johngwheeler

Dean V

Aren't both definitions the same thing?
2 is just a more subtle version of 1.
I can't really see the relevance of conscious counter steering on a bicycle anyway as the forces are so low and a bike is very easy to tip into a turn anyway.
More relevant to a motorcycle where the mass is much greater, inertia higher, and tyres alot wider.

DaveSSS 

Anyone who's taken a motorcycle training course knows the answer. To make the bike turn right, you push on the right side of the bar. Then the bike leans to the right and turns to the right. Pushing on the right side of the bar turns the tire to the left.

If you don't apply pressure to one side of the bar or the other, it will go straight, all by itself.

The problem with bicycles is that it requires so little pressure to make a turn, that it's not obvious what's going on. I've done high speed turns on a mountain descent, using only an open hand on the hooks. Push on the right side to turn right. Quite pushing and the bike straightens up, all by itself.

tyrion

+1

johngwheeler

Now that I think about it, you're both right.

When riding my (drop bar) bike using method (2) it feels like I'm just putting my weight directly downward on the (inside) bar - but in reality, I expect I am actually applying a turning force to the bar in the opposite direction of the turn. It doesn't feel like this because it appears to have no visible effect on the angle of the bars, which might even actually be slightly turned in the same direction as the turn when going slowly.

I've never ridden a motorbike, where it sounds like counter steering is a more deliberate action.

Thanks for the clarification!

Trakhak

The OP says "I have read that this [i.e., counter-steering] is in fact essential to making the turn."

If counter-steering were essential to turning a bike, it wouldn't be so easy to steer a bike solely by leaning in the direction in which you mean to turn, i.e., without touching the handlebars.

MoAlpha

Not disagreeing with any of the above, but the way I prefer to think about it is that to induce lean into the turn, the contact patches have to be pulled just slightly outside the path of the bike. You do this by steering outside and relying on the inertia of the bike to lean it the other way. If you don't do this and steer directly into the turn, you induce lean in the wrong direction.

I don't quite get definition 2, as stated.

wphamilton

It's a good question because people tend to have their own concepts about it.

I think we first have to nail it down that we're talking about counter-steering in the context of a turn. As opposed to the constant corrections we make just trying to ride straight. Yes, both involve turning the wheel, and a change in balance, and moving the bike under the center of gravity. But there is one difference, and it can be an odd blind spot even with people who (actually do) know physics. So let's say, we're only talking about initiating and executing a turn.

Break it down, it's fairly simple as MoAlpha describes. The bike will track wherever the wheel is pointed; that is first and basic. The wheel must be turned toward the direction of turning, period. Let's say left turn. Momentum* will push your body outside of the curve -to the right - therefore you have to lean left to balance that. That leaning left (inside) is the result of turning the wheel the other way to the right, and that's what we define as "counter-steering". It moves your wheels to the right, away from your center, which causes you to be leaning to the left. That's all there is to it. Moving the wheels off-line to help you lean in the direction you want to turn. We do it at the beginning and/or several times all the way through the turn.

*(let's not get hung up on centripetal vs centrifugal please)

Moving along in a straight path, we need constant corrections. Those corrections move the bike back under our center of gravity, to regain our balance, no lean. Counter-steering moves the bike away from under our center of gravity, to unbalance us, create a lean. The two are fundamentally different, and why we call it "counter" steering. Believe it or not, that's controversial.

ridethetown

On road, I never like to think of initiating a turn by turning your front wheel either direction, that's a quick way to end up on the ground. I think of it more as counter-balancing than counter-steering. Weight on outside foot, inside arm straight. So both 1 and 2 are I guess correct, but I don't like to think of it as turning my bars if I'm on my road bike. All I ever really think about is my outside foot - if it's properly weighted I can point the bike wherever I want through the turn.

If you really want to feel counter-steering, get on your MTB on a moderately fast downhill with sweeping turns. With the slower handling you can really practice and feel counter-steering as the back wheel drifts a little.

Notso_fastLane

This is partially true. The physics is a little more complicated than you can easily perceive while riding though.

When you are riding hands free, your ability to initiate a turn is pretty limited. But if you could put a high speed camera on the bike that was focused on the handlebars, you would see them countersteer naturally, prior to the turn.

On a motorcycle, it's much more noticeable because of both the higher speeds and the increased weight. As a matter of fact, the ability to steer a motorcycle by shifting your weight alone is almost negligible, and you more or less just keep going in a straight line.



Lots of good videos about this from a top motorcycle safety/riding school.

https://www.youtube.com/results?sear...ountersteering

tyrion

I don't think that's entirely true. A bike will turn in the direction that it's leaning, even if the wheels are perfectly straight, because the circumference of the tire on the leaning side is smaller than the circumference of the center of the tire. When leaned over the contact patches become conical.

