Turning without countersteering: photographs and test results

Paul - xxx

dkahn400 composed the following ...
> Paul - xxx wrote:
>> "dkahn400 composed the following ...
>>> The C of G is still inside the track of the wheels. You still
>>> have to account for how the rider managed to move his C of G
>>> to one side.
>>
>> errr by moving his legs, arms, feet, body.
>
> Newton's third law. If you move part of your body to your left there
> must be an equal reaction to the right. Because you have nothing to
> push against, something else must move to the right.

Friction between tyre and road, force exerted, pushes whole shebang over.
Body leans back up some way to stop it falling and bike continues to go in
circle ..

> When you stick
> your left arm out to signal the bike doesn't start a turn by itself.
> What happens is that your bike and body incline slightly to the right
> and you carry on in a straight line. Your centre of gravity remains
> stubbornly above the line between the two contact patches.

Yes, I agree, but if you merely stick your arm out without doing the "bike
and body incline slightly to the right" bit, then the bike will start to
fall over .. then you do the "bike and body incline slightly to the right"
to balance and hey presto, cycling into a radius without counter steering.

>> What about no-handed riding?
>
> If I want to turn left I lean to the left, the bicycle leans initially
> to the right, the bars turn slightly to the right giving the necessary
> countersteer to move the contact patch to the right of the C of G. The
> bicycle then leans to the left and the wheel turns left as it begins a
> smooth turn.

I disagree.

What the hell, it's a small world and it's be a shame if some of us can't
disagree of some things. I disagree that we _MUST_ countersteer to initiate
a turn on a bicycle. I have seen nothing to disprove what I think.

nuff sed ..

--
Paul ...
http://www.4x4prejudice.org/index.php
(8(!) Homer Rules ...
"A tosser is a tosser, no matter what mode of transport they're using."

Paul - xxx

Patrick Herring composed the following ...

> You can in motorbike sidecar racing stylee.

Of which I have extensive experience and practice ..
http://groups.msn.com/LosiPaulsPict...hoto&PhotoID=28
I had been racing then for about four years.

> The question is whether
> you can shift your centre of gravity to the side without instinctively
> compensating.

Yes.

--
Paul ...
http://www.4x4prejudice.org/index.php
(8(!) Homer Rules ...
"A tosser is a tosser, no matter what mode of transport they're using."

Clive George

"Paul - xxx" <notcheckedever@hotmail.com> wrote in message
news:32e9beF3ko27lU1@individual.net...

> > Newton's third law. If you move part of your body to your left there
> > must be an equal reaction to the right. Because you have nothing to
> > push against, something else must move to the right.
>
> Friction between tyre and road, force exerted, pushes whole shebang over.
> Body leans back up some way to stop it falling and bike continues to go in
> circle ..

Haven't you just described countersteering?

cheers,
clive

Paul - xxx

Clive George composed the following ...
> "Paul - xxx" <notcheckedever@hotmail.com> wrote in message
> news:32e9beF3ko27lU1@individual.net...
>
>>> Newton's third law. If you move part of your body to your left there
>>> must be an equal reaction to the right. Because you have nothing to
>>> push against, something else must move to the right.
>>
>> Friction between tyre and road, force exerted, pushes whole shebang over.
>> Body leans back up some way to stop it falling and bike continues to go
>> in circle ..
>
> Haven't you just described countersteering?

Nope.

Where did I mention turning the bars ?

Body leans left, bike follows and leans left, body shifts right to
compensate, equilibrium maintained whilst circling.

--
Paul ...
http://www.4x4prejudice.org/index.php
(8(!) Homer Rules ...
"A tosser is a tosser, no matter what mode of transport they're using."

Clive George

"Paul - xxx" <notcheckedever@hotmail.com> wrote in message
news:32ebtoF3lr7n2U1@individual.net...
> Clive George composed the following ...
> > "Paul - xxx" <notcheckedever@hotmail.com> wrote in message
> > news:32e9beF3ko27lU1@individual.net...
> >
> >>> Newton's third law. If you move part of your body to your left there
> >>> must be an equal reaction to the right. Because you have nothing to
> >>> push against, something else must move to the right.
> >>
> >> Friction between tyre and road, force exerted, pushes whole shebang
over.
> >> Body leans back up some way to stop it falling and bike continues to go
> >> in circle ..
> >
> > Haven't you just described countersteering?
>
> Nope.
>
> Where did I mention turning the bars ?
>
> Body leans left, bike follows and leans left, body shifts right to
> compensate, equilibrium maintained whilst circling.

