Counter Steering

Here is the real scoop on countersteering: http://www.2wf.com/articles/stories/AB44B4F1-B8AF-440C-911D-3B3744371990.asp

Here is a good article on "Counter Steering" by James R. Davis, http://msgroup.org/TIP048.html

A motorcycle's dynamic stability is based on the rider's motor reflexes interacting with the vehicle's steering geometry. Loop gain comes from the forward motion. Intellectual understanding of the process is not required as illustrated by the disagreements between still living riders.

This is a term from Motorcycling, but applies to normal bicycles as well. At all speeds above walking speed, cycles turn by leaning. At low speeds you can turn the front wheel in the direction you want to go, but this fails at higher speeds.

CounterSteering is the technique you use to induce the lean which enables you to track around a corner. It sounds confusing - you push forward on your right handlebar to turn right. Essentially, you're turning the wheel slightly in the direction opposite of the way you want to go - hence 'counter' steering. The way I heard it originally explained is that this then 'trips' the cycle and it leans towards the right. The harder you push the faster it leans over, so be very careful when first practicing this technique.

After learning this technique back around 1980 I had the thought that I finally knew why it is so hard to learn to ride a bicycle. Until your body learns how to do this CounterSteering, without being told about it, all you can do is wobble all over the place in one continual series of overcorrections. But once your body subconsciously learns this, a real case of TacitKnowledge if there ever was one, cycling is completely natural and impossible to forget.

The best part of this practice however is that even though everyone does it, it is so counter-intuitive that experienced cyclists will swear that is not the way it works. Even worse than BodyFollowsEyes in this respect. -- PeteMcBreen

I think the effect is due to the rotational momentum of the wheel. When you try to angle the wheel, this changes its rotational momentum and the difference is shifted to the rest of the bike. The wheel exerts a force on the bike so that when you get out of a turn, the wheel lifts the entire bike upwards.

Edit comment: it has nothing (well very little) to do with the angular momentum (gyroscopic effect of the turning wheel). It is caused by the momentum of the bike and rider tipping the bike over as it tries to change direction. The same effect would happen if there were no wheels. Angular momentum applies some force, but it is probably less than 100th of force of momentum.

I remember a great demonstration of the effect at the Ontario Science Centre. You stood on this platform/wheel and you held a spinning bike wheel in your outstretched hands. Then, when you tilted the bike wheel to the left or right, your entire body would spin. It had nothing to do with air resistance or anything of that nature, just a shift in momentum, and that's what made the exhibit so difficult to understand.

Tripping the bike sounds like it would be extremely dangerous and hard to control. -- RichardKulisz

Well, mostly right. When you push-steer a motorcycle from vertical (ie going straight ahead) you are causing it to pivot around its vertical center of mass. If you push right, the bottom of the bike goes right (as that is where you've told the front wheel to point), the pivot stays where it is, and the top goes left. So at least momentarily, the bike is going to the right a bit. The reason that the bike ultimately turns left is that the contact patches on the edge of the tires (which you are rotating onto the pavement) are closer together than the contact patches at the center of the tires. What this means is that the more angle you give the bike, the smaller a circle it describes, and the more you turn. The mechanics are slightly different once the bike is already in a turn, but the differences aren't really significant because the result is the same: you push left, you turn left.

I've got to disagree here. The reason the bike ultimately turns left is because the wheel ends up pointing that way, the lean is needed to stop the bike falling to the right. At a given speed, a tighter turn needs more lean than a wider turn. If you just turn the handle bars and don't allow the bike to lean, it will fall over.

The sequence is.

Tune bars right, bike starts falling to left, turn bars left just far enough and quick enough to leave the bike in a new equilibrium and a curved course, leaning over. -- AndyMorris

I'm not so sure. I remember in physics class we were given the axle of a spinning bicycle wheel. It behaved most oddly, since any attempt to change the direction of the axle would result in the wheel trying to turn the person. It's a basic result of the conservation of angular momentum. I think the problem is more complex on a bike, but is still derived from the same fundamental law. No "starts falling", no equilibria. -- TaralDragon

I was disagreeing with the bit about the contact patches, your right in saying that the gyroscopic effect helps, when you turn the wheel right the gyroscopic effect helps to tip it over to the left, so does the fact that the bottom of the front wheel is moving to the right. Someone did an experiment with a bike with a counter rotating extra front wheel, it was ridable but strange.

