Created by IanJ
What is countersteering anyway?
This is such a common question, and one which raises so much contentious argument, that it seemed worth offering my well-reasoned opinion on the subject. Of course, it is all just opinion, as I haven't performed the repeatable experiments necessary to prove what I'm about to write. Note that this article is equally applicable to motorcycles or bicycles, although it's harder to be conscious of countersteering a bicycle due to its relatively light weight.
That said, here's the basic idea of countersteering, on anything with two wheels: when you're going in a straight line, the handlebars are centered; when you want to turn, you actually have to turn the handlebars in the wrong direction first, to lean the bike over, then you steer into the turn to keep the bike from flopping completely over. The part where you steer in the wrong direction to make the bike lean over is called "countersteering."
Why is countersteering important? Because it's the only way to turn a moving, two-wheeled vehicle. If you're doing it unconsciously, by thinking "steer left" or shifting your weight, or putting more pressure on one peg/pedal or the other, that's not very efficient. If you do it consciously, you can steer your bike with amazing speed and accuracy, which could very easily save your life one day.
Kids on bicycles
Most people who ride motorcycles also learned to ride bicycles at some point in their lives. Some of you may have also more recently taught a child how to ride a bike. Learning how to ride a bike is really hard! You probably spent some time with training wheels on your bike, leaning hard into them going around corners.
The human mind doesn't readily encompass the idea of turning the wrong way in order to go the right way. When you were a kid, and wanted to turn right, you swung the bars over to the right, exactly as is sensible. Only, when you did that (keep in mind, you were going at a low speed), the bike fell over to the left, hopefully onto the training wheels.
We all called it "learning to balance" when I was learning to ride a bike. I thought of it as gaining some kind of magical sense of balance, as if my natural ability to stand upright was somehow discarded once I got on a bike. You may see where this is going. Of course, I still knew how to balance, but I didn't know how to countersteer. Most dads don't know that that's what they need to teach, but that's exactly what a kid has to learn to ride his bicycle.
Without learning the counterintuitive act of steering in the wrong direction, no one can figure out how to ride a bicycle. That's the magic switch that goes off in your brain, and suddenly allows you to ride the bike. I bet if you think back, you probably spent some time swerving your handlebars back and forth, marvelling at the weird feeling of turning contrary to which way the front wheel was pointing.
Steering while moving
When your bike is moving, there are a couple of factors keeping it upright and running in a straight line. The front end's trail (which is the distance between the steering pivot point and where the wheel actually hits the ground) provides a castering force, like the wheels on a rolling office chair. The rotating wheels are big gyroscopes -- just like a child's toy gyroscope, they will try to stay upright (and thus not steer in any direction other than straight). If you started your motorcycle or bike rolling on a straight road without a rider, it wouldn't fall over until it ran out of speed or hit something.
When the bike slows down enough to fall over, that's because the lower the speed, the less force both trail and the gyroscopic forces exert. At some speed, the not-precisely-balanced weight of the bike overcomes the amount of force exerted by the trail and gyro forces, and gravity wins.
In order to make the bike turn, you have to unbalance it. The only way to unbalance a bike at speed is through countersteering. No matter how far you lean off the bike, it's not going to change direction: the forces keeping it upright are too strong. [Update: this statement is incorrect -- I've steered my Ninja by leaning off without handlebar input, but it's really slow to react. The principle, especially for beginners, is still sound, though.] However, if you turn the handlebars in one direction or another, the bike immediately unbalances away from the direction you turned. Centrifugal force pulls the bike sideways, and since the tires are "stuck" to the ground, the bike naturally pivots around them, to lean over away from the turn. Once you've achieved the lean angle you desire, you turn the handlebars back in the direction of the turn to prevent the bike from flopping completely over onto its side. This process of steering away from the turn then into it usually happens so fast that by the time you notice what's up, you're steering into the turn, and thinking I'm a crazy man.
However, next time you're travelling at speed (over about 30 MPH on a motorcycle, or as fast as you can get going on a bicycle) and traffic around you is very sparse -- ideally on a completely deserted road -- try pushing on one side of the handlebars. Just a slight and even pressure on one side. The bike will immediately start leaning toward the side you were pushing on. Now, try pushing on the other side. The bike stands right back up. That's the essence of countersteering.