Er - the thing is, the bar moving just happens, even if you're not directly
asking it to.
Body leans left, bike leans right - it has to, to compensate for your left
lean, since you don't actually provide a sideways force with your lean.
However you won't necessarily observe this happening, as it's a very tiny
effect. Contact patch moves to the right, then the bike leans left and body
right to compensate and lo, you're in your turn.

Remember, countersteering isn't necessarily about explicitly turning the
bars.

cheers,
clive

Simon Brooke

in message <Xns95C188FE68913pleasegivegenerously@130.133.1.4>, Mark
Thompson ('pleasegivegenerously@warmmail.com') wrote:

>> In order to turn left, you start by turning the handlebars to
>> the
>> right for a moment. This moves the front wheel out to the right of
>> the center of gravity, so the bike will start to fall to the left.
>> This is immediately follwed by turning the handlebars to the left to
>> cause the bike to remain in balance, which also creates the desired
>> left turn. "Countersteering" refers to the momentary motion of the
>> handlebars in the opposite direction of the desired turn.
>
> So the only reason we countersteer is to lean the bike over? If we
> can also lean the bike over just by shifting our weight then a
> countersteer is
> not necessary to initiate a turn. The question is, is it possible to
> shift our body to the side without also turning the handlbars?

How do you ride a bike no hands?

--
simon@jasmine.org.uk (Simon Brooke) http://www.jasmine.org.uk/~simon/

The Conservative Party is now dead. The corpse may still be
twitching, but resurrection is not an option - unless Satan
chucks them out of Hell as too objectionable even for him.

Simon Brooke

in message <cpsid7$9d8$1@scotsman.ed.ac.uk>, Chris Malcolm
('cam@holyrood.ed.ac.uk') wrote:

> Mark Thompson <pleasegivegenerously@warmmail.com> writes:
>
>>I think we can shift our bodyweight to lean the bike and initiate a
>>turn without needing to countersteer.
>
> Isaac Newton disagrees with you. The problem is that shifting any part
> of your body to one side automatically shifts the rest in reaction in
> just such a way that the orientation of the perpendicular from the
> CofG to the line of the contact patch with respect to gravity is
> preserved.

That's true, _ignoring_ _inertia_.

> It is possible to very clever with relative accelerations and
> distances above the contact patch to defeat this equilibrium, but it
> is a hard trick to learn, e.g. the small number of people who can
> balance on a stationary bike (a bike which is rolling back and forth a
> bit is not stationary).

Yebbut, a moving bicycle is an interesting set of feedback mechanisms
and servos. The control inputs necessary to correct an out of balance
condition on a moving bike are orders of magnitude smaller than the
control inputs required to correct a similar out-of-balance
displacement of a stationary bicycle. That is (in my opinion) why it's
easier to balance a moving bike than a stationary one.

--
simon@jasmine.org.uk (Simon Brooke) http://www.jasmine.org.uk/~simon/

;; Life would be much easier if I had the source code.

Simon Brooke

in message <32dirkF3ko1epU1@individual.net>, Clive George
('clive@xxxx-x.fsnet.co.uk') wrote:

> I think what you think of as steering without counter-steering is
> merely steering withough explicitly countersteering - during the
> normal course of riding in a straight line, the bike wobbles a little
> tiny bit, and all you do is unconsciously use one of those wobbles to
> provide the necessary countersteer to initiate your turn.

This is a statement of religious faith, not of knowledge, and in part an
argument about dancing angels. Yes, a moving bike tends to oscillate
around the point of balance, and it's possibly true that all moving
bikes are always oscillating (if only very slightly). If you are
prepared to go far enough back into the past, before every turn to the
right there was an oscillation to the left, and vice versa. To claim
that any such oscillation is causative of the turn or required to make
the turn is nonsense, however.

There are number of ways in which, on a theoretical perfectly stable
non-oscillating bike, the rider can initiate a turn. One is the
exploitation of inertia, which I've discussed above. But if you don't
believe in inertia, consider aerodynamics. If you turn your torso you
inevitably create some shift in the aerodynamic forces acting on your
body, and some component of those forces will be at right angles to
your track. Try it: find a long steady hill, get up to a speed at which
it's comfortable to ride no hands, ride no hands, move your torso until
your shoulders are about 45 degrees to your track first one side, then
the other. What happens?

