Poll Disc/QR: Dropout marks?

Discussion in 'Cycling Equipment' started by D Heath, May 17, 2003.

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  1. D Heath

    D Heath Guest

    To follow up on Mark Hickey's question in the Disc/QR thread, I'm starting this thread to have a
    separate thread just for riders to give observations about any kinds of evidence that can be seen on
    the dropouts of forks used with front disc brakes. It seems to me it would be helpful to note
    approximately how many miles the fork has been used with discs, just for benefit of those reading to
    evaluate your observations. As far as I am concerned, I am open-minded about this problem. It seems
    clear that a change in design is highly likely and probably rightly so. On the other hand, I'll
    continue to ride with discs (I personally never intend to go back to previous brake designs on my
    MTB) and will take the best precautions I can to see that the QR engagement is tight and secure. I
    looked at my fork to see if I see signs of QR "wandering" on the dropout faces. I see no evidence on
    the Marzocchi currently installed. All indentations from the QR are very sharp and precise, with no
    sign of "wandering" or moving at all. That fork only has about 300 miles on it, however, so I looked
    at the SID fork that had been on the bike several years, with the last 2000+ miles using Hayes disc
    brakes and 6" rotors. The miles are almost all singletrack on very mountainous terrain, with plenty
    of long (3-4 mile) downhills. I am not sure what to make of the SID dropouts. The marks on the
    inside of the dropouts are as crisp and sharp as those on all surfaces of the Marzocchi dropouts.
    However, the outer sides of the dropouts are less distinct. I don't see any signs of the QR sliding
    up and down, but the little indentations are not as clear. This actually might be related to my roof
    rack fork mount attachment points. I use a Yakima Steelhead fork mount, which I think does not have
    quite as sharply defined indention ridges(?) as most QRs I have used. It might be that it has
    smoothed out the dropout faces on the SID over time, and since the Marzocchi has not been used as
    much, maybe it just has not had time to show this pattern. On the other hand, maybe the SID is
    showing signs of movement of the QR. Since the QR nut cannot really move far even if it were loose,
    we may not be able to tell much from this anyway?? Both the SID and the Marzocchi "lawyer lips"
    contain the QR nuts so well that it cannot do much sliding around even when loose. I do not recall
    ever having had a loose QR on the trail since using disc brakes. As for QR tightening issues, I use
    a fork mount rack on the vehicle, so I have to put the front tire on fresh before every ride. (Kinda
    glad about that, in light of recent events!) I also tend to tighten the QR pretty firmly as a matter
    of practice, though I might be tightening it a bit stronger these days.

    --
    Off to ride the mountains, Dale Heath To reply, poke out my eye.
     
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  2. Headshok Fatty Ultra Crossmax Disc 2000 &2002 - standard mavic skewers magura marta discs,
    previously modified coda expert discs no sign of movement whatsoever

    the rear definitely moves however as the tolerance of frame to hub is not as tight radially as the
    front end - never worried me in terms of safety though

    "D Heath" <[email protected]> wrote in message
    news:[email protected]... To follow up on Mark Hickey's question in the
    Disc/QR thread, I'm starting this thread to have a separate thread just for riders to give
    observations about any kinds of evidence that can be seen on the dropouts of forks used with front
    disc brakes. It seems to me it would be helpful to note approximately how many miles the fork has
    been used with discs, just for benefit of those reading to evaluate your observations. As far as I
    am concerned, I am open-minded about this problem. It seems clear that a change in design is highly
    likely and probably rightly so. On the other hand, I'll continue to ride with discs (I personally
    never intend to go back to previous brake designs on my MTB) and will take the best precautions I
    can to see that the QR engagement is tight and secure. I looked at my fork to see if I see signs of
    QR "wandering" on the dropout faces. I see no evidence on the Marzocchi currently installed. All
    indentations from the QR are very sharp and precise, with no sign of "wandering" or moving at all.
    That fork only has about 300 miles on it, however, so I looked at the SID fork that had been on the
    bike several years, with the last 2000+ miles using Hayes disc brakes and 6" rotors. The miles are
    almost all singletrack on very mountainous terrain, with plenty of long (3-4 mile) downhills. I am
    not sure what to make of the SID dropouts. The marks on the inside of the dropouts are as crisp and
    sharp as those on all surfaces of the Marzocchi dropouts. However, the outer sides of the dropouts
    are less distinct. I don't see any signs of the QR sliding up and down, but the little indentations
    are not as clear. This actually might be related to my roof rack fork mount attachment points. I use
    a Yakima Steelhead fork mount, which I think does not have quite as sharply defined indention
    ridges(?) as most QRs I have used. It might be that it has smoothed out the dropout faces on the SID
    over time, and since the Marzocchi has not been used as much, maybe it just has not had time to show
    this pattern. On the other hand, maybe the SID is showing signs of movement of the QR. Since the QR
    nut cannot really move far even if it were loose, we may not be able to tell much from this anyway??
    Both the SID and the Marzocchi "lawyer lips" contain the QR nuts so well that it cannot do much
    sliding around even when loose. I do not recall ever having had a loose QR on the trail since using
    disc brakes. As for QR tightening issues, I use a fork mount rack on the vehicle, so I have to put
    the front tire on fresh before every ride. (Kinda glad about that, in light of recent events!) I
    also tend to tighten the QR pretty firmly as a matter of practice, though I might be tightening it a
    bit stronger these days.

    --
    Off to ride the mountains, Dale Heath To reply, poke out my eye.
     
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