My Experiment...

[Tony B]

Cycled into school today with 4yo, deep joy... anyway, apart from that,
when I was walking my velo through the school yard I had hold of the
seat in a very cool sort of way (for the benefit of the local yummy
mummies natch (1)) and had a porridge inspired brainwave to try a
counter steering experiment. So, walk along, holding velo by saddle, and
push said velo to one side (either will do). Observe what happens to the
front end during the push. On my (well, Mrs B's actually) Ridgeback
Nemesis the front very clearly and definitely turns left if I push the
saddle to the right (and vice versa). Now, that's experimental science!!
Dunno what it means though. I once had a motorcycle engineering text
book that would doubtless explain it better than me, but I guess no-one
would believe a word of it anyway.

Counter steering on a motorcycle is a fascinating technique; the machine
fair whips into turns if you give it a bit of opposite knock. Keith Code
(a famous Californian race instructor) was very big into counter steer
IIRC. As was Rainey, Schwantz et. al. When I tried deliberately counter
steering on the way home from school I didn't notice quite the same
effect. But then I go bored and concentrated on pissing off (2) all the
tossers in X5's, sat doing nothing....

Tony B

1) OK then, the local Vicky Pollards....

2) OK then, riding past them and making good progress...

 

[Roger Thorpe]

Tony B wrote:
> Cycled into school today with 4yo, deep joy... anyway, apart from that,
> when I was walking my velo through the school yard I had hold of the
> seat in a very cool sort of way (for the benefit of the local yummy
> mummies natch (1)) and had a porridge inspired brainwave to try a
> counter steering experiment. So, walk along, holding velo by saddle, and
> push said velo to one side (either will do). Observe what happens to the
> front end during the push. On my (well, Mrs B's actually) Ridgeback
> Nemesis the front very clearly and definitely turns left if I push the
> saddle to the right (and vice versa). Now, that's experimental science!!
> Dunno what it means though. I once had a motorcycle engineering text
> book that would doubtless explain it better than me, but I guess no-one
> would believe a word of it anyway.
>
> Counter steering on a motorcycle is a fascinating technique; the machine
> fair whips into turns if you give it a bit of opposite knock. Keith Code
> (a famous Californian race instructor) was very big into counter steer
> IIRC. As was Rainey, Schwantz et. al. When I tried deliberately counter
> steering on the way home from school I didn't notice quite the same
> effect. But then I go bored and concentrated on pissing off (2) all the
> tossers in X5's, sat doing nothing....
>
> Tony B
>
> 1) OK then, the local Vicky Pollards....
>
> 2) OK then, riding past them and making good progress...

There's something very satisfying about pushing the bike by the saddle,
a sure test of a headset.
Ok, the thing that I'm not exactly clear about steering is this:
I find that sticking my knee out when going round a tight corner enables
me to adjust the radius of the turn by bringing it in . Is it just me?
Roger Thorpe

 

[Paul Boyd]

On 23/02/2007 19:01, Roger Thorpe said,

> Ok, the thing that I'm not exactly clear about steering is this:
> I find that sticking my knee out when going round a tight corner enables
> me to adjust the radius of the turn by bringing it in . Is it just me?

Nope - assuming you mean the knee on the inside of the corner. Sticking
it out means you can corner sharper/faster, bringing it in will relax
the corner. The only problem I find is that my SPDs unclip :-(

--
Paul Boyd
http://www.paul-boyd.co.uk/

 

[Pete Biggs]

Tony B wrote:
> Cycled into school today with 4yo, deep joy... anyway, apart from
> that, when I was walking my velo through the school yard I had hold
> of the seat in a very cool sort of way (for the benefit of the local
> yummy mummies natch (1)) and had a porridge inspired brainwave to try
> a counter steering experiment. So, walk along, holding velo by
> saddle, and push said velo to one side (either will do). Observe what
> happens to the front end during the push. On my (well, Mrs B's
> actually) Ridgeback Nemesis the front very clearly and definitely
> turns left if I push the saddle to the right (and vice versa). Now,
> that's experimental science!! Dunno what it means though. I once had
> a motorcycle engineering text book that would doubtless explain it
> better than me, but I guess no-one would believe a word of it anyway.
>
> Counter steering on a motorcycle is a fascinating technique; the
> machine fair whips into turns if you give it a bit of opposite knock.
> Keith Code (a famous Californian race instructor) was very big into
> counter steer IIRC. As was Rainey, Schwantz et. al. When I tried
> deliberately counter steering on the way home from school I didn't
> notice quite the same effect. But then I go bored and concentrated on
> pissing off (2) all the tossers in X5's, sat doing nothing....

