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01-23-2013, 03:03 PM   #266
Jedl

Joined: Jun 2010
Location: New England
Oddometer: 115
Quote:
Originally Posted by Fajita Dave
Quote:
 Originally Posted by Lion BR Man, too many words and concepts and all. You can demonstrate counter-steering by simply balancing a broom from its handle, with the handle on the palm of your hand. Move the handle (your palm) right to lean the broom left and you will go left...
It is to many words and concepts . Unfortunately there are a lot of different forces and factors that make counter steering work. If the broom example helps anyone understand why it works and gets them in the right frame of mind than stick with it! But that's not how counter steering physically works. With the broom you move your hand around under it to get the broom's CG centered back on your hand. For that to work on a motorcycle you would need to move the entire front tire left or right out from under the motorcycle the same way you move your hand under the broom (there is actually an RC bike that steers this way). On a motorcycle the front tire simply turns, it doesn't move relative to the frame other than the tiny amount caused by rake angles.
Actually Lion BR's example is a very good approximation to how countersteering affects the lean angle of a bike. Rewrite his words exchanging "contact patch" for palm and "bike" for broom and he's dead on.

Countersteering is nothing more than steering off the line that the bike is currently balanced on in an effort to move the CoG away from the current location in order to change the lean angle and affect a turn. We only countersteer (outside the turn) momentarily to initiate a turn (by moving the contact patch out allowing gravity to induce the lean), then the wheel turns towards the turn and is steering normally (during steady-state turning). When we're done turning, we again countersteer (more deeply into the turn driving the contact patches towards the CoG) to right the bike and end the turn.

Countersteering is not about keeping the front wheel turned opposite the turn during the turn. That would be foolish and would cause the bike to just lay over on it's side. Countersteering is only about changing the lean / roll angle of the bike. Once the bike is rolled into a lean, normal steering is what keeps us in balance through the turn.

The effect of countersteering is more pronounced at speed because even the slightest turn of the handlebars will see the front wheel (and it's contact patch) move quickly off to the side. It's the movement of the contact patch (like Lion BR's hand) that moves outside of the CoG (the broom) that allows the bike to lean and later turn.

Conversely, at slower speeds we have to make larger (counter) steering corrections in order to move the CoG quickly enough. That's why slow races are so difficult.

I know, I know . . too many words. And I didn't mean to science it all up like that . . . .

cheers,