Counter Steering | The interesting physics behind it

Counter steering is an amazing technique used by many bike riders, and is very useful when making a quick turn and doing some bike stunts like this. At first, counter steering looks counter intuitive, you turn the handlebars to the left, but the motorcycle makes a quick right turn. What are the physics behind this strange phenomenon? Let’s explore.

[hadisemsmeni]

This actually saved my life once, i was going very fast then suddenly a car popped up without checking the road and i countersteered and almost crashed to it by some centimeters!

[anandhugopan]

Glad to see him wearing a cap, safety first.

[carjac]

Counter steering is basically a natural way to turn a bike, too natural that a lot of riders doesn't realized they were using it all the time. It's the only way to turn while speeding. There is no such thing as "normal steering". Direct input steering is only used when the bike is slow enough that the torque it produce isn't enough to lean the bike, you use it at extremley low turtle speed. But once you start to gain some speed it will always be counter steering, no other way. The front wheels will always follow where the bike is leaning not where the rider turns the handlebars.

[AlexEinherjar]

Pixar's Cars taught me all I need about counter steering.

[many_lives]

Literally everybody does this wether riding a bike or a motorcycle. Our sense of balance is just so good we always do it without thinking about it.

[tommeyer]

This give the false impression that a rider can choose between direct input steering and counter steering, as if it were a matter of personal preference. That advice can get someone killed.

You cannot steer a motorcycle at public road traveling speed with direct input steering. You’ll go the opposite direction of your intentions, either off the road or in to oncoming traffic.

[aldofg]

3:48
".. the driver cleverly adjust the angle.."
Decided to hit the sidewalk

[kayakexcursions]

This guy has never rode a motorcycle. You always countersteer going over ~20mph. You can't just lean a motorcycle like he points out, the gyroscopic motion of the wheels prevents this.

[tmsu]

I’ve never seen a more complex explanation to counter-steering than this.

[hxirek]

Actually, the "falling down" in the countersteering example is a bit "BS" - if you stop applying force to the handlebars, the bike will not keep leaning further down, as it is already balanced. Also - you always countersteer on a 2-wheeled vehicle, even if you do not think you do.

[squeaky]

He’s not wearing a helmet, how unsafe!

[Red-yrtm]

