Circus acts

Discussion in 'Cycling Equipment' started by Epicyclist, Jun 2, 2003.

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  1. Epicyclist

    Epicyclist Guest

    As I watch my little boy fight his bicycle and fall off in his transition from stabilisers to free
    cycling I think "Gyroscopes". Yet many still say that balancing on a bike is a circus act of
    steering correction. I can see that this effect becomes significant below 2mph just before you fall
    off due to lack of forward velocity but why does the myth still prevail?
     
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  2. Peter

    Peter Guest

    epicyclist wrote:
    > As I watch my little boy fight his bicycle and fall off in his transition from stabilisers to free
    > cycling I think "Gyroscopes". Yet many still say that balancing on a bike is a circus act of
    > steering correction. I can see that this effect becomes significant below 2mph just before you
    > fall off due to lack of forward velocity but why does the myth still prevail?

    Possibly because experiments have been done with counter-rotating wheels mounted on the bicycle to
    cancel gyroscopic effects. The bike still rides and steers about the same although I believe it did
    fall over faster when it was pushed and let go without a rider. Various modifications of the
    steering geometry were also tried and described in an article in "Physics Today" in early 1967.
     
  3. Epicyclist

    Epicyclist Guest

    Peter wrote:
    > epicyclist wrote:
    >
    >> As I watch my little boy fight his bicycle and fall off in his transition from stabilisers to
    >> free cycling I think "Gyroscopes". Yet many still say that balancing on a bike is a circus act of
    >> steering correction. I can see that this effect becomes significant below 2mph just before you
    >> fall off due to lack of forward velocity but why does the myth still prevail?
    >
    >
    > Possibly because experiments have been done with counter-rotating wheels mounted on the bicycle to
    > cancel gyroscopic effects. The bike still rides and steers about the same although I believe it
    > did fall over faster when it was pushed and let go without a rider. Various modifications of the
    > steering geometry were also tried and described in an article in "Physics Today" in early 1967.
    >
    >
    Yes, they would not have made the grade for GCSE though would they?
     
  4. Peter

    Peter Guest

    epicyclist wrote:
    > Peter wrote:
    >
    >> epicyclist wrote:
    >>
    >>> As I watch my little boy fight his bicycle and fall off in his transition from stabilisers to
    >>> free cycling I think "Gyroscopes". Yet many still say that balancing on a bike is a circus act
    >>> of steering correction. I can see that this effect becomes significant below 2mph just before
    >>> you fall off due to lack of forward velocity but why does the myth still prevail?
    >>
    >>
    >>
    >> Possibly because experiments have been done with counter-rotating wheels mounted on the
    >> bicycle to cancel gyroscopic effects. The bike still rides and steers about the same although
    >> I believe it did fall over faster when it was pushed and let go without a rider. Various
    >> modifications of the steering geometry were also tried and described in an article in "Physics
    >> Today" [wrong date].
    >>
    >>
    > Yes, they would not have made the grade for GCSE though would they?

    I suggest you read the article - the correct reference is David Jones, "Physics Today," April,
    1970, pp34-40. The conclusion is that the bicycle has substantial inherent stability due to the
    steering geometry
    - so it is neither the result of gyroscopic forces nor a circus balancing act.

    BTW, if you let your son learn to first balance his bicycle by lowering the seat, removing the
    pedals and having him push it along 'hobby horse' style he can quickly learn to ride without any
    falls. Once he can push off and coast for fairly long distances without touching his feet to the
    ground you can reinstall the pedals and gradually raise the seat. Typically takes just a couple
    hours and results in no skinned knees. {Of course those will likely come later anyway when he
    practices jumping over bumps and taking corners too fast.)
     
  5. On Mon, 02 Jun 2003 09:13:26 +0100, epicyclist <[email protected]> wrote:

    >As I watch my little boy fight his bicycle and fall off in his transition from stabilisers to free
    >cycling I think "Gyroscopes". Yet many still say that balancing on a bike is a circus act of
    >steering correction. I can see that this effect becomes significant below 2mph just before you fall
    >off due to lack of forward velocity but why does the myth still prevail?

    How does a trackstanding rider stay up if the bike's wheels aren't moving?

