Carlton Reid on QR safety

Discussion in 'Mountain Bikes' started by James Annan, Feb 4, 2006.

  1. Tim McNamara

    Tim McNamara Guest

    jim beam <[email protected]> writes:

    > Tim McNamara wrote:
    >> Or you could just mount the caliper on the leading side of the fork
    >> and eliminate the need for the discussion entirely.

    >
    > no tim, it's bad deployment of both fork material and caliper
    > material. compressive force [rear mounting] is much safer. which is
    > why it's done.


    We've been through that before, Jim, and it was pointed out to you
    that the loading is the same on either side of the fork. The wheel
    turns in a circle after all.
     


  2. [email protected] wrote:
    > Michael Halliwell writes:
    >
    >
    >>>Anyways, I think that checking the front quick release before each
    >>>ride might be a good idea. In fact, I think I'll go check it right
    >>>now...

    >
    >
    >>You mean, like most manufacturers recommend before each ride in
    >>their owners manuals?

    >
    >
    >>What a novel concept!

    >
    >
    > That is "novel" if you mean that literally, as in "new". In the many
    > years I have ridden bikes with QR hubs, I have not done that and also
    > never found a loose QR when taking a wheel out for, for instance
    > repairing a flat on the road. Maybe the QR's of today are no good and
    > open themselves, as John Howard claimed in his now famous testimony
    > that brought us lawyer lips.
    >
    > This is all so reminiscent of AUDI unwanted acceleration, that was an
    > old story long before because AARP folks driving Cadillacs had a
    > history of stepping on the gas when they meant the brake... so today
    > we must push the brake pedal before engaging the automatic
    > transmission. Not a bad idea, but useless for drivers with good
    > habits.
    >
    > Jobst Brandt


    Funny, in all the time I've been riding with quick releases, it has been
    a recommendation in the owners manual (even with v-brakes / cantilever
    brakes) to check the QR's before each ride.

    Forgive me for stating the obvious, but if something is designed to be
    quickly removable, shouldn't it be checked periodically to ensure that
    when you don't want it to be quickly removed, it won't come out?

    I don't know about you, but I'm going to continute to check my QR's,
    headset and any other component that are vital to my bike's components
    before I ride, just like I do a walk around on the car so I don't drive
    on a flat if some punk slashed my tire.

    Psycho Mike
     
  3. David Damerell wrote:
    > Quoting Tony Raven <[email protected]>:
    > >Try it. Undo your quick release until it just releases over the lawyers
    > >lips and then do it up just enough to marginally retain the axle. Go
    > >test ride the bike carefully. Then tell me that it is not very obvious
    > >that the QR is undone.

    >
    > OK, I will; the local chavs periodically undo front QRs, so - back when I
    > had a front QR hub - I've found myself riding with a loose one once or
    > twice (lucky me, I don't have a disc brake). No, it's not necessarily
    > obvious; and that's on smooth flat pavement, not rattling about like crazy
    > down a hill offroad. The axle is retained in its normal position in the
    > dropouts by the weight of the rider.


    I recall an internet video clip whose link was (IIRC) posted on this
    group. It showed about four mountain bikers starting a ride in a
    parking lot. One guy tried to wheelie over a speed bump (or some such
    thing) and lost his front wheel completely. He apparently hadn't
    fastened his QR at all.

    This shows that, at least for some distances on certain terrains, a
    completely loose QR isn't necessarily obvious. I'd assume that for
    shorter distances in somewhat rougher terrain, a partially loose QR is
    also not obvious.

    This is not a major problem for the rider as long as the force on the
    axle is not toward the dropout opening. But if a disk brake is trying
    to eject the wheel, it's a problem.

    And that's the problem we're discussing. The cam lock QR was never
    intended to provide the primary retention force. Instead, that primary
    retention force was intended to be provided by the direct
    metal-to-metal compressive contact between the dropout metal and the
    top of the axle. IOW, you have the closed end of the dropout slot
    blocking the axle from moving.

    A rear-mounted disk caliper asks the QR to do something it was never
    intended to do.

    - Frank Krygowski
     
  4. Michael Halliwell wrote:
    > [email protected] wrote:
    > >
    > > Anyways, I think that checking the front quick release before each
    > > ride might be a good idea. In fact, I think I'll go check it right
    > > now...
    > >

    >
    > You mean, like most manufacturers recommend before each ride in thier
    > owners manuals?
    >
    > What a novel concept!


    Do you _seriously_ open and shut your front QR before every ride??

    I've been riding bikes with QR wheels since the early 1970s. I never
    check my QR if I'm not in the process of removing or installing the
    wheel, and I've never needed to. On bikes with caliper brakes, they
    simply do not loosen.

