Carbon forks

Jay dubbleU
Jay dubbleU Posts: 3,159
edited March 2010 in The workshop
Twice I've hit potholes at speed on the Genesis and each time there had been a loud bang - checked the carbon forks but no signs of damage and the bike seems as normal - is this usual ? I keep thinking about things like catastrophic failure

Comments

  • nicklouse
    nicklouse Posts: 50,673
    what forks are they?

    and make sure the headset is fine.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • Jay dubbleU
    Jay dubbleU Posts: 3,159
    Managed between a quarter and half turn on all the bolts on the headset - hopefully that has cured it - cheers Nick
  • Radioactiveman
    Radioactiveman Posts: 964
    All the bolts?

    Do you mean the stem, headset usualy only has one bolt for preloading the bearings and overtightening is not recommended

    I think normal practice is to tighten the single bolt in the stem camp until no play can be felt in the fork then tighten the stem to the steerer.

    I am sure someone will be able to confirm/deny this
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  • nicklouse
    nicklouse Posts: 50,673
    Jay dubbleU wrote:
    Managed between a quarter and half turn on all the bolts on the headset - hopefully that has cured it - cheers Nick

    as above arrrrggghhhhh nooooooo

    this covers a full service but it may give a better understanding of why you may have just not changed anything at all.

    http://www.parktool.com/repair/readhowto.asp?id=65
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • Jay dubbleU
    Jay dubbleU Posts: 3,159
    OK some confusion here on my part - I tightened the bolt on top of the headset by a quarter turn - I could have tightened it more but did not want to overtighten. I tightened the two bolts holding the riser to the stem by a quarter. I then tightened the four bolts which fastened the handlebars to the riser - these were quite loose and I tightened them by half a turn each - I adjusted these just after I bought the bike and may not have tightened them enough - it may have been this moving fractionally that caused the noise when I hit the pothole
  • nicklouse
    nicklouse Posts: 50,673
    i hope you undid the two stem bolts before you tried to tighten the top bolt.

    Or you will have just lifted the compression nut in the steerer and not actually tightened the headset. (presuming it needed it).
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • Jay dubbleU
    Jay dubbleU Posts: 3,159
    Yes - I did a basic bike maint course that taught me that
  • nicklouse
    nicklouse Posts: 50,673
    Jay dubbleU wrote:
    Yes - I did a basic bike maint course that taught me that
    sorry but it has been know for people who are used to the old quill type stems to get it wrong.

    and reading your words i was fearing the worst. :wink:
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • desweller
    desweller Posts: 5,175
    Regarding the one-way nut in the steerer, I don't suppose anyone has quantified what the effective spring rate is of the nut so people can relate bearing preload to top cap bolt torque?
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  • nicklouse
    nicklouse Posts: 50,673
    DesWeller wrote:
    Regarding the one-way nut in the steerer, I don't suppose anyone has quantified what the effective spring rate is of the nut so people can relate bearing preload to top cap bolt torque?

    err there is not setting.

    just adjust till play has gone.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown

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