    Barry
     
  6. Kit Wolf

    Kit Wolf Guest

    On Mon, 02 Jun 2003 15:05:49 +0000, Peter wrote:

    > epicyclist wrote:
    >> As I watch my little boy fight his bicycle and fall off in his transition from stabilisers to
    >> free cycling I think "Gyroscopes". Yet many still say that balancing on a bike is a circus act of
    >> steering correction. I can see that this effect becomes significant below 2mph just before you
    >> fall off due to lack of forward velocity but why does the myth still prevail?
    >
    > Possibly because experiments have been done with counter-rotating wheels mounted on the bicycle to
    > cancel gyroscopic effects. The bike still rides and steers about the same although I believe it
    > did fall over faster when it was pushed and let go without a rider. Various modifications of the
    > steering geometry were also tried and described in an article in "Physics Today" in early 1967.

    My physicist flatmate swears he saw an educational video where a cyclist rode a bike with a fixed
    speed flywheel attached. When he accelerated to the correct speed, the flywheel and bicycle wheel
    gyroscopic forces exactly counteracted each other and he fell off.

    I'm a sceptic, as I don't see why the amount of trail should have any effect on the magnitude of the
    gyroscopic forces, though it certainly affects the ridability of the bike..?

    KW
     
  7. Mark Janeba

    Mark Janeba Guest

    Peter wrote:
    > BTW, if you let your son learn to first balance his bicycle by lowering the seat, removing the
    > pedals and having him push it along 'hobby horse' style he can quickly learn to ride without any
    > falls. Once he can push off and coast for fairly long distances without touching his feet to the
    > ground you can reinstall the pedals and gradually raise the seat. Typically takes just a couple
    > hours and results in no skinned knees. {Of course those will likely come later anyway when he
    > practices jumping over bumps and taking corners too fast.)

    Good advice - here's another useful tip (worked for my kids):

    Find a *gentle* grassy slope, likely in a park. In combination with the advice above, allow child to
    coast down the slope. "Grassy" to keep speed down and make falls inconsequential. "gentle" also to
    keep speed down.

    Regards,
    --
    Mark Janeba remove antispam phrase in address to reply
     
  8. Epicyclist

    Epicyclist Guest

    B a r r y B u r k e J r . wrote:
    > On Mon, 02 Jun 2003 09:13:26 +0100, epicyclist <[email protected]> wrote:
    >
    >
    >>As I watch my little boy fight his bicycle and fall off in his transition from stabilisers to free
    >>cycling I think "Gyroscopes". Yet many still say that balancing on a bike is a circus act of
    >>steering correction. I can see that this effect becomes significant below 2mph just before you
    >>fall off due to lack of forward velocity but why does the myth still prevail?
    >
    >
    > How does a trackstanding rider stay up if the bike's wheels aren't moving?
    >
    > Barry
    The same way I do when I stop dead at traffic lights, with a bit of help from the fixed wheel. It's
    definitely not related to the way the bike stays up whilst moving.
     
  9. Peter

    Peter Guest

    Kit Wolf wrote:
    > On Mon, 02 Jun 2003 15:05:49 +0000, Peter wrote:
    >
    >
    >>epicyclist wrote:
    >>
    >>>As I watch my little boy fight his bicycle and fall off in his transition from stabilisers to
    >>>free cycling I think "Gyroscopes". Yet many still say that balancing on a bike is a circus act of
    >>>steering correction. I can see that this effect becomes significant below 2mph just before you
    >>>fall off due to lack of forward velocity but why does the myth still prevail?
    >>
    >>Possibly because experiments have been done with counter-rotating wheels mounted on the bicycle to
    >>cancel gyroscopic effects. The bike still rides and steers about the same although I believe it
    >>did fall over faster when it was pushed and let go without a rider. Various modifications of the
    >>steering geometry were also tried and described in an article in "Physics Today" in early 1967.
    >
    >
    > My physicist flatmate swears he saw an educational video where a cyclist rode a bike with a fixed
    > speed flywheel attached. When he accelerated to the correct speed, the flywheel and bicycle wheel
    > gyroscopic forces exactly counteracted each other and he fell off.
    >
    > I'm a sceptic, as I don't see why the amount of trail should have any effect on the magnitude of
    > the gyroscopic forces, though it certainly affects the ridability of the bike..?