Once again, no one is saying that counter steering doesn't work. All I
(and others) are saying is that it's not necessary.

--
simon@jasmine.org.uk (Simon Brooke) http://www.jasmine.org.uk/~simon/

my other car is #<Subr-Car: #5d480>
;; This joke is not funny in emacs.

James Annan

Simon Brooke wrote:

> in message <32bqmjF3kgpqdU1@individual.net>, James Annan
> ('still_the_same_me@hotmail.com') wrote:
>
>
>>http://www.ne.jp/asahi/julesandjame...tersteering.jpg
>
>
> Interesting that at the point you mark the track of the front wheel is
> clearly visible to the right of the track of the back. Face it, you
> cannot mark the point of countersteer, because it _did_ _not_ _happen_.

I cannot clearly identify much, because the tracks are very indistinct.

Let's cut to the quick: can you identify a reason why your proposed
ability to move your CoG from side to side at will cannot balance a
non-steering bicycle? If not, you must be claiming that basically
everything that everyone has ever written about bicycle control is wrong.

James
--
If I have seen further than others, it is
by treading on the toes of giants.
http://www.ne.jp/asahi/julesandjames/home/

Simon Brooke

in message <1103213385.640040.70740@c13g2000cwb.googlegroups.com>,
dkahn400 ('dkahn400@yahoo.co.uk') wrote:

> Paul - xxx wrote:
>> "dkahn400 composed the following ...
>> > The C of G is still inside the track of the wheels. You still
>> > have to account for how the rider managed to move his C of G
>> > to one side.
>>
>> errr by moving his legs, arms, feet, body.
>
> Newton's third law. If you move part of your body to your left there
> must be an equal reaction to the right. Because you have nothing to
> push against, something else must move to the right. When you stick
> your left arm out to signal the bike doesn't start a turn by itself.
> What happens is that your bike and body incline slightly to the right
> and you carry on in a straight line. Your centre of gravity remains
> stubbornly above the line between the two contact patches.

No it doesn't, because a bike has steering which responds to gravity. So
as you lean the bike over, it steers towards the side you lean it
towards, initiating a turn in that direction, and moving the contact
patch out from under the CoG. This is precisely the argument used to
'prove' that counter-steering is necessary. And James (passim) is
perfectly right to observe that as you lean the bike to the side, you
are moving the track out from under your CoG, unless you moved your CoG
first.

However, Newton would have been the first to point out that you _can_
move your centre of gravity, briefly, by exploiting inertia. Obviously
there's a limit to how how much displacement you can achieve in this
way, but a moving bicycle is a finely balanced and responsive machine
so you don't have to move it very much or for very long. So if you move
your CoG first, the bike will automatically turn to bring the track
back under it; and that is at least one method of riding no hands.


--
simon@jasmine.org.uk (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

Paul - xxx

Clive George composed the following ...
> "Paul - xxx" <notcheckedever@hotmail.com> wrote in message
> news:32ebtoF3lr7n2U1@individual.net...
>> Clive George composed the following ...
>>> "Paul - xxx" <notcheckedever@hotmail.com> wrote in message
>>> news:32e9beF3ko27lU1@individual.net...
>>>
>>>>> Newton's third law. If you move part of your body to your left there
>>>>> must be an equal reaction to the right. Because you have nothing to
>>>>> push against, something else must move to the right.
>>>>
>>>> Friction between tyre and road, force exerted, pushes whole shebang
>>>> over. Body leans back up some way to stop it falling and bike
>>>> continues to go in circle ..
>>>
>>> Haven't you just described countersteering?
>>
>> Nope.
>>
>> Where did I mention turning the bars ?
>>
>> Body leans left, bike follows and leans left, body shifts right to
>> compensate, equilibrium maintained whilst circling.
>
> Er - the thing is, the bar moving just happens, even if you're not
> directly asking it to.
> Body leans left, bike leans right

Nope, bike follows body, both move simultaneously.

> - it has to, to compensate for your left
> lean, since you don't actually provide a sideways force with your lean.

er .. friction of tyre on road surface.

