Motorcycle Countersteering

[Admin]

Kevin Cameron has been writing about motorcycles for nearly 50 years, first for <em>Cycle magazine</em> and, since 1992, for <em>Cycle World</em>. (Robert Martin/)

We all know how steady-state turning of a motorcycle or bicycle works, how it is made possible by two torques canceling one another such that the machine neither falls over nor rises upright.

One of the two torques comes from the weight of bike, fuel, and rider(s), acting as if concentrated at the center of mass, in turn acting on a lever whose length is measured from the vertical projection of that center of mass onto the pavement below, over to a line roughly connecting the bike’s two tire footprints. This torque tends to make the bike fall over (on many bikes, the center of mass when upright is about 22 inches above the pavement, about 47 percent of the wheelbase back from the front axle).

Related: How to Countersteer on a Motorcycle Correctly

The other is the lateral acceleration caused by turning, acting on a lever arm equal to the height of the center of mass above the pavement, in the leaned-over turning attitude. This torque tends to make the bike stand up.

When the two forces are in balance, the bike remains at a constant angle of lean and turns steadily. The front end’s geometry tends to steer the front wheel into the turn enough to maintain this balance, with adjustment from the rider as necessary.

The question is: How, starting from straight-line upright stability, does the bike reach this state of balanced turning?

Early Countersteering Thoughts

Back when this discussion was young, some amazing answers were proposed. Most basic was, “I steer into the turn, just like I do in my car.” In those innocent days of the 1960s, riders giving this answer were given a piece of string and the instructions, “Tie this to the right handlebar, get your bike going straight on a clear piece of road, take your hands off the bar, and then pull gently on the string to make the bike turn right.”

However, when the rider did gently pull on the string, it steered the front wheel to the right. As the front tire began to track to the right, it ran out from under the bike’s center of mass on that same side, causing the bike to camber (lean) to the left.

Another popular explanation: “I use upper-body lean. I lean my body in the direction I want to steer.” Now imagine rider and bike in zero gravity. How does the rider lean his or her upper body to one side? By pushing the bike in the opposite direction. You cannot just will yourself to move in a given direction! In order to move, you have to push against something—in this case, the motorcycle. Again, back in the bad old days, the rider was told to demonstrate this technique without touching the handlebars. Results? Nothing that you’d count on using to ride across town or avoid normal traffic hazards.

Yet another popular explanation: “It’s something to do with gyroscopes, I think.”

Look at the position on Jack Miller’s hands; he is turning left, but his left hand is slightly ahead of his right, demonstrating countersteering. (MotoGP/)

Related: Riding Skills Series: The Art of Countersteering

The wheels of bicycles and motorcycles do have the properties of gyroscopes, but in the April 1970 issue of Physics Today David E.H. Jones describes how he canceled the gyro effect on a bicycle by adding “a second wheel, clear of the ground, arranged so that I could spin it against [in the opposite direction to] the real front wheel and so oppose the gyroscopic effect.”

Jones said of the result, “It could be easily ridden, both with the extra wheel spinning at high speed in either direction (or) with it stationary.”

Motorcyclists know that steering resistance increases with speed, but this opposes rather than enables our effort to steer.

Seeing Countersteering in Action

Where does this leave us in our efforts to understand motorcycle steering?  It leaves me on a wet 1990s’ morning at New Hampshire Speedway (Loudon), turn 3, watching Superbikes come straight at me just before they peeled off to their right. What I saw was the trace of each bike’s tires in the wet, initially steering away from the turn and so causing the bike to fall over into the turn. Once each bike reached the lean angle its rider desired, its steering trail exerted a natural torque on the front wheel, turning it into the corner.

This makes mechanical sense because the tire forces created by steering away from the turn generate side thrusts at ground level. But because the motorcycle’s center of mass (bike, fuel, and rider) is roughly 2 feet above ground level, this creates a torque tending to roll the motorcycle in the direction opposite to the action of steering away from the turn. And this is countersteering.