    He should have easy access to back issues of "Physics Today," so have him look up the April, 1970
    issue. It discusses the effects of trail and experimental results of building bikes with differing
    amounts of positive and negative trail.

    Jones also built a bike with a counter-rotating wheel next to the front wheel which cancels
    the gyroscopic effects but did not make the bicycle hard to ride, so I have doubts about the
    above video.
     
  10. Epicyclist

    Epicyclist Guest

    Peter wrote:
    > epicyclist wrote:
    >
    >> Peter wrote:
    >>
    >>> epicyclist wrote:
    >>>
    >>>> As I watch my little boy fight his bicycle and fall off in his transition from stabilisers to
    >>>> free cycling I think "Gyroscopes". Yet many still say that balancing on a bike is a circus act
    >>>> of steering correction. I can see that this effect becomes significant below 2mph just before
    >>>> you fall off due to lack of forward velocity but why does the myth still prevail?
    >>>
    >>>
    >>>
    >>>
    >>> Possibly because experiments have been done with counter-rotating wheels mounted on the bicycle
    >>> to cancel gyroscopic effects. The bike still rides and steers about the same although I believe
    >>> it did fall over faster when it was pushed and let go without a rider. Various modifications of
    >>> the steering geometry were also tried and described in an article in "Physics Today" [wrong
    >>> date].
    >>>
    >>>
    >> Yes, they would not have made the grade for GCSE though would they?
    >
    >
    > I suggest you read the article - the correct reference is David Jones, "Physics Today," April,
    > 1970, pp34-40. The conclusion is that the bicycle has substantial inherent stability due to the
    > steering geometry
    > - so it is neither the result of gyroscopic forces nor a circus balancing act.
    Thankyou, as I remember it a lovely example of an uncontrolled experiment, hence my
    comments about making the grade.

    The steering geometry provides stability, so that the active forces (gyroscopic) that come
    into play when the bike deviates from the upright straight line will act to correct the
    situation. Unless of course the rider is not at one with the machine and tries to override the
    natural process.
    >
    > BTW, if you let your son learn to first balance his bicycle by lowering the seat, removing the
    > pedals and having him push it along 'hobby horse' style he can quickly learn to ride without any
    > falls. Once he can push off and coast for fairly long distances without touching his feet to the
    > ground you can reinstall the pedals and gradually raise the seat. Typically takes just a couple
    > hours and results in no skinned knees. {Of course those will likely come later anyway when he
    > practices jumping over bumps and taking corners too fast.)

    I think he has a more fundamental problem, he knows that when he can ride solo competently it's
    bye-bye trailer-bike.
     
  11. Matt Hiller

    Matt Hiller Guest

    In article <[email protected]>, epicyclist wrote:

    > I think he has a more fundamental problem, he knows that when he can ride solo competently it's
    > bye-bye trailer-bike.

    Huh? No need to say goodbye to the trailer bike just 'cause he can ride solo; the trailer-bike ought
    to be a good way to go on rides together without forcing you to ride well below your capacity just
    so he can stay caught up.
     
  12. Peter

    Peter Guest

    epicyclist wrote:
    > Peter wrote:
    >
    >> epicyclist wrote:
    >>
    >>> Peter wrote:
    >>>
    >>>> epicyclist wrote:
    >>>>
    >>>>> As I watch my little boy fight his bicycle and fall off in his transition from stabilisers to
    >>>>> free cycling I think "Gyroscopes". Yet many still say that balancing on a bike is a circus act
    >>>>> of steering correction. I can see that this effect becomes significant below 2mph just before
    >>>>> you fall off due to lack of forward velocity but why does the myth still prevail?
    >>>>
    >>>>
    >>>>
    >>>>
    >>>>
    >>>> Possibly because experiments have been done with counter-rotating wheels mounted on the bicycle
    >>>> to cancel gyroscopic effects. The bike still rides and steers about the same although I believe
    >>>> it did fall over faster when it was pushed and let go without a rider. Various modifications of
    >>>> the steering geometry were also tried and described in an article in "Physics Today" [wrong
    >>>> date].
    >>>>
    >>>>
    >>> Yes, they would not have made the grade for GCSE though would they?
    >>
    >>
    >>
    >> I suggest you read the article - the correct reference is David Jones, "Physics Today," April,
    >> 1970, pp34-40. The conclusion is that the bicycle has substantial inherent stability due to the
    >> steering geometry - so it is neither the result of gyroscopic forces nor a circus balancing act.
    >
    > Thankyou, as I remember it a lovely example of an uncontrolled experiment, hence my
    > comments about making the grade.

