Turning without countersteering: photographs and test results

Eiron

Paul - xxx wrote:

> Seems odd, then, that all the 'throwing of hips to one side' is always to
> the side into which you're leaning a motorcycle when racing ... and I have
> done that hands off too and got round the corner ..
> http://www.manxnewcomers.com/rons2000withwendy.jpg
> Note which way the bikes handlebars are turning .. and which way the rider
> is leaning, similarly the rider behind, though it is a litle awkward to see
> past the first ..

You are in the wrong thread.
This discussion is about how to initiate a turn, or if already in a
turn, how to change the radius of the turn.

It is not about whether motorcycles oversteer or whether your
bum looks big in those leathers on your girly little motorcycle.

--
Eiron.

Nick Kew

In article <32fi4eF3momifU1@individual.net>,
Eiron <e1ron@hotmail.com> writes:

> The track of the front wheel is clearly visible to the right...
> ...at the start of a left turn. Is this not countersteering?

Certainly not. That's just the rear wheel following the shortest path
to where the front wheel now is, and thus cutting the corner.

--
Nick Kew

Paul - xxx

Eiron composed the following ...
> Paul - xxx wrote:
>
>> Seems odd, then, that all the 'throwing of hips to one side' is always to
>> the side into which you're leaning a motorcycle when racing ... and I
>> have done that hands off too and got round the corner ..
>> http://www.manxnewcomers.com/rons2000withwendy.jpg
>> Note which way the bikes handlebars are turning .. and which way the
>> rider is leaning, similarly the rider behind, though it is a litle
>> awkward to see past the first ..
>
> You are in the wrong thread.
> This discussion is about how to initiate a turn, or if already in a
> turn, how to change the radius of the turn.

But to initiate a turn I don't 'throw my hips to the right for a left turn
at all, quite the opposite.

> It is not about whether motorcycles oversteer or whether your
> bum looks big in those leathers on your girly little motorcycle.

It's not my motorcycle, merely the first picture of one which looked like it
was in a turn that I found googling. My motorcycles (I have more than one)
are smaller, and bigger than that one ..

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

Chris Malcolm

"Paul - xxx" <notcheckedever@hotmail.com> writes:

>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.

Which is completely different because three wheelers can't tip.

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

>Yes.

It's not a human instinctive compensation, it's a natural effect of
the laws of physics. Stick your arm out to the left on a bike and the
whole ensemble of bike and body tips to the right in automatic
physical reaction which causes the CofG to remain in the same place.

It's a good job people don't have to understand how to do it in order
to ride bicycles!

--
Chris Malcolm cam@infirmatics.ed.ac.uk +44 (0)131 651 3445 DoD #205
IPAB, Informatics, JCMB, King's Buildings, Edinburgh, EH9 3JZ, UK
[http://www.dai.ed.ac.uk/homes/cam/]

Paul - xxx

Chris Malcolm composed the following ...
> "Paul - xxx" <notcheckedever@hotmail.com> writes:
>
>> 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.
>
> Which is completely different because three wheelers can't tip.

Wwanna bet .. It was a light-hearted response and not in any way an
addition to the thread topic, as such.

>>> The question is whether
>>> you can shift your centre of gravity to the side without instinctively
>>> compensating.
>
>> Yes.
>
> It's not a human instinctive compensation, it's a natural effect of
> the laws of physics. Stick your arm out to the left on a bike and the
> whole ensemble of bike and body tips to the right in automatic
> physical reaction which causes the CofG to remain in the same place.

If I stick my arm out surely the centre of balance moves slightly with the
arm. And forgetting wind resistance of course ..

If I stick my arm out whilst standing I do not move to the right to
compensate. It's a muscular action, with forces that occur around the bone
structure and through the body. Same on a bike. Stick arm out left and the
bike will move to the left, fall over ineffect.

Sod it, I've had enough of this.

I disagree that one needs to counter-steer to initiate a turn on a bicycle
or motorcycle. It is done, I do it, but it isn't necessary.

I doubt anyone can or will persuade me otherwise.

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

Chris Malcolm

Simon Brooke <simon@jasmine.org.uk> writes:

>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?

You don't have to do any shifting, you simply have to stop correcting
wobbles to the required side of lean. It happens sooner or later, but
not, as you may have observed, exactly when you want it to happen.

To turn a corner on a bike you have to get it to start falling to the
required side. Theere are a number of ways of doing, of which the
easiest and fastest is to shift the wheel contact line from under the
CofG by turning the bars the other way, usually only very slightly and
briefly. You then undercorrect the fall by not turning the bars enough
into the turn until the lean is as much as required, at which point
you bring in the fully compensated bar turn which balances turn with
centrifugal force.

You do the same thing in reverse to rise up out of the turn.

And you do the same thing with your feet and CofG when running round a
corner.

It's nothing specially to with bikes. Same with skates and skis. It's
the physics of a tall thing with a narrow left-to-right contact patch
turning a corner.

--
Chris Malcolm cam@infirmatics.ed.ac.uk +44 (0)131 651 3445 DoD #205
IPAB, Informatics, JCMB, King's Buildings, Edinburgh, EH9 3JZ, UK
[http://www.dai.ed.ac.uk/homes/cam/]

Chris Malcolm

Simon Brooke <simon@jasmine.org.uk> writes:

>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_.

