Originally Posted by F1_Fan
I might be wrong (having never really ridden a motorcycle) but I always thought the fact that you could use the throttle to balance the bike through a corner meant that the same rules didn't apply to bicycles.
The mid-corner dynamics are different. But initiating a turn is the same between the two. Counter-steering is more apparent on a motorcycle because you have have more bike weight and more rotational mass to influence when changing directions. margoC is really going to notice it on his Vstar because it's a big, heavy bike with a long wheelbase and relaxed steering geometry. Sportbike riders will notice it less because they're lighter, shorter, and steeper in the geometry department. (It's like comparing a Rivendell touring bike to a Biachi EV4...)
But two fundamental differences make motorcycles behave differently mid-corner: Weight distribution and unequal tire sizes (between front and rear).
To get a motorcycle to continue to steer from the apex you need to roll-on the throttle. It's less about actually balancing the bike and more about controlling turning rate and regulating traction.
Originally Posted by F1_Fan
I've been playing with the "counter-steering" thing this week and I've come to a conclusion. Pushing down on the inside bar simply makes the wheel turn a slightly tighter arc, that forces you to lean slightly more and (you have to) go faster through the corner so you don't fall. The push/lean cycle continues in imperceptible amounts until you find the desired turning radius.
Pushing down on the inside bar to tighten-up your turning radius is actually a counter-steering input. Once you're in a turn and the bike is at neutral (going in a circle) it takes an additional counter-steering input to make the bike do something different, in this case, to turn tighter. (To return to straight line travel, you push down on the outside bar... Which is still a counter-steering action.)
If you stand over your bike with your feet on the ground and your hands on the bar, push down with your right hand as you would while riding. You'll see that the wheel went to the left.
The mechanics of this is that while your arm is pushing down, it's also extending. Since you're situated behind the bar (and its steering axis), this arm extension pushes the inside bar away from you. Voila, counter-steering.
And just to tie this discussion into the other one about fork rate and bike geometry, a moving bicycle wants to go straight really, really badly! It's the monkee that's squirming around in the seat that throws everything off!
-Erik