    It's actually a rather good example of making a hypothesis about a bicycle's stability and then
    conducting experiments to either prove or disprove the hypothesis. I believe a total of 5 different
    bicycles were constructed along with the original 'normal' model to see how changing gyroscopic
    factors and steering geometry affect the stability.

    >
    > The steering geometry provides stability, so that the active forces (gyroscopic) that come into
    > play when the bike deviates from the upright straight line will act to correct the situation.

    Your hypothesis was the first one tested. If true it would suggest that eliminating the gyroscopic
    forces would substantially reduce the stability of a ridden bicycle. The experiment showed that this
    was not the case - therefore the hypothesis is false. The steering geometry provides stability, but
    it does so even in the absence of gyroscopic effects.

    >
    >>
    >> BTW, if you let your son learn to first balance his bicycle by lowering the seat, removing the
    >> pedals and having him push it along 'hobby horse' style he can quickly learn to ride without any
    >> falls. Once he can push off and coast for fairly long distances without touching his feet to the
    >> ground you can reinstall the pedals and gradually raise the seat. Typically takes just a couple
    >> hours and results in no skinned knees. {Of course those will likely come later anyway when he
    >> practices jumping over bumps and taking corners too fast.)
    >
    >
    > I think he has a more fundamental problem, he knows that when he can ride solo competently it's
    > bye-bye trailer-bike.

    I doubt it. Children have a very strong innate desire to master new tasks. Unfortunately the
    traditional method of teaching them to ride a bicycle makes it much more difficult and painful than
    it needs to be.
     
  13. Tim Cain

    Tim Cain Guest

    "epicyclist" <[email protected]> wrote in message
    news:[email protected]...
    > B a r r y B u r k e J r . wrote:
    > > On Mon, 02 Jun 2003 09:13:26 +0100, epicyclist <[email protected]> wrote:
    > >
    > >
    > >>As I watch my little boy fight his bicycle and fall off in his transition from stabilisers to
    > >>free cycling I think "Gyroscopes". Yet many still say that balancing on a bike is a circus act
    > >>of steering correction. I can see that this effect becomes significant below 2mph just before
    > >>you fall off due to lack of forward velocity but why does the myth still prevail?
    > >
    > >
    > > How does a trackstanding rider stay up if the bike's wheels aren't moving?
    > >
    > > Barry
    > The same way I do when I stop dead at traffic lights, with a bit of help from the fixed wheel.

    How do I stop dead at the lights without a fixed wheel?

    Tim.

    ---
    Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com).
    Version: 6.0.487 / Virus Database: 286 - Release Date: 01/06/03
     
  14. Epicyclist

    Epicyclist Guest

    Tim Cain wrote:
    > "epicyclist" <[email protected]> wrote in message
    > news:[email protected]...
    >
    >>B a r r y B u r k e J r . wrote:
    >>
    >>>On Mon, 02 Jun 2003 09:13:26 +0100, epicyclist <[email protected]> wrote:
    >>>
    >>>
    >>>
    >>>>As I watch my little boy fight his bicycle and fall off in his transition from stabilisers to
    >>>>free cycling I think "Gyroscopes". Yet many still say that balancing on a bike is a circus act
    >>>>of steering correction. I can see that this effect becomes significant below 2mph just before
    >>>>you fall off due to lack of forward velocity but why does the myth still prevail?
    >>>
    >>>
    >>>How does a trackstanding rider stay up if the bike's wheels aren't moving?
    >>>
    >>>Barry
    >>
    >>The same way I do when I stop dead at traffic lights, with a bit of help from the fixed wheel.
    >
    >
    > How do I stop dead at the lights without a fixed wheel?
    >
    > Tim.
    If your like me you use the brakes to bring the bike to a standstill, shift your weight around a
    bit for a few seconds to try and stay up and if you haven't got your shoes out of the SPDs fall
    over onto your shoulder (making sure you don't put your hand out and so break your wrist).
    >
    >
    >
    > ---
    > Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com).
    > Version: 6.0.487 / Virus Database: 286 - Release Date: 01/06/03
     
  15. Tbgibb

    Tbgibb Guest

    In article <[email protected]>, epicyclist
    <[email protected]> writes:

    >As I watch my little boy fight his bicycle and fall off in his transition from stabilisers to free
    >cycling I think "Gyroscopes". Yet many still say that balancing on a bike is a circus act of
    >steering correction.

