problems, but the bung isn't neccessary at all after the stack's been tensioned.

    So, I just made a makeshift windlass -- looped some cord under the fork crown & over the top of the stem, tied it, used a tyre lever as the handle, few twists -- the bearing tightened up nicely. The hook on the tyre lever can be used to 'lock' the windlass while you tighten up the stem.

    Job done!

    The bung now simply holds the top cap in place, as decoration.

    Cheers,

    Tim

    http://vizarch.blogspot.com
  • jpembrokecpjpembrokecp Posts: 1,968
    Just in case this isn't a wind up.....

    The top of the steerer must always be a few mm below the level of the top of the stem. Trying to tighten up a headset with steerer protruding above the level of the stem is equivalent to attempting to pull up a drain cover whilst standing on it. The headset cap must rest on stem or spacer, not steerer, or it can't do it's job. Think about it. And you don't need to cut down the steerer, just add a couple of spacers below the stem to raise the level of teh stem above the top of the steerer.

    and bungs for carbon steerers can be a bit cr*p but they do work usually.

    and please don't use superglue.

    well, yes and no......but mainly no.

    well, yes and no......but mainly no.
  • Oh well, I must be completely mistaken in the fact that I now have a play-free headset with preoperly seated bearings. Silly me.

    Cheers,

    Tim

    http://vizarch.blogspot.com
  • jpembrokecpjpembrokecp Posts: 1,968
    Sorry, I think I got the wrong end of the stick. The 40-50mm of steerer that protrudes above the level of the stem does have spacers on it doesn't it? If that is the case then I take back what I said. Just as long as your top cap is not touching the steerer but is resting on either the top iof the spem or a spacer then your set-up is fine.

    well, yes and no......but mainly no.

    well, yes and no......but mainly no.
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