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Boring Question - Sorry

markdavidhillmarkdavidhill Posts: 279
edited January 2012 in Workshop
Alloy handlebars, alloy stem.

What 'Nm' should I achieve to clamp the bars which currently creak a bit under power?

Thx.
Team Madison Genesis Volare & Condor Super Acciaio

Posts

  • smidsysmidsy Posts: 5,273
    My Cannondale C2 stem says 4.5 -5.6 on it.
    Yellow is the new Black.
  • sungodsungod Posts: 13,358
    depends on the stem, it's often marked on it

    i'd try taking the bars off, cleaning all the clamping surfaces, stem, bars, faceplate, lightly grease the threads of the bolts, reclamp

    when clamping, do it a bit at a time and try to even the force over the faceplate

    for instance, if it's got four bolts, viewed from front...

    1 - 2
    |....|
    3 - 4

    ...do them up in this order 1 4 2 3, start finger tight, then give each a half turn until you reach enough force to clamp the bars, 5-6Nm is usually plenty

    oh, and have a good look just to be sure there isn't a crack anywhere!
    my bike - faster than god's and twice as shiny
  • markdavidhillmarkdavidhill Posts: 279
    sungod wrote:
    depends on the stem, it's often marked on it

    i'd try taking the bars off, cleaning all the clamping surfaces, stem, bars, faceplate, lightly grease the threads of the bolts, reclamp

    when clamping, do it a bit at a time and try to even the force over the faceplate

    for instance, if it's got four bolts, viewed from front...

    1 - 2
    |....|
    3 - 4

    ...do them up in this order 1 4 2 3, start finger tight, then give each a half turn until you reach enough force to clamp the bars, 5-6Nm is usually plenty

    oh, and have a good look just to be sure there isn't a crack anywhere!

    Thank you. The stem is a Ritchey Pro with 5Nm on it but I wasn't sure if this was pertaining to carbon bars.

    The bars have some sort of 'sticky tape' on them at the point of grip.

    The bolts have not been previously greased. Could I also use a grip paste?
    Team Madison Genesis Volare & Condor Super Acciaio
  • sungodsungod Posts: 13,358
    afaik torque spec on stems is based on the stem itself, if exceeded by too much you risk deforming/cracking/etc.

    for the bolts, just a little grease or anti-seize

    assembly paste on the bars at the clamp point won't hurt, but on alloy-alloy it's really not needed

    i've never had any sticky tape on the clamping area of bars i've used, presumably it's to reduce the clamping force needed, the fact that it's there would put me off applying paste/whatever to it, if the tape is in good condition i'd leave it alone
    my bike - faster than god's and twice as shiny
  • YossieYossie Posts: 2,600
    As above - max of 5Nm, so call it 4. Grease/paste if you want to on the bar stem/bar interface, but not strictly necessary. Copperslip on the bolts, do them up exactly as above.

    FYIW, the lack of grease anywhere probably helped part cause the creaking in the first place.
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