    When he does start riding on his own watch him from the distance, he'll be weaving from side to side
    as he corrects by steering.

    >I can see that this effect becomes significant below 2mph just before you fall off due to lack of
    >forward velocity but why does the myth still prevail?

    Mr. Brandt is fond of pointing out that people have no trouble riding a Ski-do, a bicycle type thing
    with skis instead of wheels. There is no gyroscope invloved there. If you want to test the gyro
    get your own bike up to speed and then steer right and lean left. Disclaimer: If you do you will
    fall and hurt yourself.

    Tom Gibb <[email protected]
     
  16. Robin Hubert

    Robin Hubert Guest

    "epicyclist" <[email protected]> wrote in message
    news:[email protected]...
    > Tim Cain wrote:
    > > "epicyclist" <[email protected]> wrote in message
    > > news:[email protected]...
    > >
    > >>B a r r y B u r k e J r . wrote:
    > >>
    > >>>On Mon, 02 Jun 2003 09:13:26 +0100, epicyclist <[email protected]> wrote:
    > >>>
    > >>>
    > >>>
    > >>>>As I watch my little boy fight his bicycle and fall off in his transition from stabilisers to
    > >>>>free cycling I think "Gyroscopes". Yet many still say that balancing on a bike is a circus
    > >>>>act of
    steering
    > >>>>correction. I can see that this effect becomes significant below 2mph just before you fall off
    > >>>>due to lack of forward velocity but why does the myth
    still
    > >>>>prevail?
    > >>>
    > >>>
    > >>>How does a trackstanding rider stay up if the bike's wheels aren't moving?
    > >>>
    > >>>Barry
    > >>
    > >>The same way I do when I stop dead at traffic lights, with a bit of help from the fixed wheel.
    > >
    > >
    > > How do I stop dead at the lights without a fixed wheel?
    > >
    > > Tim.
    > If your like me you use the brakes to bring the bike to a standstill, shift your weight around
    > a bit for a few seconds to try and stay up and if you haven't got your shoes out of the SPDs
    > fall over onto your shoulder (making sure you don't put your hand out and so break your
    wrist).

    No, just your clavicle.

    --
    Robin Hubert <[email protected]
     
  17. epicyclist <[email protected]> writes:

    [...]

    > I can see that this effect becomes significant below 2mph just before you fall off due to lack of
    > forward velocity but why does the myth still prevail?

    The answer can be found in the FAQ:

    http://draco.acs.uci.edu/rbfaq/FAQ/9.35.html

    And there's of course Jones' article, that others mentioned.

    There are also many experiments that one could do to check whether gyroscopic forces really
    matter. For example, you could try to modify your bike to lock the steering. If you are right,
    such a bike should be ridable on a straight descent, provided you use your feet to keep balance at
    very low speed.

    Michel.
     
  18. Andy Dingley

    Andy Dingley Guest

    On Mon, 02 Jun 2003 21:31:28 +0100, epicyclist <[email protected]> wrote:

    >and if you haven't got your shoes out of the SPDs fall over onto your shoulder (making sure you
    >don't put your hand out and so break your wrist).

    Practice aikido beforehand. Then your natural reaction to falling over tends to be rolling. It
    doesn't hurt, but if you still have a bike clipped to your feet you'll roll onto your back with your
    wheels in the air, like some great wheeled beetle.

    (My second traffic light after first using SPDs)
     
  19. On Mon, 02 Jun 2003 21:31:28 +0100, epicyclist <[email protected]> wrote:

    > If your like me you use the brakes to bring the bike to a standstill, shift your weight around a
    > bit for a few seconds to try and stay up and if you haven't got your shoes out of the SPDs fall
    > over onto your shoulder (making sure you don't put your hand out and so break your wrist).
    >

    Do you know what a trackstand is?

    The wheels aren't turning, your feet are still clipped in, and you don't fall over.

    There is nothing potentially gyroscopic going on.

    Barry
     
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