What is countersteering?
Written March 29, 2007
Countersteering is a source of contention among motorcyclists. Some believe it exists or is effective, others don't, and some are effectively agnostic. In this article, I hope to explain to you why it exists, how it works, and why you want to know how to use it.
I don't have any "official" credentials to offer on my knowledge of this. I've done experiments with my own bikes to satisfy myself that what I present here is correct. I urge you to (safely) do your own experimentation. If you are riding a motorcycle and haven't yet taken a safety training course, such as those offered by Team Oregon or the MSF, I urge you to take one as soon as you can.
First, a quick definition. Wikipedia (currently) defines countersteering like so:
When riding a bicycle or a motorcycle, countersteering is a method of initiating a turn by a small, momentary turn of the front wheel, usually via the handlebars, in the opposite (counter) direction.
That's a good definition, but it's dry and isn't very illuminating. (Not to criticise Wikipedia -- it's just that you're probably here because the textbook explanations haven't helped.) Note that an important part you may have skipped is that it's the way of initiating a turn. Don't confuse countersteering with steering where you want to go, as long as the bike is balanced.
My own (dry, unilluminating) definition is like so:
Countersteering is the act of turning a two-wheeled cycle in one direction by momentarily steering the front wheel in the opposite direction.
Note that there's nothing in there about steering into a turn. You will obviously need to, especially at low speeds, but that's just steering, and is no longer countersteering.
Wait, This is Long, Why Should I Care?
In short, the reason you care about all this is that the only safe, sure way of controlling a bicycle or motorcycle is with countersteering. Shifting your weight or thinking "lean right" aren't enough. Countersteering is precise, happens exactly as you command it to happen, and can be applied at a moment's notice. It will save your life. It will make your riding better.
If you'd rather watch a quick version, try this on for size:
Or try on the...
Countersteering is the act of turning a cycle's wheel away from the direction of an intended turn. This unbalances the bike toward the intended direction of turn, using centrifugal force and the bike's own forward momentum. Countersteering primarily uses the front wheel's trail as a lever arm to accomplish this. Countersteering is only that moment of unbalancing the bike, and completing the turn is simply called steering.
What is Balance?
To start out with, let's establish some basic ideas about balance. Imagine, if you will, that you're standing with your right foot two feet (or so) in front of your left, so they're in line. Naturally, you're going to be balancing your body in a side-to-side way rather than the front-to-back you normally do when they're next to each other in a natural standing position.
Now, imagine that your left foot, in the back, is glued to the floor. It can't move, for the purposes of this mental experiment. Your right foot, in front, can move side to side, but you can't move it backwards.
Just so you know why I'm putting these weird limitations on the experiment, this simulates the wheels of a motorcycle or bicycle. Your right foot is the front tire, and your left foot is the rear tire.
Now, let's add some dynamism. If someone pushes you to the right, how do you move your forward foot? You pick it up and move it right, to counteract the force, so you don't fall over toward the right. A push to the left? Move your foot to the left. Feel free to stand up and try it out, it may make more sense if you actually do it.
Now, imagine that you want to lean to the left. Which way do you move your foot? It goes to the right, to push you to the left. It's not much of a move, but certainly if you move your foot to the left, that's not going to give you much lean to the left. Sure, you can do it, but if you had springs holding you upright, you'd have to move your foot right and push against the spring force.
This is a silly sort of introduction, but it gives us the foundation of how a two-wheeled, single-track vehicle like a bicycle or motorcycle works.
On your Bike
Now, let's move our imagination to the bike. It doesn't matter if we're talking about a motorcycle or a bicycle (or a weird ski-based vehicle which has two skis inline like the tires on a bike).
You can try these things on your bike, but if you do, do it in a safe area where you don't have to worry about cars or potholes or dogs or anything else. For some of this discussion, that means a racetrack, so keep that in mind before you try everything out.
Now, let's consider low speed. Many people argue that countersteering doesn't exist at low speeds. Indeed, that seems to be the case: it feels exactly as though you can just turn the bars toward your intended turning direction, and you go there. I'm talking about low speed, like 3-5 MPH.
Think back to our earlier experiment, with your feet in line with each other. Stand up now and do it. See, if you shift your butt just a little bit to one side, you can start leaning the other direction. But if you don't shift anything (don't cheat with your arms, I'm watching), you can't start a lean. This demonstrates one way in which countersteering "doesn't exist" at low speeds. Just shift your butt a little bit, and you can start steering the direction you want to go.
