View Single Post
Old 06-19-2013, 08:38 AM   #707
Boon Booni
Red Clay Halo
Boon Booni's Avatar
Joined: Aug 2003
Location: Richmond, Va
Oddometer: 13,917
Originally Posted by Rucksta View Post

Many staunch countersteering sceptics who have held the wheel have an epiphany.
Sometimes you can actually see the penny dropping by the expression on their faces.
Thing is if you spin the wheel really slowly the forces just are not present.

And so the argument goes round and round - just like the bicycle wheel. The faster you spin it the stronger it gets.
To me those who insist countersteering is the only way to turn a motorcyle are missing out on as much as those who instist countersteering is a myth.

Maybe my question belongs in a different thread away from the zealots and sceptics.

Here's the problem I have with saying gyroscopic procession is what leans a bike.

To start: Every action has an equal and opposite reaction. (we all know newton's third law)

So you spin the front wheel up and it balances itself in a strait line (as shown by gyroscopes spinning while only one side is supported)

You do the tire "trick" in the link you provided, spinning wheel, you turn it left it wants to lean right. Your theory, and one that I've read before on this site, is that the tendency of the spinning wheel lean right when twisted left is actually what is making the bike lean. (In fact some have said that at highway speeds the gyroscopic effect is the main force that leans the bike) So this theory works like this. You turn the bars left, the gyroscopic effect leans it right. You want to stand the bike up, from a lean right, you turn the bars right the gyroscopic effect leans it left. (am I on point?)

My problem with this is newton's third law. I read it to mean this. Back to the spinning wheel held in your hand example. You turn the spinning wheel to the left, the gyroscopic effect cause the wheel to tilt right with an equal amount of force that you applied by twisting.

If that is the case, and I'm not sure it is which is why I'm posting this. If when you turn the wheel to the right, it exerts an equal amount of force to lean, then the same thing is happening to the front wheel on your motorcycle.

You twist the bars to the left, that force is redirected by the wheel to a lean right.
If that leaning force is equal to the twisting force you applied, then an analog would be simply to pick the bike up by the bars while sitting still. With that in mind, the force I have to apply to the bars to pick the bike up from a 30 degree lean while sitting still in my garage is vastly greater than the force I need to pick the bike up from the same degree of lean while rolling down the road.

So my point is, maybe the gyroscopic effect provides some torque to the lean angle of the bike, equal to the force that I applied to the handlebars. But since the force I applied to the bars is no where near sufficient to lift the bike from it's 30 degree lean, I have to surmise that the majority of the torque is provided by the outsteering of the front wheel caused by countersteering.

My other reasoning is that turning the bars causes a moment gyroscopic torque, but that moment ends once I stop turning the bars. But my change in lean angle doesn't stop until I straiten the bars. I turn the bars a split second to the left, but hold that turn for 1/2 a second while the bike transitions from left lean to right lean. What's causing the bike to lean for the majority of that 1/2 second when I'm not actively turning the bars? IMHO it's the ousteering of the wheel, not the gyroscopic effect.

This is how I think about it anyhow, and I may be wrong..

Boon Booni screwed with this post 06-19-2013 at 08:58 AM
Boon Booni is offline   Reply With Quote