Steering Single-Track Vehicles
Countersteering is mentioned frequently in motorcycle magazines and in classes both beginner and advanced. But what's the big deal? Don't we all know how to steer our motorcycles? You didn't make a right turn when you expected to make a left on your last ride, did you?Every single-track vehicle steers in the same way. This includes bicycles, motorcycles, unicycles, the bicycles-with-wheels-replaced-by-skis that I occasionally see at the ski area where I teach — basically any vehicle which has to be balanced. We all know how to steer them, but we don't know how we steer them; we just do it, the same way we walk or sing. And here's the reason it's important: In an emergency, we often do it wrong. The Hurt Report (do a web search on "Hurt Report motorcycle crash" for a 55-item summary of the findings of this important research paper from about 1980) found that among crash-involved motorcyclists, "The ability to countersteer and swerve was essentially absent." If a motorist pulls out into the path of a motorcyclist and then stops, requiring the rider to swerve around the car, it is common to find that rather than successfully swerving, or even just going straight and clipping the car, the biker actually goes the wrong way and hits the car amidships.
How can this happen? It happens because we all know that to steer a bicycle or motorcycle, you turn the bars to point the front wheel the way you want to go. But that isn't the way it works, and that isn't what we do when we make our routine turns in traffic.
To understand what we do and how we do it, first consider an aside. Suppose I'm standing in front of you balancing a broom on the palm of my hand, bristles in the air. If I now take a step toward you, what happens to the broom? I and the bottom of the broomhandle move toward you, but the top of the broom stays where it is, with the result that the broom falls toward me and hits me in the head.
So to move toward you, what do I need to do? That's right, I first move the bottom of the broom away from you. That gets the broom tilted in the right direction, and once the tilt is established, then I can move myself and the entire broom in your direction.
Here are the important points:
- The bottom of the broom must first move in the opposite direction of the final intended movement.
- This establishes the lean in the intended direction.
- This happens quickly. If you blink, you'll miss it.
You're not there yet, of course; the bar's still turned right and so the front wheel is still tracking right. To understand how the front wheel gets turned left to continue the turn, you need to look up some works on motorcycle suspension and understand rake and trail and caster. I don't want to go there, I don't understand it well myself. But, analogously to the points with the broom, here are the salient points about a single-track vehicle's turn:
- The bottom of the vehicle must first be moved in the opposite of the intended direction, to establish the lean.
- That initiation movement happens quickly.
- Once the lean is started, the front wheel is pointed in the direction you expect it to be pointed. If you look at a motorcycle in a turn to the right, the front wheel is pointed right, not left. But it didn't start out that way.
To turn to the right, you press the bar forward with the right hand.
That's why it's called countersteering; you do indeed briefly steer the "wrong" direction. We all do it; it's the only way that single-track vehicles turn. But usually the movement is so subtle that we don't realize exactly what we do to turn. We look at the wheel in a left turn; it's turned to the left; we conclude that we turn left by turning the wheel left. We don't. And that's how we get into trouble when that bozo pulls out in front of us and then stops. We gasp and turn the bar left to swerve left, and the bike goes right. Then Harry Hurt and his researchers show up, and they write "The ability to countersteer and swerve was essentially absent."But don't take my word for it. Find a large empty parking lot, take off at 15mph or so, and press gently right. See what happens. Or take an Experienced Rider Course from the Motorcycle Safety Foundation where you'll spend half an hour working on your swerve. If you watch from in front as someone else does it, you can easily see the front wheel go first in the "wrong" direction, then recover and go the "right" way.
Body Steering
There's a considerable school of thought that claims you can steer a motorcycle by shifting your weight. We can all ride a bicycle and steer it through turns with no hands on the bars. Couldn't you do the same thing on a motorcycle? You certainly can, at least with some motorcycles. The movie Faster, a chronicle of the MotoGP racing seasons of 2003 and 2004, has a scene showing Valentino Rossi standing on the pegs of his motorcycle after winning a race, hands in the air waving to the crowd, flowing through the turns with not a touch on the bars. And this video of Christian Pfeiffer, starting at about 1:50, shows him doing radical turns at slow speed with his hands in the air.However, not every motorcycle is so amenable to weight shift. Keith Code, owner of the California Superbike racing school, modified one of his school's Kawasaki ZX6Rs with an additional set of bars mounted above the usual set. The new set did not turn the wheel. You get up to stable speed and then switch to the rigid set of bars and swoop your body around, hang off, jerk on the bars, whatever you like, and see what the effect is on the bike's path of travel. You can read about the result here. Not to keep you in suspense, the result is that the bike makes only the slightest turn in response to a weight shift.
Some people speculate that the reason their motorcycles don't turn with body weight shifts and a bicycle does is that even the lightest motorcycle weighs more than twice as much as even the heaviest rider, while even the heaviest bicycle weighs only a fraction of even the lightest rider. The examples of Rossi and Pfeiffer show that this cannot be the full answer. I personally think (without proof) that steering geometry is the key factor. Some bikes are more stable than others. I suspect (again without proof) that Rossi and Pfeiffer couldn't do what they're shown doing if they were riding cruisers.
It's interesting that in the Pfeiffer video, you can see the countersteering effect on the front wheel. The wheel momentarily moves to the right, causing the bike to lean and then turn to the left, though the initial movement is caused by weight shift and not direct input to the handlebars.
Whatever you do, don't be one of those crash-involved riders whose "ability to countersteer and swerve is essentially absent." If you want quick response to an emergency, on any motorcycle, use the handlebars!