Now, try going the other way. Without shifting any weight (you'll have to do this on the bike, unless you have some kind of cool slide-o-gizmo for the standing experiment), press very lightly on the right handlebar. That turns your wheel to the left. You immediately and decisively fall over to the right. Gently! I'm not trying to make you fall over, so turn into the fall to pick the bike up before it goes very far. Consciously countersteering at low speed can drop your bike on its side before you know what happened.
What does this demonstrate? It shows that countersteering does exist at low speed. Really, go as slow as you want, if you do it without shifting your weight, pressing on the right bar will always make you fall over to the right. That's countersteering. You have to steer left to go to the right. (Although granted, as I showed above, you can do it other ways than countersteering -- that doesn't mean countersteering is an invalid option, though.)
You should be aware that trying to consciously countersteer at very low speeds can be dangerous, as even the slightest handlebar input has a large effect on the bike.
Here is a brief video demonstrating slow-speed countersteering:
Speed It Up a Bit
Now, let's go a bit faster. Call it 12-13 MPH. That's where most people claim countersteering starts working. Gently, push on that right handlebar again. (Or left, of course, either way works the same.) Now, it starts to get obvious, particularly on motorcycles. The bike leans to the right, even though you just pointed the front wheel to the left. The more you turn the wheel to the left (ie, push on the right bar), the faster the bike heels over to the right.
Now, at this speed, what do you do to keep from just falling flat on your right? Turn into the curve. On a bicycle, even at this speed, it happens so fast it's over before you know it. Narrow your focus down to the quarter of a second between when you're going straight, and when you're turning right.
One way of proving that this really happens (particularly at higher speeds) is to set up a video camera as I did above -- near tire level, aiming at the front tire. Ride at the camera, and look for that twitch as you swerve away. You can see that method demonstrated in the following handy video:
Speed It Up Some More
Ok, now we're into motorcycle territory. Bicyclists, if you can find a big open hill, you can demonstrate the same thing, but we're really into motorcycles-only at this point. We're talking about 40-50 MPH.
Find a straight that goes into a curve, or a really big open parking lot. Do the same thing again: at speed, push on that right (or left) bar. The bike smoothly leans over, leaning faster the harder you push. It's really obvious at this speed.
Ah, but now comes the time when you want to stop leaning. The goal isn't to fall over, it's to turn. Now, you steer the wheel back towards the curve -- you reduce pressure on the right bar. On some bikes, you might actually completely relax that countersteering pressure. On some bikes, you'll maintain some pressure on the right bar to keep the bike leaned. Whatever the case, you've reduced your countersteering force to go the direction you want to go.
Ok, now get going as fast as you safely can. The faster the better, for the purposes of illustrating this principle. Let's call it 100 MPH (on a closed track, of course).
Now, give the right (or left) bar a gentle shove. Nothing happens. Push harder. Harder. Now it starts leaning, but you have to push hard. It's still countersteering. You steer left (quite hard left, usually) to go right.
Once you're in the turn, the geometry of the bike will tend to keep it at whatever lean angle you've set -- changing to a tighter or shallower turn will require countersteering to set the new angle. To exit the turn, you must countersteer into the turn to pick the bike up and set it on a straight path again.
(Note: in a previous version of this article, I incorrectly stated that the bike tried to pick itself up out of the turn. This is completely wrong, and I apologize for the error.)
Explaining countersteering is an involved process, which can easily include obfuscating physics references. I'll try to avoid that, and keep it simple. If you want a more technical explanation, it's out there. This is an article for beginners.
First, some background.
Ok, so take a look at this picture. Follow that line down through the fork legs, all the way to the ground. Where that line hits the ground (so the bike geometry experts assure me) is the front wheel's natural pivot point. You'll notice, though, that where the wheel actually hits the ground is behind that pivot point. The distance between the wheel's contact point and that imaginary pivot point is called the bike's trail.
The trail provides a castering force. This is the same kind of caster as you see on wheeled office chairs, or on the front of shopping carts*. The distance between the pivot and the ground-contact point is important -- the longer it is, the stronger the castering force is. That castering force is one of the forces acting upon a bike to keep it upright when it's moving. It keeps the wheel pointing straight forward, by keeping the point of force behind the point of pivot.
* Ever notice how those shopping cart wheels sometimes waggle back and forth? Look at the angle of their pivot -- it's straight up and down. A cycle's rake (the angle between vertical and the cycle's forks) is a vital part of preventing that, so it's not all about the trail.