Theory goes that you can steer only by counter-steering first, and that you
do it subconciously. See http://sheldonbrown.com/brandt/gyro.html

It certainly happens at low speed. Ride through a puddle, turn left
normally, go back and have a look at your tyre tracks.

~PB

 

[Pete Biggs]

Another link:

http://www.sheldonbrown.com/brandt/descending.html :

"What is not apparent, is that two wheeled vehicles can be controlled ONLY
by countersteer, there is no other way. Unlike a car, a bicycle cannot be
diverted from a straight path by steering the wheel to one side. The bicycle
must first be leaned in that direction by steering it ever so slightly the
other way. This is the means by which a broomstick is balanced on the palm
of the hand or a bicycle on the road. The point of support is moved beneath
the mass, in line with the combined forces of gravity and cornering, and it
requires steering, counter and otherwise. It is so obvious that runners
never mention it, although football, basketball, and ice hockey players
conspicuously do it."

 

[Ian Smith]

On Fri, 23 Feb, Pete Biggs <> wrote:
> Another link:
>
> http://www.sheldonbrown.com/brandt/descending.html :
> "What is not apparent, is that two wheeled vehicles can be
> controlled ONLY by countersteer, there is no other way.

Which means, presumably, that it's completely impossible for me to
steer while riding no-handed.

OK, as long as no-one tells my bike, I'll just carry on doing it and
we'll be fine.

How do the 'you can only turn by shoving the bars the wrong way' and
'leaning a bike won't make it turn' lot explain the ability to ride
no-hands in other than straight lines?

regards, Ian SMith
--
|\ /| no .sig
|o o|
|/ \|

 

[Pete Biggs]

Ian Smith wrote:
>>
>> http://www.sheldonbrown.com/brandt/descending.html :
>> "What is not apparent, is that two wheeled vehicles can be
>> controlled ONLY by countersteer, there is no other way.
>
> Which means, presumably, that it's completely impossible for me to
> steer while riding no-handed.
>
> OK, as long as no-one tells my bike, I'll just carry on doing it and
> we'll be fine.
>
> How do the 'you can only turn by shoving the bars the wrong way' and
> 'leaning a bike won't make it turn' lot explain the ability to ride
> no-hands in other than straight lines?

You steer by moving your body, whether you have your hands on the bars or
not.

~PB

 

[Pete Biggs]

Ian Smith wrote:

> How do the 'you can only turn by shoving the bars the wrong way' and
> 'leaning a bike won't make it turn' lot explain the ability to ride
> no-hands in other than straight lines?

They don't say you shove the bars, they say you lean your body in such a way
at such a time that will make the wheel twitch right when you want to turn
left. Or something like that.

Try the puddle test no-handed.

~PB

 

[Roger Thorpe]

Paul Boyd wrote:

> On 23/02/2007 19:01, Roger Thorpe said,
>
>> Ok, the thing that I'm not exactly clear about steering is this:
>> I find that sticking my knee out when going round a tight corner
>> enables me to adjust the radius of the turn by bringing it in . Is it
>> just me?
>
>
> Nope - assuming you mean the knee on the inside of the corner. Sticking
> it out means you can corner sharper/faster, bringing it in will relax
> the corner. The only problem I find is that my SPDs unclip :-(
>
yes, that's exactly what I mean. I've got a sort of feeling about how it
works, I think that it's about moving your centre of gravity so that you
need to turn more sharply, but I'm not quite sure abut how the reaction
forces on the rest of your body work out yet.
Roger thorpe

 

[Rob Morley]

In article <[email protected]>, Ian Smith
[email protected] says...

> How do the 'you can only turn by shoving the bars the wrong way' and
> 'leaning a bike won't make it turn' lot explain the ability to ride
> no-hands in other than straight lines?
>
When you lean the bike to one side by bending at the waist, the inertia
of the front end leaves it pointing in the other direction -
countersteer. The caster action then re-estsblishes equilibrium and you
turn.

