The theory gains momentum...

Discussion in 'Mountain Bikes' started by Bomba, May 15, 2003.

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  1. Nelson Binch

    Nelson Binch Guest

    "bomba" <[email protected]> wrote in message news:[email protected]...
    | http://www.singletrackworld.co.uk/article.php?sid=1005
    |

    Reading the entire article actually reinforces my belief that these unfortunate incidents were
    either poorly applied quick releases or a mechanical fault (not a design issue) with part of the
    equipment.

    ---
    __o _`\(,_ Cycling is life, (_)/ (_) all the rest, just details. Nelson Binch =^o.o^=
    http://intergalax.com

    Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.481 / Virus Database: 277 -
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  2. B. Sanders

    B. Sanders Guest

    "Nelson Binch" <[email protected]> wrote in message
    news:[email protected]...
    > "bomba" <[email protected]> wrote in message news:[email protected]...
    > | http://www.singletrackworld.co.uk/article.php?sid=1005
    > |
    >
    > Reading the entire article actually reinforces my belief that these unfortunate incidents were
    > either poorly applied quick releases or a mechanical fault (not a design issue) with part of the
    > equipment.

    I agree; but I also think that Jim Annan's calculations point to the increased importance of *tight*
    QR's when using discs. With V-brakes or canti's, all you have to do is make sure the wheel doesn't
    fall out of the dropouts. With discs, you have significant force exerted to try and pull the wheels
    out of the dropouts. That's very different.

    Hey, Nelson, you have quite a nice fleet of bikes. I hadn't had a look at your website before. Your
    Giant Prodigy looks like exactly the sort of bike that is missing from my fleet. The local police
    bike auction is in 2 days - maybe I can scoop up one like it for a song (though perhaps not with the
    Melted Meteor paintjob :)

    When are you gonna add a recumbent to that fleet? Go test ride a RANS Rocket and tell me it doesn't
    put a big smile on your face.

    Cheers,

    Barry
     
  3. Nelson Binch

    Nelson Binch Guest

    "B. Sanders" <[email protected]> wrote in message
    news:[email protected]...
    | "Nelson Binch" <[email protected]> wrote in message
    | news:[email protected]...
    | > "bomba" <[email protected]> wrote in message news:[email protected]...
    | > | http://www.singletrackworld.co.uk/article.php?sid=1005
    | > |
    | >
    | > Reading the entire article actually reinforces my belief that these unfortunate incidents were
    | > either poorly applied quick releases or a mechanical fault (not a design issue) with part of the
    | > equipment.
    |
    | I agree; but I also think that Jim Annan's calculations point to the increased importance of
    | *tight* QR's when using discs. With V-brakes or canti's, all you have to do is make sure the wheel
    | doesn't fall out of the dropouts. With discs, you have significant force exerted to try and pull
    the
    | wheels out of the dropouts. That's very different.

    IMHO, it may be from using "Designer" skewers. None of them tighten quite as well as the original
    "Campy" style like Shimano uses.

    | Hey, Nelson, you have quite a nice fleet of bikes. I hadn't had a look at your website before.
    | Your Giant Prodigy looks like exactly the sort of
    bike
    | that is missing from my fleet. The local police bike auction is in 2
    days -
    | maybe I can scoop up one like it for a song (though perhaps not with the Melted Meteor
    | paintjob :)
    |
    | When are you gonna add a recumbent to that fleet? Go test ride a RANS Rocket and tell me it
    | doesn't put a big smile on your face.

    I'd dearly love to have one, but I want a more traditionally styled one (under the seat steering)
    but they're way too expensive for me at the moment.