This is much more apparent at motorcycle speeds and fat tires, but the physics still apply to bicycles' slower speeds and skinnier tires.

Notso_fastLane

Is it a rule of the internet what whenever someone makes a statement of the form " <statement is how things work> period." that they're wrong?

I've taken and taught Motorcycle Safety Foundation (MSF) courses. I've got a motorcycle racing license, and won a state championship in 2014.

I'm also an aerospace engineer with a lot of physics background.

A turn on a 2 wheeled vehicle at anything above walking speed is initiated by turning in the opposite direction of the turn. Once the lean angle and turn is established, the steering wheel is then returned to the direction of the turn, allowing the vehicle to track along the arc created by the slight offset in the contact patches.

I tried to find a good video that demonstrated this part, but didn't have any luck with a couple minutes on youtube.

wphamilton

Because it causes the wheel to turn. Imagine it (exaggerated) as a cone on the ground.

wphamilton

Which is exactly what I said.

The unwritten rule should be: when it doesn't seem right, and you're stating the obvious as an argument, you probably misread something.

MoAlpha

Sitting here, I can't imagine a bike turning without skidding unless the fork is turned.

wphamilton

Yeah, I think so also, you at least need something that causes the frame orientation to turn, to remain tangential to the path's curve. In any event a bicycle tracks the path where the fork is turned. Counter-steering is to balance the forces, period. Technically you could even use other forces without the counter-steering in fact.

I'm already getting static here so I'm not even going to try to go into OP's other question. I'm out after this.

colnago62

Paralysis by analysis. I don’t think about it. I look to where I want the bike to go and then I go there.

ridethetown

This exactly.

The wheel doesn't have to turn into the direction of a curve. If you've ever roller bladed (yeah, I know...) you can very easily stand on one leg and turn left and right, arcing turns and tight turns no problem. No skidding and - at least on the roller blades I've seen - no turning of wheels. Same true for bike, motorcycle, etc.

wphamilton

OK I said I was out, but just this last time ... the wheels DO turn left and right on your roller blades - just not relative to the shoe. As you turn, the wheels rotate about a vertical axis.

Their motion is ALWAYS aligned with where the wheels are pointed (*tangent to the curve in your example). If you want to understand counter-steering, the first step is absolutely that you must accept that the bike is tracking where the wheel points. These objections are frankly trivial. You can have wind blowing you, gravity pulling you to one side, riding inside a rotating barrel etc etc and yes the bike will go that way. But all irrelevant to the question.

Done now, I promise.

Darth Lefty 

@wphamilton, yes the front wheel must track the turn, just as it must go straight when the bike is going straight. Countersteering is a perturbation, not a constant force. To turn right, you move the steering ccw, which drives the bike out from under you to the left, you and the bike start to fall to the right, you don't need to push any more, its stability corrects it to follow the lean angle. Once the bike is leaned over the steering geometry matches the steering turn angle to the lean angle. It does the same thing if you stand next to it and lean it over, or if you launch your BMX into a hedge. This fact is handy for maneuvering a motorcycle out of the garage. If you are turning no-hands you initiate by putting your center of mass off the center line for a moment, and the stable steering goes off-center to compensate.

All of this is way more obvious on a motorcycle. They have more mass, more head tube angle, twice as much trail as a bicycle, heavier wheels with more rotating inertia, and the added stability makes the steering effort much higher, especially at freeway speed. So it's heavy enough that the forces you put into it are obvious. If you try to ride no-hands on a motorcycle you have to move your body with much more effort to get any effect at all.

CliffordK

One thing that I'll do periodically which demonstrates the dynamic need for "counter-steering" is I'll be riding along, and see something directly in front of me (pot hole, road debris, etc). So, I'll for example, do a quick swerve left without counter-steering. Doing so tosses the rider to the right, and one essentially hops around the object, then has to do a significant steer maneuver to recover. Obviously it wouldn't do to do an opposite lean while actually going around a corner.

I gave up hands-free riding years ago after a crash and damaged wheel. But, I wonder if each bike has a natural steering curve based on the head tube angle, fork rake/trail. And, thus, using the counter-steer, or whatever to imitate the lean, then the lean mostly takes one through the rest of the turn.

Darth Lefty 

I guess mentions are broken again

wphamilton

It notified me, but I promised I was out ...

RedBullFiXX

We are all countersteering past 5mph, it's just so subtle hard to notice
For the brave, take your hands off the bars, try leaning at 20+ mph, see how tight a radius you will get compared to hands on

Countersteering in 4w vehicle has nothing in common with 2w

Abe_Froman

All steering is counter steering. It is not possible to turn without counter steering. If you just regular steer, you will fall down, immediately.

Counter steering with no hands works exactly the same way as counter steering with hands. You're still making the front wheel turn left to tip the bike to the right into a corner.