    Why? Because there is other metal-to-metal contact resisting any force
    that would try to shift the axle in the dropout. There is no
    possibility of lateral motion within QR adjusting threads. There are
    no influences that would cause loosening.

    For a disk brake bike with rear mount calipers and downward facing
    dropouts, this is not true.

    And by now, we've seen enough reports from mountain bikers who checked
    their QR at the top of a long, rocky descent, found them looser at the
    bottom, and gave us the difference measured in degrees of swing of the
    QR lever. Seems unrealistic to pretend these guys are lying. Why
    would they?

    - Frank Krygowski
     
  5. M-gineering

    M-gineering Guest

    [email protected] wrote:

    >
    > Do you _seriously_ open and shut your front QR before every ride??
    >
    > I've been riding bikes with QR wheels since the early 1970s. I never
    > check my QR if I'm not in the process of removing or installing the
    > wheel, and I've never needed to.


    If you have properly adjusted cup and cone bearings, the bearings will
    develop play with a loose skewer long before the wheels drop out. This
    is very audible if you pick up the bike, provided the bike is well cared
    for and not a ratling heap of misery. But if you don't want to listen.... ;)


    --
    ---
    Marten Gerritsen

    INFOapestaartjeM-GINEERINGpuntNL
    www.m-gineering.nl
     
  6. Ian Blake

    Ian Blake Guest

    On Mon, 06 Feb 2006 21:15:42 -0800, jim beam <[email protected]>
    wrote:


    >>

    >
    >so james, are you able to differentiate between someone that doesn't
    >operate their qr correctly [user error] and design flaw? no? are you
    >going to keep on ignoring the FACT that correctly fastened qr's retain
    >wheels with a significant safety margin? [also ignoring the efficacy of
    >lawyer lips of course.] until you can, you're simply the lunatic the
    >industry is going to ignore.


    I resent the idea that I do not know how to tighten a QR on the front
    wheel of one of my bicycles but a capable of tightening the other
    five.

    My case

    I ride my disc equipped bike for a year with no problem at all. As
    something ages the problems start. I do not suffer ejection despite
    the absence of 'lawyers lips'. However occasionally after sharp
    braking the wheel would move in the drop out causing the disc to rub
    against the brake. So I would need to stop, reset the wheel and
    tighten the QR. I conclude that maybe the problem is with the X-Lite
    QR so I swap in a Shimano one from my bits box. The problem ceases
    for a while but eventually the problem returns.

    Unfortunately I no longer have that fork. When I needed to replace it
    I specified that the brake is mounted on the front of the right hand
    fork. Problem solved.

    Your assertion that the problem does not exist is false. Although
    thankfully like cancer the condition is rare. However you seem to be
    claiming 'None of my friends and family have cancer therefore nobody
    has cancer' I apologise if anyone you know does. It remains correct
    that we find solution to problems even if they do not apply to you.
     
  7. In article <[email protected]>,
    [email protected] says...

    >That is "novel" if you mean that literally, as in "new". In the many
    >years I have ridden bikes with QR hubs, I have not done that and also
    >never found a loose QR when taking a wheel out for, for instance
    >repairing a flat on the road. Maybe the QR's of today are no good and
    >open themselves, as John Howard claimed in his now famous testimony
    >that brought us lawyer lips.


    Me too. I've never had a QR mysteriously loosen itself. I mostly use
    Shimano QR's, but I have used a few of the cheapo units at times. Neither
    had problems when properly used.


    >This is all so reminiscent of AUDI unwanted acceleration, that was an
    >old story long before because AARP folks driving Cadillacs had a
    >history of stepping on the gas when they meant the brake... so today
    >we must push the brake pedal before engaging the automatic
    >transmission. Not a bad idea, but useless for drivers with good
    >habits.


    More importantly those of us with good habits have to pay for what amounts
    to a useless feature.
    -------------
    Alex
     
  8. In article <[email protected]>, [email protected] says...

    >Funny, in all the time I've been riding with quick releases, it has been
    >a recommendation in the owners manual (even with v-brakes / cantilever
    >brakes) to check the QR's before each ride.
    >Forgive me for stating the obvious, but if something is designed to be
    >quickly removable, shouldn't it be checked periodically to ensure that
    >when you don't want it to be quickly removed, it won't come out?


    If it requires more than a quick visual inspection, it is crap.

    >I don't know about you, but I'm going to continute to check my QR's,
    >headset and any other component that are vital to my bike's components
    >before I ride, just like I do a walk around on the car so I don't drive
    >on a flat if some punk slashed my tire.


