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R1_mayhem said:
couldn't have said it better myself. next time you hit a straightaway, try lightly pushing on your left OR right grip. essentially, by pushing on your right grip, you are turning the wheel so it points left, yet the bike goes to the right. that's a small example of countersteering.

leaning + countersteering = superior cornering:fact

just make sure you are at the right speed :lol

thats ur 50 cents
 
I think a good example of what tz is talking about that you can use your body to hold momment and affect, to a degree, when whatever forces you're able to store up in your body (from the bike) are transfered back to the bike.
It's the same total force but it can be applied at different times and potentially over a longer period that it would be if you didn't move your body at all.
An upright example of this is lifting your ass off the seat so you don't get knocked as hard on bumps -- your suspention doesn't compress as far, absorbs less energy (which it needs to put out again) and doesn't travel as far to get back to its regular extension.

The total change in mommentum (force * time) is the same from whatever time you see the bump until you get back in normal riding position (total should be zero), whether your butt gets launched or you pick it up beforehand yourself. The only difference is the intensity of the force and, due to the involvement of the suspension, the total number of transers back and fourth.

You can use the mass of your body to enhance the 'smootheness' (absorb peaks), as well as to prevent suspension bounce.

When making little swerves around manhole covers in the road, I shift my weight to setup because makes it 'feel' easier.
 
heatmizr said:
Hmmmmm....... I'm not buying it.
Whether you have a force of 5 over 10 seconds (total=50) or a force of 50 over 1 second (total=50) it is the SAME total force, and should have an equal effect. This is really just math after all.
You're right that it's just math, but you need to be doing the *right* math. It isn't the total force that matters in this case; it's the peak force. In other words, the force you apply to the bike has to be great enough to make it do something.

If you had a center stand on your bike and you were sitting in the saddle, would it be possible for you to hang off to one side without disturbing the bike?

Once you were hanging off, would it be possible to tip the bike over (or at least rock it) by pulling suddenly with your knee against the tank?

If you see that the answer to the two questions above is "yes," then the math that explains how this is possible will also illustrate my earlier point.

ab
 
Thinking about the above post a bit more, consider the force it takes to lift a 50 pound weight off the floor: It takes a little more than 50 pounds of force to lift 50 pounds.

In a world where heatmizr's last comment above is true, I could lift a 50 pound weight by applying 10 pounds of force five times. Sometimes I wish that were the case here on Earth, but in my experience it's not.

ab
 
tzrider said:
Great point easy, though it might be useful to distinguish between a couple of kinds of stability:

1) A bike's resistance to changing lean angle
2) A bike's tendency to remain in balance in a straight line

In your example of a ski-bike, the front ski would have to have a configuration that mimics trail on a motorcycle. One possibility is the attachment point for the front ski is somewhere in the front of center on the ski, so the ski tracks the way an arrow would. In this case, the ski would tend to re-center itself as you hit small irregularities on the snow. Your motorcycle does the same thing via trail on the front wheel. Inertia does indeed keep the bike going in a straight line and trail keeps the front wheel tracking.

Reportedly (I haven't ridden one), a ski-bike countersteers. It makes sense, as the thing should behave similarly to a motorcycle in that you create a lean angle change by steering the wheels (skis) out from under the bike. Steer the ski to the left and the bike tips to the right.

You'll encounter a little resistance to your countersteering from the trail of the wheel (or ski), but most resistance to a countersteering input will come from the inertia of the gyro (front wheel). The bike has some resistance to lean angle change from the gyroscopic inertia of both wheels, but this won't affect the feel at the bars to the same extent that the front wheel does. In other words, if you have a heavy front wheel and a light rear, the bike will steer heavier than if you have a light front and heavy rear.

To heatmizr's point, the key is in how much energy you put into the bike in a particular moment in time. Let's say you're sitting square in the saddle and decide to hang off to the right. From side to side, your body has no momentum before you begin moving. Then, consider that:

Momentum = Force * Time.