Related: Motorcycle Steering And Hand Pressure

It’s natural for some folks to believe that “upper body lean” is the mechanism of steering, for if you lean right, you exert some accidental pressure on the bar to the left—and vice versa. And that is countersteering.

Learning to Ride

We learn to ride a bicycle by persistently trying until we find a set of muscle movements and pressures that works. We do not learn by sitting through a step-by-step analytical lecture from a learned professor, complete with PowerPoint. This means we have little understanding of what our bodies are doing; we just discover actions that work. I took my first bicycle to a grassy slope and pushed off.

Time and again the bike and I just fell over in a heap. It was frustrating! When I complained to my mother, she just said, “Keep at it. Eventually you’ll get it.”

And eventually I did. What I “got” was what we all get from this experience: the conscious or unconscious understanding that to remain upright on a two-wheeler, you must constantly steer so as to keep the tire footprints centered under the combined rider and bike center of mass.

Not only did we learn to ride upright by keeping the bicycle’s roll angle at vertical, we also instinctively learned how to roll it in either direction, left or right, by steering in the direction opposite to the desired lean. This ability to control roll motions is built into the process of balancing. And it was fun to veer from side-to-side as we pedaled.

Transitioning from a left to right, the clip-ons are pushed left to stand the motorcycle up and begin the transition to the right. (MotoGP/)

Related: Body Positioning And Steering Techniques

I learned two things on that grassy slope:

1. How to avoid falling over: By steering to keep the wheels centered under the bike and rider. The engineers call this “avoiding the <a href="https://www.cycleworld.com/why-do-motorcycles-wobble-and-weave/">overturn mode</a>.”
2. And conversely, how to lean the bike by deliberately <i>not</i> keeping the wheels centered under it, but by steering them out from under it. This is called <i>countersteering</i> because to roll the bike to one side, we steer slightly in the opposite direction (that is, <i>counter</i> to the desired roll direction).

Steering a car is a one-step process: turn the wheel in the direction you want to go. But steering a motorcycle requires that first we lean the bike in the direction of the desired turn, so we can set up the balance between turning force and gravity.

I certainly wasn’t aware of what my body had learned on my grassy slope. I was just very pleased that I could ride a bicycle. Only years later when I encountered discussion of how the process works did I hear about countersteering. It’s possible that some riders never have. Yet they still ride.

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[Tiggie]

popcorn at the ready for this one !!

[Guest]

 

'We all know how steady-state turning of a motorcycle or bicycle works, how it is made possible by two torques canceling one another such that the machine neither falls over nor rises upright.'

 

Yes of course we all knew that.

[Gerontious]

I’ve developed a strange craving for fig rolls. I might have to rush out and buy some. Just because I can.

[keith1200rs]

Someone told me motorcycling is controlled falling over. Very perceptive.

[billy sugger]

I'm saving this to read tonight if I can't sleep, as it seemed to work with the book I was reading last night 

[Grumpy Old Git]

It is all Newton's fault - If he not invented the Apple Tree, it would be so much easier. 

[Fiddlesticks]

Gravity is a myth, the earth sucks.

[gymwitch]

12 hours ago, Gerontious said:

I’ve developed a strange craving for fig rolls. I might have to rush out and buy some. Just because I can.

Ohhhh fig rolls !!! Not had one for years. I'd steer the whole packet into my gob though

[Bender]

21 minutes ago, gymwitch said:

Ohhhh fig rolls !!! Not had one for years. I'd steer the whole packet into my gob though

They are a huge disappointment it's not like you can actually roll them. 

[billy sugger]

Fig rolls and garibaldi biscuits should both be consigned to the deepest depths of hell (or Bradford, if they can't afford the bus fair) 

[Bender]

18 hours ago, billy sugger said:

Fig rolls and garibaldi biscuits should both be consigned to the deepest depths of hell (or Bradford, if they can't afford the bus fair) 

I will give them them the bus fare, how much is a bus ride these days @Stu? £60000,000000,77778.27p

[Stu]

12 minutes ago, Bender said:

I will give them them the bus fare, how much is a bus ride these days @Stu? £60000,000000,77778.27p

 

Your halfway there........