Countersteering

 

As promised and anticipated.

I wrote:

to which BGJ replied:

Before i actually go out and practice anything like that on
my more-than-a-quarters-salary-before-taxes worth bike,
i'd appreciate if you (or elsebody) could elaborate on the
subject. Now, please, do not take it as a joke or playing
dum - it's only a matter of extreme caution.

What _EXACTLY_ do you mean by "push left" and "push
right"? Pushing the bar to left or right is not possible
since it's fixed to the forks.

I do understand you mean _ROTATION_ of some kind.
Now, suppose you wish to go left. How do you pull/push
the bar with the left hand? Right hand? How do you lean
(if at all) on the bike?

--
Vänligen
Konrad
---------------------------------------------------

Sleep - thing used by ineffective people
            as a substitute for coffee

Ambition - a poor excuse for not having
                 enough sence to be lazy
---------------------------------------------------

 

Konrad Viltersten wrote:


This countersteering model I am describing also describes gyroscopic
precession.

Point your left index finger toward your monitor. That represents the roll
axis of your motorcycle.

Point your left middle finger to the right. That's your handle bar.

Point your left thumb up. That's the steering axis of the motorcycle.

Push your left middle finger firmly toward the monitor.

Notice what happens to your left index finger. It points to a little to the
left, representing out tracking of the front wheel.

But look what happens to your wrist and forearm. It twists to the right. But
your wrist joint doesn't bend.

In this model, your wrist and forearm are analogous to the chassis of your
motorcycle.

You've pushed the right side "handlebar" forward to get your chassis to lean
right.

That's countersteering.

In the real world, the yaw axis of your motorcycle never deviates ("out
tracks")
so far, because the front tire contact patch has to react against the
pavement
gripping the compliant rubber..

If you want to quickly roll your chassis into a left lean angle, push as hard
as you dare against the left handlebar.

However, you should know that the original equipment tires on your Varadero
don't have a lot of grip. Road racers on their race bikes have so much grip
they sometimes strain a shoulder muscle from pushing so hard against the grip
to get the motorcycle down to the desired lean angle.

Then they countersteer the machine back to vertical with another hard push
when they are done with the turn.

Each maximum effort push saves a second or a fraction of a second in the turn.


Newbie road racers are cautious in countersteering down to maximum lean angle.
They may take three of four seconds to get down to maximum lean angle because
they don't trust the grip of their tires.

And, as I said above, your Varadero tires won't have a lot of grip on the
road.

 How do you lean

Leaning doesn't turn the motorcycle very much. Experienced riders will hang
their body off a little bit to one side so the motorcycle itself is closer to
the vertical than it would be if a line drawn through the rider's center of
mass and the motorcycle's center of mass aligned perfectly with the tires'
contact patches.

--
Message posted via MotorcycleKB.com
http://www.motorcyclekb.com/Uwe/Forums.aspx/bike/200709/1

 



It's very simple. Ignore everything about gyroscopic precession; it's
complicated and its contribution to steering force is negligible.

To turn right, first look in the direction you want to go, then with
your right hand, push on the right handle bar. (You're turning the
steering to the left.) Inertia will make the motorcycle want to continue
straight ahead, but the left-steering will make the tire patch go to the
left. As a result, the bike leans to the right. Now since your
motorcycle's tires are round in cross-section, not rectangular like a
car's, the bike will steer to the right.

Since you are actually steering the handle bar to the left but the bike
goes right, this is called countersteering. It is the most efficient way
to get the bike to lean and go in the direction you want.

While you are in the turn, do not let off the gas! The most important
skill for motorcycling is to gauge at what speed to enter a turn, how
much to lean, and how much to accelerate out of it. This comes with
practice.

Forget everything about gyroscopic forces; they're too complicated and
not important. Ignore anyone who says to only use countersteering in an
emergency; they're just wrong. Countersteering is the correct way to
steer the motorcycle.

--
Timberwoof <me at timberwoof dot com>
faq:  http://www.timberwoof.com/motorcycle/faq.shtml
It's easy to say a war is so important your neighbor should go fight it for you.

 

Timberwoof wrote:


Where did I say that gyroscopic precession contributed to steering force?

The left hand model that I described *works* the same way as gyroscopic
precession. You input a force in one plane, you get an output in another
plane,
and the gyroscope of the front wheel doesn't work against countersteering.

--
Message posted via MotorcycleKB.com
http://www.motorcyclekb.com/Uwe/Forums.aspx/bike/200709/1

 



Where did I refer to you?


I think you introduce an unnecessary concept and thus needlessly
complificate the material.

--
Timberwoof <me at timberwoof dot com>
faq:  http://www.timberwoof.com/motorcycle/faq.shtml
It's easy to say a war is so important your neighbor should go fight it for you.