No, inertia is one of the crucial components of making it happen.

>> 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.

It's much simpler than that. It's simply that the faster you're going,
the faster a given turn of the bars causes the contact patch to shift
to the side of the CofG. *Because* of inertia. So the amount of turn
needed to get the bike to lean a certain amount to one side in a given
time is inversely proportional to speed. So the faster you go, the
less correction is needed, because your speed amplifies the effect of
a given bar turn.

--
Chris Malcolm cam@infirmatics.ed.ac.uk +44 (0)131 651 3445 DoD #205
IPAB, Informatics, JCMB, King's Buildings, Edinburgh, EH9 3JZ, UK
[http://www.dai.ed.ac.uk/homes/cam/]

Chris Malcolm

Simon Brooke <simon@jasmine.org.uk> writes:

>However, Newton would have been the first to point out that you _can_
>move your centre of gravity, briefly, by exploiting inertia.

Nope. I think you think inertia means that if you stick your arm out
to the left your CofG shifts to the left, briefly, before you or
something compensates. But what Newton's laws of motion actually cause
to happen is a perfect compensation so that the CoG stays in the same
place. Otherwise you'd be able to move about in space just by waving
your arms, without having to bung stuff away, as in rockets.
--
Chris Malcolm cam@infirmatics.ed.ac.uk +44 (0)131 651 3445 DoD #205
IPAB, Informatics, JCMB, King's Buildings, Edinburgh, EH9 3JZ, UK
[http://www.dai.ed.ac.uk/homes/cam/]

Chris Malcolm

"Paul - xxx" <notcheckedever@hotmail.com> writes:

>What about the force exerted by the frictio of the tyre against the road?
>When you lean left to turn left, with no steering input, the tyre tries to
>push right, but the road exerts frictional forces, pushing it back, thus you
>start to fall over, when the cycle geometry takes over and steers away from
>straight to the left. Note, the steering hasn't gone to the right in any
>way, shape or form.. If you leaned left on ice, with no steering input, the
>tyre (and bicycle and you) would slide away to the right.

I'm sorry, Paul, but either you never did sums involving Newton's Laws
of Motion in mathematical physics, or you've forgotten them. The
reason it took Newton to invent them after thousands of years of
intelligent speculation is that they're *not* intuitively
obvious. Anyone who can remember the class in which Newton's Laws of
Motion were first introduced must be able to remember how outraged
some people were at this insult to common sense, how hard it was for
some people to grasp them, and how some people never ever managed to
get it.

--
Chris Malcolm cam@infirmatics.ed.ac.uk +44 (0)131 651 3445 DoD #205
IPAB, Informatics, JCMB, King's Buildings, Edinburgh, EH9 3JZ, UK
[http://www.dai.ed.ac.uk/homes/cam/]

dkahn400

Paul - xxx wrote:

> er .. friction of tyre on road surface.

It doesn't help your case. Friction with the ground is what causes the
bike to lean in the opposite direction to the rider. The tyre contact
point provides a pivot. The masses moving left and right from the C of
G must be the same. If the tyre is very wide and flat the situation its
changed somewhat as it will then provide some resistance to the lean.
Is this possibly what you have in mind?

--
Dave...

David Martin

On 17/12/04 11:08 am, in article
1103281692.622397.122320@f14g2000cwb.googlegroups.com, "dkahn400"
<dkahn400@yahoo.co.uk> wrote:

>
> Paul - xxx wrote:
>
>> er .. friction of tyre on road surface.
>
> It doesn't help your case. Friction with the ground is what causes the
> bike to lean in the opposite direction to the rider. The tyre contact
> point provides a pivot. The masses moving left and right from the C of
> G must be the same. If the tyre is very wide and flat the situation its
> changed somewhat as it will then provide some resistance to the lean.
> Is this possibly what you have in mind?

What about a swing? Surely it is impossible for a swing to start moving from
rest if there is always a net resultant of 0.

...d

dkahn400

Paul - xxx wrote:

> What about the force exerted by the friction of the tyre against
> the road? When you lean left to turn left, with no steering
> input, the tyre tries to push right, but the road exerts
> frictional forces, pushing it back, thus you start to fall over,
> when the cycle geometry takes over and steers away from
> straight to the left.

The contact patch of the tyre is below the bike's C of G. A push to the
left at this point will cause the bike to rotate around its C of G. It
will therefore make it lean to the right, not the left.

--
Dave...

dkahn400

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

> > 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 what you have described sounds like classic countersteering. Think
about "as you lean the bike over". The way to make this happen is to
lean in the opposite direction. I lean to the left and the bike leans
to the right. It steers to the right providing the countersteering
necessary to move the contact patch to the right of the C of G just as
you described.

--
Dave...

Clive George

"David Martin" <d.m.a.martin@dundee.ac.uk> wrote in message
news:BDE8722F.5F2F%d.m.a.martin@dundee.ac.uk...

> What about a swing? Surely it is impossible for a swing to start moving
from
> rest if there is always a net resultant of 0.

In the absence of friction is this the case? Would a swing work on the moon?

cheers,
clvie