 

[Roger Thorpe]

Pete Biggs wrote:

> Ian Smith wrote:
>
>
>>How do the 'you can only turn by shoving the bars the wrong way' and
>>'leaning a bike won't make it turn' lot explain the ability to ride
>>no-hands in other than straight lines?
>
>
> They don't say you shove the bars, they say you lean your body in such a way
> at such a time that will make the wheel twitch right when you want to turn
> left. Or something like that.
>
> Try the puddle test no-handed.
>
> ~PB
>
>
I thought that we just had all this - and that I missed it...
so here's my tuppenceworth.
IMO
Castor is important for a bike, and it's not caused by drag, so much as
lean. This means that when you lean the bike to the left then the front
wheel steers to the left. This is what is going on when you ride with no
hands. If you don't believe me(and why should you?) then try riding with
no hands on the bars and no feet on the pedals. It's also what you're
doing when you push the bike from the saddle.
There are two things that I ought to do now. One is to read Arcihbald
Sharp (it's still in print you know, try abebooks.com). And the other is
to try the puddle test with the bike being pushed by the saddle. If I'm
right then there would be no countersteering evident in that case.
(this would, of course make non-countersteering tracks easily forgeable)
Has anyone tried this or do I really have to go out in the rain?

The covincing evidence for counter steering (for me) is to do the
experiment, but only push the handlebars with one finger. The turn
starts so quickly that the bars seem to move in the opposite direction
to the push.

Roger Thorpe

 

[Ben C]

On 2007-02-23, Roger Thorpe <[email protected]> wrote:
> Pete Biggs wrote:
>
>> Ian Smith wrote:
>>
>>
>>>How do the 'you can only turn by shoving the bars the wrong way' and
>>>'leaning a bike won't make it turn' lot explain the ability to ride
>>>no-hands in other than straight lines?
>>
>>
>> They don't say you shove the bars, they say you lean your body in such a way
>> at such a time that will make the wheel twitch right when you want to turn
>> left. Or something like that.
>>
>> Try the puddle test no-handed.
>>
>> ~PB
>>
>>
> I thought that we just had all this - and that I missed it...
> so here's my tuppenceworth.
> IMO
> Castor is important for a bike

Why is a brownish unctuous substance with a strong penetrating odour
secreted by certain glands in the groin of the beaver important for a
bike? Should I put it on my chain?

> , and it's not caused by drag, so much as lean. This means that when
> you lean the bike to the left then the front wheel steers to the left.

Yes, and I think this is basically how bikes work. If it leans left, it
steers left, and that makes it tip right again since the mass is thrown
to the outside of the turn. Those are the ingredients of its stability.
How do you steer? You just don't let it tip all the way up again.

I don't understand Jobst Brandt's theory for why countersteer is
necessary, although he may be right. I don't see why you can't lean the
bike over to initiate the turn just by shifting your centre of mass.

The puddle test sounds hard to do, since the front wheel weaves about a
bit all the time as part of the process of staying upright. It seems it
would be hard to separate the countersteer from the noise.

 

[Mark Thompson]

> I don't understand Jobst Brandt's theory for why countersteer is
> necessary, although he may be right. I don't see why you can't lean the
> bike over to initiate the turn just by shifting your centre of mass.

It's 'cos the bike is countersteering all the time (well, not ALL the time,
but you know what I mean), and because it's so effortless to do, the rider
always uses it to get the lean necessary for the turn.

Leaning the bike through shifting your body mass will prolly just produce
countersteer, unless you hold the bars steady. With the bars held steady,
one would have to do some pretty extreme (by normal standards of cycling)
moves to shift the centre of gravity.

This lot thing that whatever you do you can't shift the centre of gravity
without countersteer. They may be right, but I'm not about to buggr up my
Trek 5000 trying. Anyone got a hack bike?

 

[Rob Morley]

In article <[email protected]>, Ben C
[email protected] says...
<snip>
> I don't understand Jobst Brandt's theory for why countersteer is
> necessary, although he may be right. I don't see why you can't lean the
> bike over to initiate the turn just by shifting your centre of mass.
>
Because you don't have anything to push against to shift your centre of
mass.