Experiments with a rear wheel steered bicycle have always produced unridable bikes. With a conventional bike, if you feel the bike is falling to the left, you steer to the left, this both puts the front wheel under the bike and starts a curve that will tend to correct the lean. With a rear steered bike these effects are opposite, a steer to the left will move the rear wheel further out from under the bike, before the turn starts to correct the lean.

Wasn't clear enough about the contact patches. When you lean the bike over, the contact patches change shape because of the curvature of the tire. In a left turn, the top part (leftmost part) of the contact patches are somewhat closer together than the bottom part. This is why you turn. A similar situation, which is easier to visualize, is an ice-cream cone lying on its side. Even if you push it straight, it will still roll in a circle because one end is smaller than the other.

Got to really disagree with you there, what would happen is you used very thin hard steel tyre, would you have to lean over further?

The Turn is produced by the direction the front wheel points not by leaning, you have to lean to stop yourself falling over away from the turn, that's why the faster you go round a corner the more you have to lean.

Gonna go against some currents here and claim that counter-steering and gentle leaning do the same thing - they move the center of mass of the rider/bike pair off of the line connecting the two wheels' contact points with the road. To maintain equilibrium and not fall, you need to add a sideways force. In this case, the force is the centrifugal force acting in the direction toward the outside of the curve you are making to keep from falling. Counter-steering works faster because it quickly moves the front wheel out from under the center of mass - your fast lean into the turn then moves the center of mass back into equilibrium. A gentle lean is harder to do. Try it and you'll feel like you are balancing - exactly the hint needed to see it is all about moving the center of mass around. The importance of these sideways forces was made real graphic to me one day when I suddenly encountered some slick black ice and the bike slid out sideways from underneath me. Glad I had a helmet, but still ended up with stitches. I think if gyroscopic forces were key, bikes on ice would not fall over so easily and unicycles would work better.

I was taught CounterSteering as a turning technique as being different from normal turning. That is, it's an alternative "trick" turn. It's true that at higher speeds you turn by leaning, but that lean is induced more easily by actually leaning the body. This can be accomplished even when riding in Look No Hands mode.

CounterSteering however is an alternative trick turn, more suited for a rapid lane change than graceful cornering. As taught to me, it worked like this: if I want to move to the left, give a sharp hard whack to the left handbar, forcing it forward. The front tire will then catch and react, with the result that the bike jumps to the left.

It is an extreme technique, and it can tear great bites out of your rubber, and if not done right the "trip" ends your "trip", so to speak. It is however very good for rapid lane changing, so keep it in reserve for those emergencies where you don't want to go whamming into whatever happens to be directly in front of you.

Analogous to flying would be the immelman turn - a deliberate stall, a moment of total instability, chaos captured like poetry, and bingo you're off in a completely different direction. -- EricScheid

Countersteering isn't a trick technique. It's the safest way to steer a motorcycle. It doesn't make the bike jump and it doesn't rip anything out of your tires. Trying to turn your bike by leaning it is very dangerous. Bikes aren't responsive to that type of input. The wheels, at any speed above walking, are turning very quickly and act as gyroscopes. They keep the bike upright. The faster you ride, the more stable the bike becomes because of this gyroscopic force at the wheels. This force is so strong that you can't reliably lean the bike by weight-shifting. Many single-vehicle accidents occur because people don't know how to push steer.

Push steering is doubly important with a passenger on the bike. If you are steering by leaning, then you are effectively relinquishing control over your bike to your passenger, as they have 50% of the steering control. If you push steer, though, it doesn't matter where the passenger leans. The bike goes where you tell it to.

If you have doubts, you should contact Penguin Racing School (or any certified racing or safety school) and ask to talk to a qualified instructor. You can also read about this in "Twist of the Wrist" by Keith Code. Actually, this book should be required reading for anyone riding a bike.

I think perhaps we are talking about two different things then, which unfortunately have the same name. There is a steering technique which is drastic, which does cause the bike to jump, and which does chew chunks of rubber. This was termed "counter steering" by my instructors. Perhaps you know the technique by another name, or perhaps you're not familiar with it. It's a technique which certainly works, but is not a technique to teach beginners, it's an advanced technique.

(Not the previous italic poster) We're talking different degrees of the same thing. If you replace "sharp whack" in your description with "gently pressure", you've got the standard technique that numerous books and articles describe. I have no doubt that a sharp whack would make the bike jump, but that's not what most people are talking about when they use the term "countersteering".