    If your QR's or headset are coming loose on there own, there is something wrong
    with those parts. You should consider replacing them with something decent
    that works properly.
    ---------------
    Alex
     
  9. In article <[email protected]>,
    [email protected] says...

    >Loosening of the quick release nut from brake forces and
    >rough terrain vibration. The quick release clamp is not
    >designed for these conditions.


    You either have a defective design or improplery tightened QR's. QR's are
    designed to hold your wheel in place under all riding conditions. I ride
    over rough roads, NYC, and I also have a disc brake on the front wheel. I have
    never had my QR come loose. The QR on this bike is one of those cheap made
    in Taiwan jobs that is not as well made as shimano QR's. This leads me to
    believe that your problem may be associated with user error.
    --------------
    Alex
     
  10. Simon Brooke

    Simon Brooke Guest

    in message <[email protected]>, jim beam
    ('[email protected]') wrote:

    >>> Try it. Undo your quick release until it just releases over the
    >>> lawyers lips and then do it up just enough to marginally retain the
    >>> axle. Go test ride the bike carefully. Then tell me that it is not
    >>> very obvious that the QR is undone. I know, I've forgotten to do up
    >>> the QR on occasions when setting off and I have never got more than a
    >>> few yard before it is very obvious something is wrong.

    >>
    >> So what? Even you can't deny that this wheel loss actually happens.

    >
    > i'll deny it for you james. wheel loss CANNOT happen on a fork with
    > lawyer lips. sorry to point out something so fundamentally obvious and
    > painful for you, but reality has to slap you in the face some day.


    It can, and I've seen it. It happened to my next-door neighbour's eleven
    year old son. The bike had V brakes, quick release and lawyer lips - but
    was so badly set up that he /still/ managed to lose the front wheel when
    pulling a wheelie to impress school friends. How he managed to lose a
    front wheel on a fat tyre bike with V brakes amazed me, but he did it.

    Result: broken elbow, broken jaw. He's given up on mountain bikes and now
    rides BMX(!).

    --
    [email protected] (Simon Brooke) http://www.jasmine.org.uk/~simon/

    The trouble with Simon is that he only opens his mouth to change feet.
    ;; of me, by a 'friend'
     
  11. Simon Brooke

    Simon Brooke Guest

    in message <[email protected]>, jim beam
    ('[email protected]') wrote:

    >>
    >> Loosening of the quick release nut from brake forces and
    >> rough terrain vibration. The quick release clamp is not
    >> designed for these conditions.
    >>

    > it's nylocked and serrated, therefore it is designed to resist
    > vibration.


    Uhhhmmm... walk that by me again. Are you saying that all mountain bike
    quick release skewers are nylocked? Or have I misunderstood you?

    --
    [email protected] (Simon Brooke) http://www.jasmine.org.uk/~simon/
    ;; Generally Not Used
    ;; Except by Middle Aged Computer Scientists
     
  12. G.T.

    G.T. Guest

    jim beam wrote:
    > G.T. wrote:
    >
    >> jim beam wrote:
    >>
    >>> [email protected] wrote:
    >>>
    >>>> Benjamin Lewis writes:
    >>>>
    >>>>
    >>>>>>>> I am not questioning the direction of the load, what I _am_
    >>>>>>>> questioning is its magnitude in relation to the other loads
    >>>>>>>> present. To find the value of the ejection force and the value
    >>>>>>>> of the retaining forces we need to know the geometry of the whole
    >>>>>>>> bike and rider.
    >>>>
    >>>>
    >>>>
    >>>>
    >>>>
    >>>>>>> I don't see why. All that is required is what I stated, the ratio
    >>>>>>> of disk diameter to tire OD and the position of the caliper. The
    >>>>>>> fore that the caliper puts on the fork relative to the wheel is as
    >>>>>>> I stated, only caliper location is the matter at hand.
    >>>>
    >>>>
    >>>>
    >>>>
    >>>>
    >>>>>> Except that there is a maximum force that be generated in this way,
    >>>>>> and to find the maximum we need to consider the factors I've
    >>>>>> mentioned.
    >>>>
    >>>>
    >>>>
    >>>>
    >>>>
    >>>>>> Assuming a conventional upright bike, with wheelbase a little over
    >>>>>> 1 metre, the maximum braking effort is found when the back wheel
    >>>>>> lifts, at which point the retardation will be about 0.65g.
    >>>>
    >>>>
    >>>>
    >>>>
    >>>>
    >>>>> You don't think you can momentarily spike the braking force above
    >>>>> that without doing an endo?
    >>>>
    >>>>
    >>>>
    >>>>
    >>>>
    >>>> Use your imagination. The rider is descending a bumpy trail, causing
    >>>> intermittent lift-off. When he lands, the wheel skids and he bounces
    >>>> again. Anyone who has some trail experience has heard and seen this
    >>>> effect. It does not involve and end-over.
    >>>
    >>>
    >>>
    >>>
    >>> so jobst, on my ride this sunday, i descended three sections of rocky
    >>> trail that were so steep,

    >>
    >>
    >>
    >> Get back to us when you descend something for more than 30 seconds.
    >>
    >> Greg
    >>

    > eh? how does that effect grade or braking magnitude???


