How tight to clamp a stem on a carbon steertube?

Discussion in 'Cycling Equipment' started by Me, Sep 3, 2003.

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  1. Me

    Me Guest

    Hi, when tigtening the bolts that attach a stem on a road carbon steertube (ie not the headset top
    cap), how tight can I go before damaging the steertube? Or do I even have to worry about causing
    any damage.

    On a cromo steertube, I'd say that the stem's bolts would fail or strip out long before the
    steertube, but when I'm tightening a carbon one (heck even when I'm tightening my carbon seatpost)
    I'm always scared I'll someday hear an almighty CRACK!

    any thoughts?
     
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  2. Me wrote:
    > Hi, when tigtening the bolts that attach a stem on a road carbon steertube (ie not the headset top
    > cap), how tight can I go before damaging the steertube? Or do I even have to worry about causing
    > any damage.
    >
    > On a cromo steertube, I'd say that the stem's bolts would fail or strip out long before the
    > steertube, but when I'm tightening a carbon one (heck even when I'm tightening my carbon seatpost)
    > I'm always scared I'll someday hear an almighty CRACK!

    Whatever kind of stem or steerer you use, it should be tightened enough that if you stand in front
    of the bike and grip the front wheel between your knees, it should take a good firm twist on the
    handlebars to make the stem turn on/in the steerer. If you can't turn the handlebars, it's too
    tight, and it is more likely to cause injury or parts damage in the event of a crash.

    Sheldon "Tight Enough, But Not Too Tight" Brown +-----------------------------------------------+
    | I saw a man pursuing the horizon; | Round and round they sped. | I was disturbed at this; |
    | I accosted the man. |
    | |
    | "It is futile," I said, | "You can never--" |
    | |
    | "You lie," he cried, | And ran on. | --Stephen Crane |
    +-----------------------------------------------+ Harris Cyclery, West Newton, Massachusetts Phone
    617-244-9772 FAX 617-244-1041 http://harriscyclery.com Hard-to-find parts shipped Worldwide
    http://captainbike.com http://sheldonbrown.com
     
  3. I've never heard of that before... is that just for carbon forks?

    Mike http://mikebeauchamp.com

    "Sheldon Brown" <[email protected]> wrote in message
    news:[email protected]...
    > Me wrote:
    > > Hi, when tigtening the bolts that attach a stem on a road carbon
    steertube
    > > (ie not the headset top cap), how tight can I go before damaging the steertube? Or do I even
    > > have to worry about causing any damage.
    > >
    > > On a cromo steertube, I'd say that the stem's bolts would fail or strip
    out
    > > long before the steertube, but when I'm tightening a carbon one (heck
    even
    > > when I'm tightening my carbon seatpost) I'm always scared I'll someday
    hear
    > > an almighty CRACK!
    >
    > Whatever kind of stem or steerer you use, it should be tightened enough that if you stand in front
    > of the bike and grip the front wheel between your knees, it should take a good firm twist on the
    > handlebars to make the stem turn on/in the steerer. If you can't turn the handlebars, it's too
    > tight, and it is more likely to cause injury or parts damage in the event of a crash.
    >
    > Sheldon "Tight Enough, But Not Too Tight" Brown +-----------------------------------------------+
    > | I saw a man pursuing the horizon; | Round and round they sped. | I was disturbed at this;
    > | | I accosted the man. |
    > | |
    > | "It is futile," I said, | "You can never--" |
    > | |
    > | "You lie," he cried, | And ran on. | --Stephen Crane |
    > +-----------------------------------------------+ Harris Cyclery, West Newton, Massachusetts Phone
    > 617-244-9772 FAX 617-244-1041 http://harriscyclery.com Hard-to-find parts shipped Worldwide
    > http://captainbike.com http://sheldonbrown.com
     
  4. Rick Onanian

    Rick Onanian Guest

    On Wed, 03 Sep 2003 22:04:35 -0400, Sheldon Brown <[email protected]> wrote:
    > your knees, it should take a good firm twist on the handlebars to make the stem turn on/in the
    > steerer. If you can't turn the handlebars, it's

    Wouldn't that be a destructive test for a carbon steerer?

    > Sheldon "Tight Enough, But Not Too Tight" Brown
    --
    Rick Onanian
     
  5. Matt

    Matt Guest

    As long as you do not point load the carbon there should be no problem. I always leave at least 1/4"
    of the fork extending beyond the end of the stem. Also, take turns tightening bolts(assuming you
    have more than one) to avoid an uneven distribution of force.

    "Me" <[email protected]> wrote in message news:[email protected]...
    > Hi, when tigtening the bolts that attach a stem on a road carbon steertube (ie not the headset top
    > cap), how tight can I go before damaging the steertube? Or do I even have to worry about causing
    > any damage.
    >
    > On a cromo steertube, I'd say that the stem's bolts would fail or strip
    out
    > long before the steertube, but when I'm tightening a carbon one (heck even when I'm tightening my
    > carbon seatpost) I'm always scared I'll someday
    hear
    > an almighty CRACK!
    >
    > any thoughts?
    >
     
  6. I wrote:

    >> your knees, it should take a good firm twist on the handlebars to make the stem turn on/in the
    >> steerer. If you can't turn the handlebars, it's

    Rick Onanian asked:

    > Wouldn't that be a destructive test for a carbon steerer?

    Only if the stem had been overtightened already, and you were a real gorilla.

    Sheldon "Not _That_ Tight" Brown +---------------------------------------------------+
    | There was a man with a tongue of wood | Who essayed to sing. | And in truth it was
    | lamentable. | But there was one who heard | The clip-clapper of this tongue of wood | And
    | knew what the man wished to sing, | And with that the singer was content. | --Stephen Crane |
    +---------------------------------------------------+ Harris Cyclery, West Newton, Massachusetts
    Phone 617-244-9772 FAX 617-244-1041 http://harriscyclery.com Hard-to-find parts shipped Worldwide
    http://captainbike.com http://sheldonbrown.com
     
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