Circus acts

epicyclist said:

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.

Peter said:

epicyclist said:

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?

epicyclist said:

Peter said:

epicyclist said:

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.)

epicyclist said:

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

Peter said:

epicyclist said:

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

Peter said:

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

B a r r y B u r k e J r . said:

epicyclist said:

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.

Kit Wolf said:

Peter said:

epicyclist said:

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.

Peter said:

epicyclist said:

Peter said:

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.

Quoted message said:

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.

In article said:

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.

epicyclist said:

Peter said:

epicyclist said:

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.

Quoted message said:

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.

Quoted message said:

Quoted message said:

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.

"epicyclist" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

B a r r y B u r k e J r . said:

epicyclist said:

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.

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Tim Cain said:

"epicyclist" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

B a r r y B u r k e J r . said:

On Mon, 02 Jun 2003 09:13:26 +0100, epicyclist <[email hidden]> 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).

Quoted message said:

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In article <[email hidden]>, epicyclist

Quoted message said:

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.

Quoted message said:

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 hidden]

"epicyclist" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

Tim Cain said:

"epicyclist" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

B a r r y B u r k e J r . wrote:

>On Mon, 02 Jun 2003 09:13:26 +0100, epicyclist <[email hidden]> 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

Quoted message said:

Quoted message said:

Quoted message said:

>>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

Quoted message said:

Quoted message said:

Quoted message said:

>>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 hidden]

Peter <[email hidden]> writes:

[...]

Quoted message said:

I suggest you read the article - the correct reference is David Jones, "Physics Today," April,
1970, pp34-40.

FYI, it's available on the Web as a (huge) PDF scan, there:

ist-socrates.berkeley.edubicycles.htmlOpen ↗

There are other informations about bicycle steering on this page.

Michel.

epicyclist <[email hidden]> writes:

[...]

Quoted message said:

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:

draco.acs.uci.edu9.35.htmlOpen ↗

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.

epicyclist said:

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)

epicyclist said:

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