    Uhh, to loosen the QR you need to be braking a lot more than can be done
    on those wimpy Marin hills.

    Greg

    --
    "All my time I spent in heaven
    Revelries of dance and wine
    Waking to the sound of laughter
    Up I'd rise and kiss the sky" - The Mekons
     
  13. Simon Brooke

    Simon Brooke Guest

    in message <[email protected]>, Tim McNamara
    ('[email protected]') wrote:

    > jim beam <[email protected]> writes:
    >
    >> Tim McNamara wrote:
    >>> Or you could just mount the caliper on the leading side of the fork
    >>> and eliminate the need for the discussion entirely.

    >>
    >> no tim, it's bad deployment of both fork material and caliper
    >> material. compressive force [rear mounting] is much safer. which is
    >> why it's done.

    >
    > We've been through that before, Jim, and it was pointed out to you
    > that the loading is the same on either side of the fork. The wheel
    > turns in a circle after all.


    OK, I'm not persuaded by that. Suppose with a conventional design the
    bolts or other hardware holding the calliper to the fork fail, you still
    stop, and probably still stop moderately under control, because the
    braking forces will hold the calliper in place at least until the brake
    is released. If the calliper is in front of the fork, though, failure of
    the mounting hardware would cause the calliper to rotate with the wheel
    until either it came up short on the end of the hose or impacted with
    the back of the fork suddenly at the end of a complete rotation, and I
    don't think either of those outcomes is conducive of safe stopping.

    However, you have to weigh that risk against the ejection risk, and
    frankly the sudden and total failure of the calliper mounting hardware
    is not particularly likely.

    --
    [email protected] (Simon Brooke) http://www.jasmine.org.uk/~simon/
    ; gif ye hes forget our auld plane Scottis quhilk your mother lerit you,
    ; in tymes cuming I sall wryte to you my mind in Latin, for I am nocht
    ; acquyntit with your Southeron
    ;; Letter frae Ninian Winyet tae John Knox datit 27t October 1563
     
  14. > I ride over rough roads, NYC

    s/rough/"rough" ?
     
  15. Jay Beattie

    Jay Beattie Guest

    "M-gineering" <[email protected]> wrote in message
    news:[email protected]
    > [email protected] wrote:
    >
    > >
    > > Do you _seriously_ open and shut your front QR before every

    ride??
    > >
    > > I've been riding bikes with QR wheels since the early 1970s.

    I never
    > > check my QR if I'm not in the process of removing or

    installing the
    > > wheel, and I've never needed to.

    >
    > If you have properly adjusted cup and cone bearings, the

    bearings will
    > develop play with a loose skewer long before the wheels drop

    out. This
    > is very audible if you pick up the bike, provided the bike is

    well cared
    > for and not a ratling heap of misery. But if you don't want to

    listen.... ;)

    If a disc brake wheel is askew in the front drop outs due to a
    loose QR, you will also get noticeable disc rubbing. So the
    wheel ejection scenario has to develop pretty damn fast -- from
    no rubbing to out of the lawyers lips in one fell swoop. Not
    saying that it could not happen on a MTB with a big hit on a rock
    or stump, but on a road bike, it seems remote (of course, I say
    this because I ride a cross bike with discs and want to feel
    safe). -- Jay Beattie.
     
  16. Simon Brooke wrote:

    > in message <[email protected]>, Tim McNamara
    > ('[email protected]') wrote:
    >
    >> jim beam <[email protected]> writes:
    >>
    >>> Tim McNamara wrote:
    >>>> Or you could just mount the caliper on the leading side of the fork
    >>>> and eliminate the need for the discussion entirely.
    >>>
    >>> no tim, it's bad deployment of both fork material and caliper
    >>> material. compressive force [rear mounting] is much safer. which is
    >>> why it's done.

    >>
    >> We've been through that before, Jim, and it was pointed out to you
    >> that the loading is the same on either side of the fork. The wheel
    >> turns in a circle after all.