To get your body moving across the bike, you may press with a few pounds' force over a period of a second or two. This won't be enough to change the bike's lean angle noticably, because of the wheels' gyroscopic inertia. Once your body is moving, it has momentum. Now, consider that:

Force = Momentum / Time

If, as you reach the hangoff position to the right, you suddenly pull on the tank with your left knee, you have your body's momentum applied to the tank in a fraction of the time it took to create the momentum. If it took you a second to move across the bike using constant pressure and then you release your momentum into the bike's chassis in a tenth of a second, you will transmit a peak force into the bike ten times greater than the peak force you applied to the bike as you were moving accross it.

In that instant, this peak force may be enough to overcome the wheels' gyroscopic inertia where the force you applied over a longer period to get your body moving was not.

ab
Strictly speaking, momentum is mass * velocity. You can derive your momentum equation from that (using Newton's F=mA) but then you are into impulses, for which you need a change in velocity.

I don't think that you can just "release your momentum into the bike's chassis." How do you do that? The peak force you transmit into the bike is just that-how much you can push or pull on things.

I think you're on the right track in one respect. As you move across the bike, you are moving slow, with a low force into the bars/pegs/tank. This will have little effect on the bike if you consider your momentum and acceleration. When you want to move the bike, you use as much force as you can, and move as fast as you can. This has both momentum and acceleration effects on the bike.

AT
 
Andrew Trevitt said:
I don't think that you can just "release your momentum into the bike's chassis." How do you do that? The peak force you transmit into the bike is just that-how much you can push or pull on things.
I probably chose my words poorly above. What I am trying to convey is that you can begin moving your body slowly and gradually accelerate it from one side of the bike to the other without disturbing the bike much, if at all.

Once your body is in motion, you can use its abrupt impact against the side of the bike to deflect the bike's lean angle some.

I may not be doing a great job of explaining how this can be, but I have demonstrated it several times in real life on the No-BS bike. I'm the only person I know of who has weaved a set of cones on the bike without falling off or knocking cones over.

BTW, this would be a good place for me to say that I don't recommend trying to steer your bike in this fashion. It's teribly inefficient, inaccurate and I think costs more attention and energy than it's worth. When I'm riding for real, I countersteer and keep my body as still as possible during the lean angle change. For me, trying to steer a bike with my body has no practical application. I took the trouble to learn to "bodysteer" the No-BS because I got tired of hearing from bodysteering guys that I held the opinion I did because I don't know how to bodysteer. At this point, I can bodysteer the bike to greater effect than anyone else who has tried it and I still consider bodysteering little better than a curiosity.

Originally posted by Andrew Trevitt
I think you're on the right track in one respect. As you move across the bike, you are moving slow, with a low force into the bars/pegs/tank. This will have little effect on the bike if you consider your momentum and acceleration. When you want to move the bike, you use as much force as you can, and move as fast as you can. This has both momentum and acceleration effects on the bike.
Yes. The combination of moving comparatively slowly to get into a hang-off position, impacting the bike as you arrive at the hang-off position and pulling hard and quickly against the bike at the moment you impact it can cause a lean angle change. You'd probably find that your body and the bike would each move toward a point in between the two, equal and opposite reaction being what it is. The use of your momentum to impact the bike does allow you to create more lean angle change than just yanking on the bike from a static hangoff position would.

ab
 
tzrider,
you know, this has been going on so long that i may have to go back and reread parts of this thread, to get my head back into it.
though i see what you are saying in the above examples, a couple of points you are making just don't feel right to me, and seem to go against basic physics principles (you know, energy cannot be destroyed/absorbed without *something* happening as a result), but i may have to do more research to be able to appropriately/correctly put into words what i am getting at.
for example, i don't think you can compare a bike on the centerstand to a bike that is balancing in equilibrium.

anyway, maybe i will be back with some more useful scientific hoo-ha....
 
heatmizr said:

though i see what you are saying in the above examples, a couple of points you are making just don't feel right to me, and seem to go against basic physics principles (you know, energy cannot be destroyed/absorbed without *something* happening as a result)
You're right that energy cannot be destroyed; it can only be converted. If you press against a cinderblock wall with a force of ten pounds, what does that force get converted into? The wall probably won't move; part of the force you apply may move your body and some of the energy will be converted to heat.

Remember that objects under enormous pressure create a lot of heat -- this is the same thing at work; the conversion of kinetic energy into heat.