    ---
    __o _`\(,_ Cycling is life, (_)/ (_) all the rest, just details. Nelson Binch =^o.o^=
    http://intergalax.com

    Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.481 / Virus Database: 277 -
    Release Date: 5/13/2003
     
  4. Amerigo

    Amerigo Guest

    "bomba" <[email protected]> ha scritto nel messaggio
    news:[email protected]...
    > http://www.singletrackworld.co.uk/article.php?sid=1005
    >

    I think that the danger is much bigger for the front brake, because the position of the rear brake
    is different, so the force generated by the brake is not directed vertically,but it is - almost -
    horizontal, how much horizontal it is, it depends from the position of the brake: if it is
    vertically above the hub, the force will be horizontal, if it is not, the resultant force will try
    to move down the hub

    http://www.rothar.com/160303.htm

    From: James Subject: Disc brakes and QRs Yes, and I'm in the same position as you. I don't think
    it's a big safety issue, but in my case it is a slightly annoying one. It depends on how the
    dropouts are angled relative to the disk calliper, and my bike (Ventana El Conquistador tandem) is
    particularly bad, with rearward facing dropouts which are at exactly the worst possible angle for
    the disc brake. The maker soon realised the error and changed to more conventional vertical ones. If
    only major fork manufacturers were so responsive.... That is another reason why I am particularly
    aware of the disk brake issue - our rear wheel occasionally slips a bit although now I do the QR up
    bloody tight and it's been ok for some time. It's similar to QRs with horizontal dropouts for
    singlespeeding - you can just about get away with it, but slippage is a headache (rear wheel slip
    while honking up a big hill is not a matter of life and death though). I wouldn't trust my life to
    the rear wheel not slipping, but its not a big safety issue in my view since even if the rear wheel
    slips sideways a bit or pulls out completely, this is only going to cause a skid and not a headfirst
    plummet to the ground (especially on a tandem with the long stable wheelbase). I don't think
    different disk calliper types will make a significant difference, it's really just a matter of
    geometry. The open fork ends should point directly away from the calliper itself, rather than being
    nearly parallel to the tangent.
     
  5. Dave Stocker

    Dave Stocker Guest

    So this guy Chris Juden says that it does not seem to happen with Shimano QRs begause of their
    gripping surface. I wonder if this really is the case.

    Have these incidents only happened to people with Chi-Chi hubs?

    Is this based on any kind of statistical analysis of "QR not fastened correctly" accidents or just a
    "they look like they should grip pretty good" hypothesis?

    I am ok there, only Shimano (Deore and XT) stuff. WAIT! The front hub of the bike with discs has a
    Specialized Strongarm. Not exactly Chi-Chi, but I think I want to go have a look at the QR.

    -Dave, on the way to the garage...
     
  6. Dave Stocker

    Dave Stocker Guest

    "amerigo" <[email protected]> schrieb im Newsbeitrag
    news:[email protected]...
    >
    > From: James Subject: Disc brakes and QRs Yes, and I'm in the same position as you. I don't think
    > it's a big safety
    ...
    > significant difference, it's really just a matter of geometry. The open
    fork
    > ends should point directly away from the calliper itself, rather than
    being
    > nearly parallel to the tangent.
    >
    IMHO it would be best if they were angled foreward about 30 degrees or so, but this may comprimise
    the strength of the dropout.

    -Dave
     
  7. In article <[email protected]>, [email protected] says...
    > So this guy Chris Juden says that it does not seem to happen with Shimano QRs begause of their
    > gripping surface. I wonder if this really is the case.
    >
    > Have these incidents only happened to people with Chi-Chi hubs?
    >
    > Is this based on any kind of statistical analysis of "QR not fastened correctly" accidents or just
    > a "they look like they should grip pretty good" hypothesis?
    >
    > I am ok there, only Shimano (Deore and XT) stuff. WAIT! The front hub of the bike with discs has a
    > Specialized Strongarm. Not exactly Chi-Chi, but I think I want to go have a look at the QR.
    >
    > -Dave, on the way to the garage...
    >
    >
    >
    >

    I've never seen this happen period, what exactly happened to the guy that crashed, did the shaft of
    the QR snap or did it just slip out of the drop out? Specialized/Formula stout hubs have an
    oversized QR shaft which makes it stiffer, too bad Specialized usually puts a radially spoked wheel
    together with it for maximum noodle effect.
    --
    _________________________
    Chris Phillipo - Cape Breton, Nova Scotia http://www.ramsays-online.com
     
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