expanding wedge fork bung

stagger
stagger Posts: 116
edited February 2009 in Workshop
The fork I am fitting comes with an aluminium sleeve with a star nut built in, the sleeve to be epoxy'd to the (carbon) steerer.

Should I defo use the alu sleeve ( thats what the instructions say) ?

Or will using an expanding wedge plug be just as good? easier to fit, obviously..

I guess the sleeve/star nut is stronger and less likely to damage the steerer, any thoughts appreciated

ta

Comments

  • gundersen
    gundersen Posts: 586
    no idea of what your talking about.

    got a picture ot two?
  • stagger
    stagger Posts: 116
    Ok, no pics but will try to be clearer:

    I am referring to the way in which the headset is preloaded via the cap bolt.

    This by

    1. the cap bolt bolt enagaing with a star nut inserted into the steerer, in this case the start nut is built into a sleeve which is glued into the steerer,

    2, the cap bolt can engage with a wedge plug that expands within the steerer (like a rawlbolt) when you load it,
  • Mister W
    Mister W Posts: 791
    Carbon is a very directional material so if the steerer hasn't been designed to take a load expanding from the inside then it may fail. Do whatever the manufacturer says.
  • andrewjoseph
    andrewjoseph Posts: 2,165
    A wedge does not damage the inside of the steerer, a star nut does.

    the star nut works by the flanges digging into the material of the steerer.

    the wedge works by expanding against the inside of the steerer. It has a much larger contact area and does not damage the steerer.

    this is why expanding wedges are advised for carbon steerers. Star nuts invalidate the warranty of carbon steerers.
    --
    Burls Ti Tourer for Tarmac, Saracen aluminium full suss for trails
  • stagger
    stagger Posts: 116
    andrewjoseph wrote:
    A wedge does not damage the inside of the steerer, a star nut does.

    the star nut works by the flanges digging into the material of the steerer.

    the wedge works by expanding against the inside of the steerer. It has a much larger contact area and does not damage the steerer.

    this is why expanding wedges are advised for carbon steerers. Star nuts invalidate the warranty of carbon steerers.


    ta, yes I can see your. point. in this case tho, the star nut wont damage the steerer by direct contact, as it bites against an aluminium sleeve which is glued inside the steerer.

    In fact, the warranty seems to say the opposite- use this system only.. I just thought it would be less hassle to use an off shelf expander hence the question
  • Wappygixer
    Wappygixer Posts: 1,396
    If you already have this alloy sleeve glued in place do you have room to fit an expanding plug?
    Also does the sleeve run the full length of the fork steerer?
    Who makes these forks?
    Never seen a system like this.We use the Time method on our forks where by the forks are preloaded by the stem, you them have a conical clamp which sets the final tension for the headset.
  • Frank the tank
    Frank the tank Posts: 6,553
    If the manufacturer is recomending the ues of the alloy sleeve, what is the fit between the mating faces of the sleeve and the steerer tube like and has some epoxy been provided to do the job.

    If you follow the manufacturers method make sure the mating faces have been abraded and de-greased thouroughly. You shouldn't have to make a guess at what bonding agent should be used, it should be provided if it's their recommended way of assembley
    Tail end Charlie

    The above post may contain traces of sarcasm or/and bullsh*t.
  • stagger
    stagger Posts: 116
    Wappygixer wrote:
    If you already have this alloy sleeve glued in place do you have room to fit an expanding plug?
    Also does the sleeve run the full length of the fork steerer?
    Who makes these forks?
    Never seen a system like this.We use the Time method on our forks where by the forks are preloaded by the stem, you them have a conical clamp which sets the final tension for the headset.

    the alloy sleeve is instead of an expanding plug.. Its about 75mm long so will be just at the top section of the steerer, allowing the top cap bolt to enage with the star nut already attached internally in the sleeve ( basically its just a star nut but installed in a sleeve presumably to reinforce and avoid damage to the steerer.

    comes with glue etc to bond it to the inside of the steerer but i cant really see any advantage to it over just a simple wedge plug, think i will just use a wedge plug , definitely less hassle, unless someone can convince me otherewise!

    thx for replies.

    Alpha q forks

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