Now, this is the part where many people call "bullfeathers!" on the whole countersteering thing. Most experts explain countersteering as if it were the only thing in the world you needed to know about steering a bike. It's not. You use countersteering to lean over, and then, most of the time, you steer into the turn! Countersteering is mostly useful for getting you leaned over, a great deal of the time. (Note that at high enough speeds, you actually countersteer all the way through a turn, because the higher the speed, the stronger those upright-pulling forces are. But that's a different thing, I'm writing for street riders, not racers; go away kid, you bother me.)
All of this applies to low-speed steering as well, all the way down to a dead stop (but see below for the "dead stop" discussion). If you're rolling at all, the only way to steer a bike is to get it leaned over in the direction you want to turn, at least a little tiny bit, or when you turn, the centrifugal force will flop the bike over to the outside of the turn.
So, to cause the bike to lean in the direction you want to go, you have two choices at low enough speeds (like, below about 7 MPH on a motorcycle): you can countersteer, or you can lean your body weight to the side you want. Leaning yourself over works at this point because the force of gravity acting on your body is stronger than the upright-pulling forces described above (remember that they get stronger as speed increases, so they get weaker as you go slower).
Countersteering also works all the way down to a complete stop. You can practice by finding a big empty parking lot again: get the bike rolling in first gear, and let the engine settle down to idle speed (hopefully your parking lot is flat). Carefully take your weight entirely off the handlebars, and push gently on one side. Whichever side you push on, the bike will immediately lean toward it. Go as slow as you can, and try it (but don't push very hard). Countersteering still works.
I think the reason many people claim countersteering "starts" around 10 MPH is that they can make the bike turn without using countersteering below that speed. While it's true that you don't need countersteering to steer while going slowly, you can still use it.
Steering from a stop (U-turns)
If you're sitting stopped somewhere, and want to make a quick U-turn, you're not going to use countersteering. The whole point of countersteering is to take the bike from being perfectly vertical, to being leaned over. When you're sitting on the bike, stopped, you can use your leg muscles to lean the bike over, before you start going. Then, once you're moving, you steer into the turn, just like you'd expect.
So, countersteering doesn't have any meaning from a stop, you only want to use it once you're rolling.
A little thought experiment
And finally, for the Doubters among you, I propose a thought experiment (note: I don't recommend trying this for real, because it will probably break your bike and might break you).
Imagine that you're sitting on your bike, stopped. I walk up and say "ooga booga!" and put a magic spell on your bike (thought experiment, remember), so that you cannot turn the handlebars to the right, past the center point. You have full movement of the bars from center to the left lock, but when you hit center, the bars absolutely won't move any further.
Now, imagine holding the bike straight upright, no leaning to the left. Start it moving, with you on board. You cannot turn the handlebars to the right at all. Really put yourself mentally on this vehicle, with the steering "broken" as I describe.
How long do you last, going as slow as you can, before the bike flops over onto its right side? Does even thinking about this make your body get squirmy and uncomfortable? It does for me -- my body knows from riding bicycles and motorcycles that if something happened and my steering got locked in the manner I just described, I'm screwed. I'll be falling over to the right so fast, I'll be lucky to escape without a broken leg, no matter how hard I lean my body to the left once I'm going.
Now, imagine the same thing, but you're going at high speed (say, 25 MPH on a bicycle, or 60 MPH on a motorcycle) when the steering suddenly "breaks" so you can't turn the bars right. It's a little bit more stable, but as soon as anything makes you want to steer, you're screwed. This brings up vivid memories of bicycle crashes when I was young, for me.
The point of this thought experiment has hopefully been clear. If you can't countersteer your two-wheeled vehicle, you're going to fall over.
I hope this clarifies what countersteering is, and what it isn't. This is a subject that you can't just think your way through without any practical experience. Go grab your bicycle or motorcycle and really think about what you're doing, as you ride. Find a big empty parking lot and actually practice steering with and "without" countersteering (whatever form that "without" may take for you). Try leaning your body. Try snapping the bike over by countersteering. It really works, and it's really really effective. Get yourself to the point that you naturally and instinctively countersteer. It's the only way to quickly and precisely steer a bicycle or motorcycle, and it can easily save your life.
Quiet disclaimer: I'm still teaching myself to countersteer. Five years on a motorcycle, nearly every day, and I still have the bad habit of thinking "turn left" without consciously pressing on the left bar most of the time. It's not easy to do. I amaze myself with the speed and power of countersteering nearly every time I make a conscious swerve. Keep at it -- I've improved, and you will too.
Our own IanJ has produced a video which explains this concept quite well. Watch it here.