Over tightening a seat collar QR

Discussion in 'Cycling Equipment' started by Paul, Jun 7, 2003.

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  1. Paul

    Paul Guest

    During my last bike service the original bolted seatpost collar was found to be cracked so it was
    replaced. Recently I noticed that over time my seat was gradually sinking and since then I have
    managed to round of the allen bolt trying to tighen things up so I have replaced it with a quick
    release skewer. I marked a line where the post should be and again noticed a slight sinking of the
    post, although not much - 2 or 3mm over a 40 mile ride. I usually tighten a bolt/QR in a seat collar
    to the point where I can no longer twist the post/sadde.

    Obviously I tightened things up a bit but am concerned about over tighening (more for the sake of
    the frame than anything else. A couple of full turns of the QR handle and it's so tight that the
    post is tight in the fame with the QR open - obviously too tight so I've settled for just tightening
    it up a bit more than how it was set in the bike shop (the post drops as soon as the QR is opened
    and the QR starts to pinch at the half way closed point and so far no more sinking).

    If there are any more sinking problems I'll just twist the QR thumb nut a fraction but, as I have
    said, I am concerned about over tightening. Would it be possible to over tighten the QR and damage
    the fame (7005 T6 ally) and are there any signs of over tightening I should be looking for?

    The post is alloy and shimmed into the seat tube and is well greased (could this be a problem?) The
    QR collar is by Outland. I have a fairly upright position so a fair bit of my weight is supported by
    the saddle.

    Thanks for any thoughts,

    Paul.
     
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  2. A Muzi

    A Muzi Guest

    "Paul" <[email protected]> wrote in message news:[email protected]...
    > During my last bike service the original bolted seatpost collar was found
    to
    > be cracked so it was replaced. Recently I noticed that over time my seat
    was
    > gradually sinking and since then I have managed to round of the allen bolt trying to tighen things
    > up so I have replaced it with a quick release skewer. I marked a line where the post should be and
    > again noticed a
    slight
    > sinking of the post, although not much - 2 or 3mm over a 40 mile ride. I usually tighten a bolt/QR
    > in a seat collar to the point where I can no longer twist the post/sadde.
    >
    > Obviously I tightened things up a bit but am concerned about over
    tighening
    > (more for the sake of the frame than anything else. A couple of full turns of the QR handle and
    > it's so tight that the post is tight in the fame with the QR open - obviously too tight so I've
    > settled for just tightening it
    up
    > a bit more than how it was set in the bike shop (the post drops as soon as the QR is opened and
    > the QR starts to pinch at the half way closed point
    and
    > so far no more sinking).
    >
    > If there are any more sinking problems I'll just twist the QR thumb nut a fraction but, as I have
    > said, I am concerned about over tightening. Would
    it
    > be possible to over tighten the QR and damage the fame (7005 T6 ally) and are there any signs of
    > over tightening I should be looking for?
    >
    > The post is alloy and shimmed into the seat tube and is well greased
    (could
    > this be a problem?) The QR collar is by Outland. I have a fairly upright position so a fair bit of
    > my weight is supported by the saddle.

    Check these things:

    Slip the setapost all the way into the seat tube. Wiggle it. There should be barely perceptible
    play if any.

    See if the next size larger will fit. ( They come in two-tenths increments except for 30.9).The next
    size larger should not go easily all the way into an MTB frame and should not go all the way in at
    all in a road bike. (MTB designers assume you will change the height more frequently and generally
    use a looser fit standard)

    Now lubricate the cam of your seat Q/R and the threads of the nut. Close it with normal pressure (
    no purple mark on your hand). Ensure there is still a visible gap between the sides of the seat
    collar and also a gap in the frame's slit itself. If the sides touch, you either have a too-small
    seatpost, the wrong sleeve or you need to slit the collar or frame larger.

    Lastly, you are correct to lubricate the sleeve and post. With proper fit that lubricant will keep
    water out and reduce corrosion but should not prevent secure positioning of the post.
    --
    Andrew Muzi http://www.yellowjersey.org Open every day since 1 April 1971
     
  3. Paul

    Paul Guest

    Thanks for the tips.

    There is no significant play and I've had it looked at by the guy at my LBS who says it's the right
    size. I currently have about 4-5 mm of a gap between the edges of the slit in the seat tube, is this
    safe to assume it is not over tightened?

    I may change the seatpost anyway at a later date for one that isn't shimmed.

    Thanks again for taking the time to reply.

    Kind Regards, Paul.
     
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