You do illustrate the point others on this page have been trying to make. You can vary the tightness or quickness of a turn by varying the extremity of the handlebar inputs. And handlebar inputs can be much more finely and reliably controlled than weight-shifting.

Sounds like landing a plane (as I understand it): you use the throttle & spoilers to control your descent, and the elevator to control your speed, even though you know that it's the elevator that controls your up and down motion. On a bicycle, you steer by leaning and lean by steering.

Actually, is it not easier to talk about counter-steering in the context of exiting a turn? Your bike is tilted because you are turning - to get out of the turn, you cut the steering tighter into the turn, which throws you up into a vertical position.

An analogous technique:

You are first at a stoplight, and your lane merges with the adjacent one up ahead. You don't want to go through the hassle of racing the car beside you to be the first one through the light.

Therefore, when the light turns green, floor it - but only for a second. The car beside you will see you are racing, and will feel compelled to race as well. When you let off, you have plenty of room to merge behind the other car.

My father taught me this trick when I first learned to drive, but it has been years since I have used it. Getting too impatient in my old age, I guess....

Weird: I used to do CounterSteering in a motorcycle racing game. I figured it was just a bug. Now I realize the physics was accurate, and my understanding was buggy.

I use to ride motorcycles with a couple of other electrical engineers and we had long conversations that sounded just like this page. They were often followed by long rides on country roads where theories could be explored. One thing is for sure: at high speed the actual motions you make are too small to see. I had better luck paying attention to my hand pressure on the grips. Eventually I reduced this to hands-free riding where in I could initiate turns with one finger pressing on the grip in the counter motion described above (push right grip forward to turn right.)

I've been told that this works for the same reason an ice cream cone will roll around in circles, the motorcycle turns around the point on the ground where the wheel's axis intersects. At high speed one's turning radius is large, even with fast lane changes, so of course grip motions are small. This theory of steering is supported by realizing that it is easy to steer no-handed by leaning alone. The theory doesn't explain why I can drive straight while leaning. -- WardCunningham

In big ships...

I'm not an engineer, and I can't even remember where I read this. But it sticks clearly in my brain that the way large ships generate the force needed to to push the massive rudder to STARBOARD is by having a little flap in the rudder that pokes out towards PORT. This is sort of like CounterCounterSteering?, I suppose - to steer the ship to starboard the rudder also must turn towards starboard, but in order to make that happen a little piece of the rudder first points to port.

Back before fly-by-wire, when an aircraft's controls were mechanically linked directly to the control surfaces, this same arrangement was used to drive large rudders on big planes.

A friend of mine and I were recently riding our bikes and stopped for a break. During the ensuing conversation he mentioned couterstearing. He described the technic. I couldn't wait to get back on the bikes so i could give it a try. What a wonderful technic! I have ridden motorcycles for years and never heard of this before. So I got online and found this page. I read it in its entirety and found it to be too technical and complex for me. But in simple terms, this is how I believe it works. At speed your motorcycle is balanced with the center of the tire in contact with the road surface. When you "push" your left handlebar grip slightly forward this causes your front tire to rotate ever so slightly to the left. When this happens the road contact point with your front tire shifts slightly to the outside (right side) of your front tire. Since your steering tire (front) is now making contact with the road with the right side of the tire, it puts you into a very slight right hand lean with in turn starts your bike into a right hand turn. It works great. Use very little pressure. I like the term used earlier on this page of "inducing" the lean. The way that motorcycle tires are shaped, there is a center portion that flattens with the weight of the bike (and you). When riding in a straight line in an upright postion this flattened portion is the only thing touching the roadway. It is probably only a few inches wide, depending on the side of your tire and the weight exerted on it. In order to turn at speed, you must get off of that flat surface and use the outer portion of the treaded surface of your tire (not the side of the tire) I have notice from time to time that I can sort of get caught with the wrong portion of the tire surface in contact with the roadway resulting in a very awkward turn. I think this happens because I didn't know about this counterstearing phenomina. I was trying to make, say, a left turn and was forcing it a bit by trying to turn the handlebars slightly toward the turn. What was happening then was I was forcing the front wheel to shift ist contact point with the pavement towards the right side. So the bike was getting opposite forces. I was leaning left for a left turn but forcing the bike to use the right bottom portion of it surface which made the bike want to go right. As I say,,, very awkward. I should add that these were normally medium speed (35 mile per hour) curves. So now that I understand the use of the counterstear method, I can use it to my benefit and avoid using it to my detriment. Good luck and safe riding to all.