Just pause the movie and use the left and right arrow keys to advance and rewind frame by frame.
As a motorcycle rider, I will have to agree with everyone that countersteering is how you maneuver the bike. Go here for a good discussion about it, with a nice pic about halfway down the page:
And if you don’t feel like reading the whole thread, at the top of the second page are some links to short, slo-mo videos of countersteering in action:
That’s the best one, I think. Also, trabi’s clip makes it pretty obvious, IMO.
Here is a good description of motorcycle countersteering, sailor. Any decent Motorcycle Riders Safety Course will teach it. It is a fact. It is a fact you have not yet been made aware of, but a fact nonetheless. You are never too old to learn something.
I can accept counter steering exists and that it is effective. But I can’t believe it is the ONLY way to steer a bike.
Are you telling me that if I rigged a bike so the wheel could only pivot left it would be impossible to turn left?
Brian
It would also be impossible to turn right…
Or even balance. When moving at low speed, you keep your balance by making minute corrections with the handlebars - to correct a fall to the left, you nudge the bars to the left etc.
What happens to a beginner cyclist who’s about to lose balance? The front wheel starts to wobble from side to side as they overcompensate and over-overcompensate etc. until the wheel tucks under and they fall off. Even going in a straight line, if your handlebars only moved to the right you would fall over to the left within a few feet of setting off.
It’s possible to turn without a visible and/or deliberate countersteer motion. Balancing a bike requires constant corrections to keep the contact patch directly under the center of mass. If you changed the pattern of this repetitive correction slightly, you can let the contact patch drift to one side. It accomplishes the same thing as countersteering, but it won’t look or feel like it. It’s also slower than a deliberate countersteer.
It is NOT the only way to steer, but it is the BEST way to steer quickly at higher speeds. You swerve faster at highway speeds by doing this. Under 30mph it is not generally as effective or needed on a motorcycle, from what I have been taught.
The Cecil column: http://www.straightdope.com/mailbag/mangularmo.html
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Actually the gyroscopic forces are not that significant on a bicycle. (I don’t have any motorcycle experience, but I belive it is different)
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Sorry but this is wrong.
As a test of this, take bicycle wheel hold it by one axle end and spin the wheel, then try to turn the wheel in any direction other than along the plane of rotation.
You will experience a force that tries to twist the wheel in another direction, in fact this is always in a plane at right angles to the force you are putting in.
This is a basic law of precession, and is the principle behind gyrocompasses.
Signicant values in the equation are speed of rotation, mass being rotated, radius of mass being rotated,force disturbing the steady rotational state, and angle of force.
Just spinning the wheel at a moderate speed, will produce a signifiacnt force, and when actually riding along the wheel would usually be rotating much faster.
This is a good thing as this rotation along the line of the rim produces a force which directly opposes any sideways tilt, and this keeps you upright.
This is one serious reason why racing wheels make a bike seem so much more twitchy, the race wheels are light and do not produce as great a stabilising force as ordinary rims would.
Countersteering is the only way a lean can be initiated, once the machine is in a turn differant forces come into play, balancing each other out.
You can actually lean your bodyweight, but this is much slower than counter, and in any case still ends up with countersteering, but not it does not appear as obvious.
The OP asks a somewhat differant question anyway.
>> You are never too old to learn something
I always was precocious. By age 12 I was too old to learn many things and by age 16 I was a full-fledged dirty-old man.
Many of those pages rely on the gyroscopic effect keeping the bike up which has been debunked but is still repeated over and over. Just because something is widespread belief does not make it the truth.
I am not going to get into a deep discussion here because nobody is going to convince anybody. I have already stated what i will consider sufficient proof: slo-mo video of a bike from staright ahead where you can clearly see that the wheel turns in the opposite direction of the turn. This is not difficult to get and should settle the question. In the meanwhile I remain unconvinced.
Countersteering only comes into play above about 5mph.
UncleBill, what other way is there to steer at a high speed?
I figure we may as well continue the countersteering debate since the thread has been bastardized so badly as to be unrecognizable.
Sailor:
Take a look at trabi’s post a bit earlier. Also to be found here:
http://www.vsa.cape.com/~wayg/mrep/csteer.htm
and the video here:
http://www.vsa.cape.com/~wayg/mrep/pics/csteer.mpg
Pause the movie and use your left and right arrow keys to step the movie frame by frame.
You can steer slowly at higher speed with normal push-right-go-right. You eventually go right. Not good to avoid sudden problems.
You can just lean your body without holding handlebars (not something I recommend or do).
That’s a staff report and contains many mistakes. The follow-up is much better and has a good link to the experiments carried out with non-gyroscopic wheels.
here is a PDF document which elaborates on the forces involved.
In my experience, the slight counter steer used in high spped turns is there to balance the initial lean into the corner. My physics is a bit rusty, but aren’t the forces used while leaning the bike over greater than those involved when the bike is at the correct angle of dangle?
UncleBill
“Push right go right” is counter steering. And the whole body leaning is very very slow and also ultimatly due to countersteering.
BTW I think someone said it already but countersteering initiates the turn but once the bike leans the wheel follows the direction of the turn.
I don’t know if this is the point that is disturbing sailor; it is pretty obvious that a bike cannot continue on a left-turn track with the wheel turned right without skidding.
Can you please cite a debunker?
I don’t know about gyroscopics keeping it up in steady state, but I know for absolute sure what happens when a spinning wheel turns from General Physics I.
You are correct, my mistake. Better made sitting at a desk than at 65 mph on two wheels. I meant to say push-left-go-right. It is a much less efficient way to turn at speeds higher than 5 mph, becoming less so the faster you go. The lean is the important part, countersteering is the fastest way to get there.
The American Journal of Physics has a paper published therein covering just this subject. (Warning, PDF) Sorry, sailor, no slow-mo-video in the AJP.