best explanation of counter-steering I've heard

[redkow97]

I have heard and seen a billion people try to explain the physics behind counter steering, and while I have always understood the basic principle, it was explained to me in a new way this past weekend that makes a ton more sense than it ever has before.

Hopefully I do this justice in writing...

I take it as common knowledge that a moving motorcycle wants to stay upright (due to the gyroscopic effect of the wheels, and the rotation of the crankshaft).

So it should be equally obvious that you have to "upset" the bike's natural tendencies to get it to turn at speed.

What I think most people fail to grasp is why you have to turn the bars left (albeit an imperceptible amount) to make the bike fall to the right.

Tom (WERA race school Tom) held up a stick (corner worker flag) and set it upright on the table. He said, "if this is a motorcycle, the wheels are on the ground, but the center of gravity is somewhere around here" (in the middle of the stick).

"So in order to make the stick (bike) fall to the right, you can push the top to the right, OR, you can push the bottom to the left, from below the center of gravity."

At speed on a motorcycle, you have very little leverage to push the top of the bike either direction. You have nothing to push off of. But you have COMPLETE control over the front wheel. You can essentially "push" the wheels out from under the bike, and force it to fall.

Maybe other people have easily understood that for a long time, but that was a total "lightbulb" moment for me, all because he was holding a damn stick, and rotating it from the center, instead of the base.

[Likwid]

wow..... that was a lightbulb.... thanks for posting that!

[jporter12]

Nice explanation!

[jporter12]

The only argument I have is how much the crankshaft contributing to the gyroscopic effect. I'm going to say next to zero, but the rest is really good!

[fizzer]

This explanation doesn't really work for me. How by turning your handlebars are you pushing the bike out from underneath you? In order to push the front tire out from underneath you as in the demonstration with the stick, you would need a force pushing the fork directly left or right, which is not the kind of force provided by turning the handlebars. If this were true I would think instead of handlebars we would just need a sort of joystick front fork which only moved left and right. The bearings in the steering head prevent any side to side lever motion like that, and allow only rotation along the axis of the bearing.

The only explanation that works for me requires an understanding of angular momentum and torques, and your right hand. If no one else beats me to it I can take some pictures later tonight and try to explain it. Also perhaps there is already a good set of diagrams (or even video!) available online, but I don't have the time right now to look for them.

[Uncle Punk]

288

[Tpoppa]

That's a good explanation. By leaning your body right, and for a moment pushing forward on the right clipon. The contact patch on the front tire is moving slightly left causing the bike to tip to the right? ...is that what he was saying???

[redkow97]

This explanation doesn't really work for me. How by turning your handlebars are you pushing the bike out from underneath you? In order to push the front tire out from underneath you as in the demonstration with the stick, you would need a force pushing the fork directly left or right, which is not the kind of force provided by turning the handlebars. If this were true I would think instead of handlebars we would just need a sort of joystick front fork which only moved left and right. The bearings in the steering head prevent any side to side lever motion like that, and allow only rotation along the axis of the bearing.

The only explanation that works for me requires an understanding of angular momentum and torques, and your right hand. If no one else beats me to it I can take some pictures later tonight and try to explain it. Also perhaps there is already a good set of diagrams (or even video!) available online, but I don't have the time right now to look for them.

Complicating it with all the minute variables and details complicates it beyond comprehension for your average joe.

The point (for me) was demonstrating why the front wheel must turn the opposite direction from which you want to turn.

the front of the bike has to turn left so that the center of gravity (which most won't realize is higher) will fall right.

[serpentracer]

http://www.youtube.com/watch?v=XhRydTnSDes&feature=channel_video_title

[RVTPilot]

288

2. We've had this conversation.

[ReconRat]

The only argument I have is how much the crankshaft contributing to the gyroscopic effect. I'm going to say next to zero, but the rest is really good!