    >
    > OK, I'm not persuaded by that. Suppose with a conventional design the
    > bolts or other hardware holding the calliper to the fork fail, you still
    > stop, and probably still stop moderately under control, because the
    > braking forces will hold the calliper in place at least until the brake
    > is released. If the calliper is in front of the fork, though, failure of
    > the mounting hardware would cause the calliper to rotate with the wheel
    > until either it came up short on the end of the hose or impacted with
    > the back of the fork suddenly at the end of a complete rotation, and I
    > don't think either of those outcomes is conducive of safe stopping.
    >
    > However, you have to weigh that risk against the ejection risk, and
    > frankly the sudden and total failure of the calliper mounting hardware
    > is not particularly likely.


    And it's easy to design the bolts and other hardware such that they see no
    more stress than do conventional cantilever bosses, the safety of which
    nobody seems to have a problem with.

    Apparently the extra few grams such a design would incur is too much for
    all those weight weenies on their disk brake equipped mountain bikes...

    --
    Benjamin Lewis

    Now is the time for all good men to come to.
    -- Walt Kelly
     
  17. James Annan

    James Annan Guest

    [email protected] wrote:

    > David Damerell wrote:
    >
    >>Quoting Tony Raven <[email protected]>:
    >>
    >>>Try it. Undo your quick release until it just releases over the lawyers
    >>>lips and then do it up just enough to marginally retain the axle. Go
    >>>test ride the bike carefully. Then tell me that it is not very obvious
    >>>that the QR is undone.

    >>
    >>OK, I will; the local chavs periodically undo front QRs, so - back when I
    >>had a front QR hub - I've found myself riding with a loose one once or
    >>twice (lucky me, I don't have a disc brake). No, it's not necessarily
    >>obvious; and that's on smooth flat pavement, not rattling about like crazy
    >>down a hill offroad. The axle is retained in its normal position in the
    >>dropouts by the weight of the rider.

    >
    >
    > I recall an internet video clip whose link was (IIRC) posted on this
    > group. It showed about four mountain bikers starting a ride in a
    > parking lot. One guy tried to wheelie over a speed bump (or some such
    > thing) and lost his front wheel completely. He apparently hadn't
    > fastened his QR at all.
    >
    > This shows that, at least for some distances on certain terrains, a
    > completely loose QR isn't necessarily obvious. I'd assume that for
    > shorter distances in somewhat rougher terrain, a partially loose QR is
    > also not obvious.


    IIRC this was at the end of a ride, the QR had actually broken at some
    unknown point during the ride. Given the way that disk brake users often
    describe routinely overtightening their skewers to keep the wheel in
    place, it's hardly surprising that such failures happen. But anyway,
    your point still stands.


    James
    --
    James Annan
    see web pages for email
    http://www.ne.jp/asahi/julesandjames/home/
    http://julesandjames.blogspot.com/
     
  18. James Annan

    James Annan Guest

    Ian Blake wrote:

    > On Mon, 06 Feb 2006 21:15:42 -0800, jim beam <[email protected]>
    > wrote:
    >
    >
    >
    >>so james, are you able to differentiate between someone that doesn't
    >>operate their qr correctly [user error] and design flaw? no? are you
    >>going to keep on ignoring the FACT that correctly fastened qr's retain
    >>wheels with a significant safety margin? [also ignoring the efficacy of
    >>lawyer lips of course.] until you can, you're simply the lunatic the
    >>industry is going to ignore.

    >
    >
    > I resent the idea that I do not know how to tighten a QR on the front
    > wheel of one of my bicycles but a capable of tightening the other
    > five.
    >
    > My case
    >
    > I ride my disc equipped bike for a year with no problem at all. As
    > something ages the problems start. I do not suffer ejection despite
    > the absence of 'lawyers lips'. However occasionally after sharp
    > braking the wheel would move in the drop out causing the disc to rub
    > against the brake. So I would need to stop, reset the wheel and
    > tighten the QR. I conclude that maybe the problem is with the X-Lite
    > QR so I swap in a Shimano one from my bits box. The problem ceases
    > for a while but eventually the problem returns.
    >
    > Unfortunately I no longer have that fork. When I needed to replace it
    > I specified that the brake is mounted on the front of the right hand
    > fork. Problem solved.


    Obviously, either
    a) you are a clueless numpty who doesn't know how to operate a QR
    b) you don't exist
    otherwise you wouldn't have this problem, since there is no problem.

    See, that was easy...

    Since no-one who both exists, and is not clueless, has reported any
    problem, there is no problem.

    Case closed!

    James
    --
    James Annan
    see web pages for email
    http://www.ne.jp/asahi/julesandjames/home/
    http://julesandjames.blogspot.com/
     
  19. Clive George

    Clive George Guest

Loading...
Loading...