You're right that comparing a moving motorcycle to one on a centerstand is often useless, though in this case it isn't. A motorcycle in motion isn't a delicately balanced thing; it's quite stable. If anything, the bike on the sidestand is less stable, yet you can perform the demonstration I described earlier. You can move from one side to the other without visibly disrupting the bike. You can also probably pull hard enough to tip the bike over.

ab
 
This is an old thread......

So much has changed in physics now. Scrape everything you think you know because countersteer is no longer "in style". Body steer is the only way to go. Here is a pic of the new technique in action.....



photo courtesy of "the Hooligan's"
 

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If it helps TZ, I understood everything.

Moving quickly off the bike will lean the bike more due to the sudden stop.(same reason you drive a nail with a hammer instead of pushing it in) These types of movements are not very precise. This would require even better counter steering skills to compensate.

You need to move around on the bike like you have a cup of hot coffee. If you move abruptly your going to spill it, along with upsetting the bike.
 
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GXRKLR said:
You need to move around on the bike like you have a cup of hot coffee. If you move abruptly your going to spill it, along with upsetting the bike.
What's interesting about this is that it is possible to move from one side of the bike to the other *extremely* quickly without disturbing the bike much. When we're riding at real speeds on real racetracks, our body movements have even less effect than they do when we're fooling around at low speeds.

A perfect example is a fast left-to-right transition, such as that in the corkscrew at Laguna. You want to get from the left side of the bike to the right in a hurry and it's not hard to do that without disturbing the bike much. One difference is that you're initiating the movement and arresting it at roughly the same speed, so the inputs you give the bike wil mostly cancel each other out. The bike may wiggle a small amount (if you do it roughly), but the lean angle will be pretty steady until you push the bars.

ab
 
tzrider said:
I took the trouble to learn to "bodysteer" the No-BS because I got tired of hearing from bodysteering guys that I held the opinion I did because I don't know how to bodysteer. At this point, I can bodysteer the bike to greater effect than anyone else who has tried it.
Yea, well I can crash the no-BS bike with a greater effect than anyone else who has tried it (or at least has tried it, and will admit it). :)
 
tzrider said:
What's interesting about this is that it is possible to move from one side of the bike to the other *extremely* quickly without disturbing the bike much. When we're riding at real speeds on real racetracks, our body movements have even less effect than they do when we're fooling around at low speeds.

A perfect example is a fast left-to-right transition, such as that in the corkscrew at Laguna. You want to get from the left side of the bike to the right in a hurry and it's not hard to do that without disturbing the bike much. One difference is that you're initiating the movement and arresting it at roughly the same speed, so the inputs you give the bike wil mostly cancel each other out. The bike may wiggle a small amount (if you do it roughly), but the lean angle will be pretty steady until you push the bars.

ab
Hi TZrider
I don't see how you can move your body from one side of the bike to the other with the same lean angle, not gana happen. If your body moves the lean angle or the radius of the track will change. To keep the same track you will be counter steering as you move I.E. more lean angle.:2bitchsla
 
Balistic said:
Hi TZrider
I don't see how you can move your body from one side of the bike to the other with the same lean angle, not gana happen. If your body moves the lean angle or the radius of the track will change. To keep the same track you will be counter steering as you move I.E. more lean angle.
So, are you saying that moving your body on the bike is an effective way to cause a lean angle change? :p

I don't think I said the bike's lean angle won't change at all; I thought I said it wouldn't change much. Do you disagree?

ab
 
tzrider said:
So, are you saying that moving your body on the bike is an effective way to cause a lean angle change? :p

I don't think I said the bike's lean angle won't change at all; I thought I said it wouldn't change much. Do you disagree?

ab
Hi tzrider
So I guessing that you have labled me as a bs opponent. Not so. I do know what it is and when it can be used and for what purpose, My oppinion of corse.
I am saying if you move the CG the bike will react with lean angle.
What you said was "but the angle will be pretty steady until you push the bars". This is what I take issue with. If you move the CG the amount of your body from one side to the other the bike will react. You can suppress this reaction with steering the bike deaper into the corner as you move over and then do the steering for the next turn. If you don't when the CG moves the lean angle will change and the steering will have started with the body movment perhaps earlier than you wanted.
Please no math, I am just a guy who rides with some understanding of how these here bike work dynamicaly not theoreticaly.;)
 
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