A fair amount, I think. For those bikes with a crankshaft that is side to side. The evidence is with those other bikes that have crankshafts that are front to rear. They show a fair amount of influence over the bike's handling, by inducing a roll moment when in motion. Example is shifting gears will move the bike a little to the left or right. So I'd guess that a BMW or Moto Guzzi wouldn't be the best bike to try to do a flip in the air, nor a wheelie. It probably would try to roll when up there.

[ReconRat]

I can't remember the builder's name' date=' but someone built a prototype with 2 crank shafts. One for the front 2 cylinders, and one for the rear. The engine sat forward to aft in the frame. The reason he split the crank was gyroscopic force. The test rider said the bike was the most responsive bike he'd ever ridden.

It plays a pretty big role, I guess. [/quote']

That would neutralize the gyroscopic moment of the engine, I think. Experiments on bicycles where extra wheels spin the opposite direction, show no bad effects on handling. Nor any effect on riding without hands. Although I think it needs more work to say what is actually happening. The gyroscopic energy is still there, but the force is altered.

[fizzer]

The video above helps explain the inertia component of the fall but leaves out the gyroscopic effects that also are in play with making the bike tip. Good video though, certainly less boring than the full explanation.

[chevysoldier]

Don't question it. It just fricken works.

[cmh_sprint]

Don't question it. It just fricken works.

+1. Why try to strip down one of the most enjoyable things you can do to the science of why it works. Accept it and smile.

[JStump]

The only argument I have is how much the crankshaft contributing to the gyroscopic effect. I'm going to say next to zero, but the rest is really good!

it actually does quite a bit, if you are ever going really slow, say moving forward in traffic after being stopped and just moving a few feet, you can rev the engine and pick your feet up even though your only going like a mile an hour or 2 but you will stay upright and wont feel like your tipping. theoretically you could rev the engine, pick up your feet and not move at all yet stay upright but i have never wanted to try that lol.

[fusion]

It's about the curvature of the tire...

[NinjaNick]

I thought it had something to do with Al Gore?

[chevysoldier]

I thought it had something to do with Al Gore?

We are talking motorcycles not global warming or the internet.

[NinjaNick]

Hey, it made me laugh and that's all that matters.

I thought about counter-steering maybe the first few times I ever rode a motorcycle and that was it.

[serpentracer]

http://www.youtube.com/watch?v=LhFtg7xM1DM&feature=channel_video_title

[chevysoldier]

Hey, it made me laugh and that's all that matters.

I thought about counter-steering maybe the first few times I ever rode a motorcycle and that was it.

Same here. I thought about it before I rode and the first couple of times. Not much after that.

[vf1000ride]

Oh come on, nobody wants to have a fun discusion about angular momentums and gyroscopic precession?

Yes the front tire must go left so you can turn right but the falling over part is really a kindergarden level explanation. You can ride a motorcycle leaned over pretty far and have it continue in a straight line if you apply the correct forces. The lean angle is not what makes a bike turn but is only a byproduct of the physics involved.

[fizzer]

Oh come on, nobody wants to have a fun discusion about angular momentums and gyroscopic precession?

Yes the front tire must go left so you can turn right but the falling over part is really a kindergarden level explanation. You can ride a motorcycle leaned over pretty far and have it continue in a straight line if you apply the correct forces. The lean angle is not what makes a bike turn but is only a byproduct of the physics involved.

Apparently we're the only ones who like to nerd out about this:D , but I can certainly agree that it doesn't really matter once you're riding because you're having so much damn fun!

[serpentracer]

Oh come on, nobody wants to have a fun discusion about angular momentums and gyroscopic precession?

Yes the front tire must go left so you can turn right but the falling over part is really a kindergarden level explanation. You can ride a motorcycle leaned over pretty far and have it continue in a straight line if you apply the correct forces. The lean angle is not what makes a bike turn but is only a byproduct of the physics involved.

technically you have to lean a bike to turn it.