Another force (although weak) acting on the bike is the wheel's gyroscopic force. This is exactly the same gyroscopic force you can see demonstrated with a child's toy gyroscope. When you spin it fast and set it on edge, it tends to stay upright. The reason for this is involved, but for the purposes of this article, just keep in mind that it happens, and it's real. If you don't believe me, go buy one of your own and prove it to yourself. Wikipedia is happy to explain gyroscopes as well.
Note that gyroscopic force is not very strong, and doesn't really contribute all that much to the stability of a bike, or its movement in a turn. This is detailed in this article. It is certainly a force, and it certainly has an impact, but not as much as you might think.
Ok, we have the forces down. At the top of the article, with our footy experiment, we established the basics of balance. Grab your bike, there's one more thing to demonstrate; this will be easier with a bicycle, but a motorcycle will do if you're careful. Keep a friend handy to help out if you have any concerns about this next one.
Straddling your bike, with the bike straight upright, turn the wheel back and forth. Not much difference, is there? It doesn't really want to fall either way with the wheel turning. That changes when you're moving, but that's not this demonstration. Now, (carefully!) lean the bike slightly over to one side. Turn the wheel towards and away from the lean. The wheel suddenly makes a lot more difference. Try leaning further, as far as you're comfortable with, and turn the bars. In fact, if you go too far over, you can turn the wheel into the fall, exactly as you would with countersteering, to help pick it up again.
This demonstration is mostly to give you a tactile impression of what happens when you turn the wheel with the bike leaned over. The front wheel has a lot of effect.
Now, when you're rolling, turning the wheel has a definite effect, even when you're upright. It makes the whole bike go the direction the wheel is turned (wait for it!). Since the bike is balanced, with the wheels providing the only point of traction, any deflection is going to rotate about the traction point. That is to say, if you steer left, the bike will tend to fall over to the right. Let's examine that in detail.
Imagine you're in a car. You're driving along a straight road. It curves, so you turn the wheel to the left. Your weight (particularly going too fast through a tight curve) is thrown to the right. This is commonly referred to as centrifugal force, which is close enough for our purposes*. The car has four wheels, so it doesn't fall over, but the bike only has two. Yet it reacts in the same way. You turn that wheel left, and the bike falls over to the right, having no extra wheels to catch it. You've unbalanced the bike.
* Check out this article on centrifugal force if you're interested in the nerd's-eye view of why "centrifugal force" sort of doesn't exist.
Now, it happens that due to a complex interaction involving conical sections and a bit of gyroscopic precession, when you lean the bike over to the right, it will tend to turn to the right. Leaning to the right also happily balances gravity against the centrifugal force trying to pull you over to the left. That's actually what happens when you turn a bike -- you're balancing gravity and the sideways force trying to pull you off the bike.
So, this is where things get interesting. Remember those forces that act to keep your bike upright (trail and gyroscopic force)? Those forces always act on the bike, but they get stronger the faster you go. That is, at walking speed (3 MPH), they're barely perceptible. As you speed up, they get stronger and stronger, until at 100 MPH, you're fighting with the bike just to get it to lean over.
This is largely why countersteering "doesn't work" at low speeds. You don't really need it. The feeble forces keeping you upright (trail and gyroscopic) can easily be overwhelmed by shifting your weight or calling upon the faeries, or whatever you like. Surely, it still works, but it's not necessary.
As the bike goes faster, trail and gyroscopic force get stronger and stronger, until they're stronger than you are. Seriously, motorycle racers work out partly to be strong enough to muscle their bikes over in corners.
And It All Boils Down To...
Where this should all come together is that once you understand what countersteering is, and how it works, you are in much better control of your bike. Get countersteering straight in your head, and you can keep your bike upright at the lowest speed, with practice. (Just because your head understands, that doesn't mean your body does, but it will with training.)
With countersteering, you can swerve on command, commence a turn at any point, and come out of it whenever you want to. Sure, you could kind of do that before, but with this understanding, you can do it a lot better, and much more crisply.
So now that you've read through this whole thing, get out on your bike, and practice countersteering. Do it gently, and do it safely, but practice it every time you need to turn that bike. I'm still working on countersteering consciously, and I've been riding since 1999 (or about 1976, if you count bicycles), almost every day.
I hope this has been helpful. If you have suggestions or comments, please drop me a line at reaper at obairlann dot net.
If you've read all this and are screaming, "I want more!" then you may enjoy my older, less well-written article on countersteering.
Copyright 2007-2010 by Ian Johnston. Questions? Please mail me at reaper at obairlann dot net.