Sorry, I earlier said 'nuff said' .. I'm going to stick to that as I don't
think you'll persuade me and likewise I don't think I'll persuade you.

I just happen to be right ..

--
Paul ...
http://www.4x4prejudice.org/index.php
(8(!) Homer Rules ...
"A tosser is a tosser, no matter what mode of transport they're using."

James Annan

Paul - xxx wrote:

> Clive George composed the following ...
>
>>"Paul - xxx" <notcheckedever@hotmail.com> wrote in message
>>news:32di9uF3kbf6lU1@individual.net...
>>
>>>James Annan composed the following ...
>>>
>>>>James Annan wrote:
>>>>
>>>>
>>>>> From "Steering in bicycles and motorcycles", J. Fajans, Am. J. Phys.
>>>>>68
>>>>
>>>>
>>>>That's annoying. Half my post vanished. The full ref is Vol 68 No 7, pp
>>>>654-659, 2000.
>>>>
>>>>And the quote taken directly from the abstract was supposed to be:
>>>>
>>>>"Steering a motorcycle or bicycle is counterintuitive; to turn right,
>>>>you must steer left initially, and vice versa. You can execute this
>>>>initially counter-directed turn by turning the handlebars explicitly
>>>
>>>I disagree that we 'must' use countersteering .. when we can obviously
>>>also steer without counter-steering.
>>
>>I think what you think of as steering without counter-steering is merely
>>steering withough explicitly countersteering - during the normal course of
>>riding in a straight line, the bike wobbles a little tiny bit, and all you
>>do is unconsciously use one of those wobbles to provide the necessary
>>countersteer to initiate your turn.
>
>
> I guess we'll have to disagree then ..
>

If you can do what you claim, you would also be able to balance a
non-steering bicycle. That seems to me to be the most direct proof that
this idea of Simon's is nonsense.

James
--
If I have seen further than others, it is
by treading on the toes of giants.
http://www.ne.jp/asahi/julesandjames/home/

James Annan

Paul - xxx wrote:


> What about no-handed riding? I can use knees, thighs, feet etc to weight or
> un-weight a pedal, side of seat, etc all without hands on the bars and still
> turn a corner. Lean over, witt hands still off the bars, and the bike will
> lean over and initiate it's own turn. The body can then straighten slightly
> to balance, and the bike will continue that turn. All no hands on bars, all
> achieved with no countersteering."

As Fajans writes:

Alternately, the required lean can be generated by throwing your hips in
the direction counter to the turn. Throwing your hips is how a bike is
steered no-hands. The sign of the effect is subtle, but a half-hour
session in an empty parking lot should convince you that while riding
no-handed, you steer the bike by leaning your shoulders in the direction
of the desired turn. Since angular momentum is conserved by a sudden
shift of your shoulders, your hips move the opposite way, thereby
leaning the bike the opposite way as well. With the bike now leaning,
the bike’s "trail" becomes important. As the steering axis is not
vertical, the point of contact of the wheel with the road "trails" the
intersection of the steering axis with the road (see fig 1a). The trail
makes the bike self-steer: when the bike leans to the left, the front
wheel steers left; when the bike leans to the right, the front wheel
steers right. This effect is easily demonstrated by standing beside a
bicycle and leaning it from side to side. The trail is the single most
important geometric parameter which enters into the handling of a bicycle.)
The complete hip-turn sequence is similar to the countersteer sequence
illustrated in Fig. 1, except that you initiate the turn by throwing
your hips left. The bike leans left as well, and the trail steers the
wheel left. Centrifugal torques then lean the center of mass to the
right, and gyroscopic forces eventually steer the wheel right.


Hope that helps, (and hope it isn't cut off in posting!)

James
--
If I have seen further than others, it is
by treading on the toes of giants.
http://www.ne.jp/asahi/julesandjames/home/

James Annan

Paul - xxx wrote:


> Sorry, I earlier said 'nuff said' .. I'm going to stick to that as I don't
> think you'll persuade me and likewise I don't think I'll persuade you.
>
> I just happen to be right ..

No, you happen to be invincibly ignorant. But never mind, as my wife
reminded me only yesterday, only a few centuries ago no-one knew
anything at all about Newton's laws, so I shouldn't be too hard on a few
laggards who still don't understand them now.

James
--
If I have seen further than others, it is
by treading on the toes of giants.
http://www.ne.jp/asahi/julesandjames/home/