It's helpful to break down a turn into two stages, as follows:
1. the initiation of a turn
2. being in the state of a constant radius turn.
The physics and principles involved are identical for any two wheeled vehicle, from a bicycle all the way through to a heavy cruiser style motorcycle, the only differences being the level of forces (rotational, gyroscopic etc.) involved - i.e. the heavier the machine and/or the faster the speed then the higher the forces.
The principles also apply to any speed where your feet are not in contact with the ground (and so are not able to apply vertical forces to alter the dynamics in this way).
There is no magical speed threshold where things change - you don't suddenly apply a different technique above a certain speed.
Firstly let's deal with stage 2 from above - i.e. being in a state of a constant radius turn (ignoring for the time being how we got there). If we are turning left then the bike will be leaning to the left and the front wheel will be turned left [I am assuming we are talking here about regular road riding, not specialized forms of riding such as speedway/flat track riding etc.]. At higher speeds the lean will be greater and the turn of the front wheel will be less (and imperceptible at very high speed, but turned nonetheless). At slow speeds the lean will be less and the turn of the front wheel will be greater. There is no other way for the bike to be in a state of turning.
There have been some comments in this thread that the bike is turned by "leaning". Whilst this is true (together with the front wheel turning in the same direction as the turn, however slight and imperceptible it might be) it only addresses stage 2 of the turn.
In order to initiate a turn (and therefore make the bike lean in the first place) you have to do something, because a bike travelling in a straight line is stable and wants to remain in that state, the higher the speed the more stable it is. There is only one way to do this and it is counter-steering. If you want to lean the bike to the left (in order to turn left) then you have to counter-steer to the right. This is only for a brief moment to initiate the lean (and hence the turn). You can try to lean the bike by a shift in your bodyweight (by pushing down on a foot peg, pushing down on a handle bar (down, not forward) or shifting your arse to one side) but it will be fairly ineffective (and the higher your speed and/or the heavier your machine the less effective it will be). Even if you think you are initiating the lean by a shift of bodyweight (which some comments on here have described simply as "leaning" - which can really only mean moving your body and hoping the bike will follow) you are still counter-steering. If you were to test that theory by removing your hands from the handlebars (please don't) and shifted your bodyweight in an attempt to create a lean, then the bike will AUTOMATICALLY counter steer itself in order to try and balance the forces. A safer way to demonstrate that is to push a bicycle from the side holding the saddle, at walking speed. Make sure it is level and going in a straight line. Pull the saddle towards you to make the bike lean to the left (in my example I am walking to the left side of the bicycle). The steering will automatically go right initially before then automatically falling left into the direction of the lean.
If your feet are off the ground then you cannot turn, at any speed, without counter-steering. You will do it subconsciously and do not need to think about it.
Most children learn to ride a bicycle very easily at a young age simply through experimentation. They don't need to be taught anything, and certainly not the theory of counter-steering! Despite that, they are counter-steering. We would normally call it "balancing". Balancing is nothing more than a succession of very small counter-steers to stay upright on a bicycle, particularly noticeable at lower speeds. The human brain learns it, along with millions of other things, intuitively and instinctively.
To quote Top Gun Maverick, "Don't think, just do".
You will instinctively know how to turn after a little practice. You don't need to be taught it or give it a name.
Did anybody teach you how to turn when walking? no, didn't think so. Most new motorcycle riders can likely ride a bicycle and have been counter-steering all their life without giving it a name, without knowing it even had a name and without knowing all the underlying physics, because it's all unnecessary.
Conscious and deliberate counter-steering however is likely to make you a more proficient rider with better bike control. There's nothing
different about it to subconscious counter-steering but you are likely to be able to induce greater lean, quicker turns and feel more in control (once you have got used to it).

[davidscott]

This is especially important when you are traveling at a high rate of speed and the gyroscopic forces of the wheels fight your ability to lean the bike with only your weight shifting.

[gsegallis]

I couple of clarifications: Counter steering isn't really a "technique" as much as it is a law of physics. You don't really get to "choose" how to steer a motorcycle. Which way you turn the handlebars depends primarily on how fast you are moving. At low speed (and pretty much how you steer a bicycle), yes you can lean into the turn and pull the handlebar in the direction of the turn. It is the angle of attack of the front wheel that turns the bike at low speed. At high speed this never works and you ALWAYS counter steer. The reason is the counter steer moves the bike out from under you and causes the necessary lean. At that point it is the lean and the DEFLECTION of the tire (not the angle of attack) that causes the bike to turn in the direction of the lean. It is impossible to turn a bike at high speed by moving the handlebars in the direction of the turn, thus counter steering is NOT a technique one chooses, but rather is the only way to turn a bike at speed. Don't believe me, tape a paint stick to your handlebars and go try some low speed turns vs high speed turns, and see if you have more than one option in how to turn your bike at a given speed.

[bikemikesguitartopics]

and stay off the painted lines or you are going down anyway, especially if wet.

[sam.merritt]

As many people have pointed out, there aren't 2 ways to turn. There is one way to turn, countersteering. What matters is whether you are doing it consciously and knowingly or if you're just doing it because it's what feels right. But everybody does it all the time period

[MatHelm]

"A technique used by many riders"?!?... It's used by ALL riders.

[muffin_simp]

FYI, everyone who rides properly ALWAYS countersteers. Unless you want to die, you don't steer the first way. Counter steering is the ONLY way to corner safely.

[jdabel]

You lost me with your opening statement. "Counter steering is used by many bike riders"? I think you mean counter steering is used by all bike riders, they just may not be aware of it. You don't get to choose whether you use physics.

[judxmud]

Based on the level of understanding expressed by the authors of this video, I think I am qualified to do a video on quantum theory.