 

[Rob Morley]

In article <[email protected]>, Roger Thorpe
[email protected] says...
<snip>
> This force acts at the contact with the road and, since this force does
> not act through the centre of gravity it produces a moment

Mmm, Cheese Moments

 

[Alan Holmes]

"Pete Biggs" <[email protected]> wrote in
message news:[email protected]...
> Ian Smith wrote:
>>>
>>> http://www.sheldonbrown.com/brandt/descending.html :
>>> "What is not apparent, is that two wheeled vehicles can be
>>> controlled ONLY by countersteer, there is no other way.
>>
>> Which means, presumably, that it's completely impossible for me to
>> steer while riding no-handed.
>>
>> OK, as long as no-one tells my bike, I'll just carry on doing it and
>> we'll be fine.
>>
>> How do the 'you can only turn by shoving the bars the wrong way' and
>> 'leaning a bike won't make it turn' lot explain the ability to ride
>> no-hands in other than straight lines?
>
> You steer by moving your body, whether you have your hands on the bars or
> not.

Correct, you lean the way you want the bike to go.

>
> ~PB
>

 

[Ben C]

On 2007-02-23, Rob Morley <[email protected]> wrote:
> In article <[email protected]>, Ben C
> [email protected] says...
><snip>
>> I don't understand Jobst Brandt's theory for why countersteer is
>> necessary, although he may be right. I don't see why you can't lean the
>> bike over to initiate the turn just by shifting your centre of mass.
>>
> Because you don't have anything to push against to shift your centre of
> mass.

You can move your centre of mass relative to the bicycle though, with
the result that its projection vertically down onto the ground becomes
offset from the tyre contacts, and you fall over.

If you're sitting balanced on a stationary bike it's easy to fall over.
You could just push your arms out to one side for example. You push your
arms one way and your body gets pushed back a bit the other way. The
centre of mass of rider + bike does not initially move relative to the
Newtonian Reference Frame, true, but it does move relative to the wheel
contacts, and so gravity tips you over.

If the stationary bike is in outer space, whatever flailing around you
may do (short of e.g. removing your h****t and hurling it into the void)
will not move your COM. But on Planet Earth you do have an external
force-- gravity, acting through the tyre contacts.

Even throwing your helmet away in a sense doesn't move the COM of rider
+ bike + helmet. But it might get you back to your spaceship at the
expense of never seeing your h****t again.

 

[Rob Morley]

In article <[email protected]>, Ben C
[email protected] says...
> On 2007-02-23, Rob Morley <[email protected]> wrote:
> > In article <[email protected]>, Ben C
> > [email protected] says...
> ><snip>
> >> I don't understand Jobst Brandt's theory for why countersteer is
> >> necessary, although he may be right. I don't see why you can't lean the
> >> bike over to initiate the turn just by shifting your centre of mass.
> >>
> > Because you don't have anything to push against to shift your centre of
> > mass.
>
> You can move your centre of mass relative to the bicycle though, with
> the result that its projection vertically down onto the ground becomes
> offset from the tyre contacts, and you fall over.
>
> If you're sitting balanced on a stationary bike it's easy to fall over.
> You could just push your arms out to one side for example. You push your
> arms one way and your body gets pushed back a bit the other way. The
> centre of mass of rider + bike does not initially move relative to the
> Newtonian Reference Frame, true, but it does move relative to the wheel
> contacts, and so gravity tips you over.
>
> If the stationary bike is in outer space, whatever flailing around you
> may do (short of e.g. removing your h****t and hurling it into the void)
> will not move your COM. But on Planet Earth you do have an external
> force-- gravity, acting through the tyre contacts.
>
But gravity only acts vertically, and we're talking about a horizontal
force.

 

[Tony B]

Pete Biggs wrote:

> They don't say you shove the bars, they say you lean your body in such a way
> at such a time that will make the wheel twitch right when you want to turn
> left. Or something like that.


That's what was happening in the school yard, when I pushed the bike
away from me. The geometry of the front end of the bike forces the wheel
to whip left as I push right... immediately after this, the front end
flops over to the left and the bike goes into a left hand arc.

Tony B

 

[Pete Biggs]

Ben C wrote:

> The puddle test sounds hard to do, since the front wheel weaves about
> a bit all the time as part of the process of staying upright. It seems
> it would be hard to separate the countersteer from the noise.

It's easy. Ride the bike normally through a puddle at 12 mph, then turn.
Repeat 10 times. If it was just noise, you'd only see what looked like
evidence of countersteer about 5 times. I bet you'll see it 10 times.

~PB