best explanation of counter-steering I've heard

[SWing'R]

Don't question it. It just fricken works.

[ducati guy]

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']

+1. There was a show on HD Theater about this. The guy was building a moto gp bike.

[jarvismb]

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']

+1. There was a show on HD Theater about this. The guy was building a moto gp bike.

The company is MotoCzysz.

The bike you're talking about is the C1, but they seem to have abandoned it after 2008. They're doing crazy things in the electric race bike world now, instead.

[jporter12]

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.

Are we confusing torque with gyroscopic forces in this case?

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.

I've never noticed any difference in this sort of situation from revving the engine, but I HAVE noticed a difference with a little bit of clutch applied, to keep the power to the tire, which only adds confusion to the discussion!

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.

A NECESSARY "byproduct" of the physics involved.

technically you have to lean a bike to turn it.

But, you CAN lean a bike without turning it. Maybe not by a huge amount, but you can.

Put your hands on the tank and try to turn with JUST leaning. You will turn, but it won't be nearly as much as expected.

Dis claimer: I'm not advocating riding with your hands off the controls, find a closed course to do so. Doing so on the street or highway is not a good idea, even if most of us have taken our hands off the controls just to prove to ourselves that we can.

[jporter12]

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']

Were the engines turning the same direction? I would think that it would be more a product of the rotating MASS than anything. The ironic thing about that is that engine builders, and I would imagine the OE try to reduce rotating mass to make higher revving engines with more power output.

If the engines were running in opposite directions, I would think they would cancel each other out. If that's the case, there would be less gyro effect to overcome making the bike more responsive. Just thinking aloud here...

[Disclaimer]

Don't question it. It just fricken works.

This is still the best post so far.

You can discuss it, and there's nothing wrong with learning and understanding the science/physics behind it, but when it comes to executing it -- you either do or don't. You don't think about it. It's reflexive. Muscle memory through riding experience.

[jarvismb]

Put your math hats on, kids, we're gonna play nerd...

In layman's terms, this whole thing is all just a clusterfuck of cross-products, but it's that multi-vector gangbang that makes the bike lean over when you countersteer.

Think about however is best for you, but realize that it's the cross-products of angular momentum that is doing all the work here. For simplicity's sake, let's ignore the engine effects, and concentrate on the front wheel....

Here's the big picture of why this works:

Now, all this is saying is that the wheel's spin about the z-axis is directly related to its moments about the other two axes as well (nutation and precession). In this plot, the spin would make the wheel precess about the y axis. In a motorcycle, there are two front forks, so there is a shaft on both sides (modeled here as R), thereby making a system with zero precession when spinning with no other inputs.

Now here's the important part - since the cross-products are always related, if you introduce precession (by turning the handlebars), you must also introduce nutation along the x-axis. The wheel will want to fall over to the side. This moment will be induced along the center of mass, but since the bottom of the wheel has a tire on it with a lot of friction, it just tips the whole thing over, along with the bike and rider that are attached to it.

It's really not that crazy, it's just that people don't normally come across this kind of stuff in everyday conversation, so most people don't get a real explanation of it, so sometimes it can be made out to seem more complicated than it is.

Hope that helps, and any of my fellow engineers can chime in a correct me if I've used improper nomenclature

[JBWalker]

if you can walk, you can counter-steer.

[redkow97]

I agree with "don't question it," I was just impressed with an easy-to-understand explanation using the stick.

The full physics are a lot more complicated, but the basic concept isn't.

There's a guy testing/patenting reverse rotating brake rotors as well. He claims it will eliminate a lot of instability. http://www.reverserotatingrotors.com/

In theory, I hear where he's coming from, but if there was that much to his idea, I would have to think the big 4 (plus Ducati, Aprilia, etc.) would be knocking down his door trying to buy the technology.

[Disclaimer]

...I post enginerd stuff...

Hope that helps, and any of my fellow engineers can chime in a correct me if I've used improper nomenclature

I never had to take dynamics so, I'll go ahead and assume your nomenclature is ok. Right-hand-rule!

[cd0583]

like a bicycle..if you're riding straight ..turn the bars right the bike will fall left