Mono Posted January 7, 2017 Share Posted January 7, 2017 3 minutes ago, Chris Westland said: Two-wheelers stay up because of the gyro torque of the front wheel and the anchor provided by the frame/rear wheel. Uni- and bicycles remain upright because the contact point is constantly steered under the centre of gravity. Gyroscopic forces contribute to inertia and possibly to steering, but they do not keep the vehicle upright in themselves. If the steering is fixed bicycles won't stay upright. A bicycle built such that gyroscopic forces cancel remains perfectly ridable. A general design goal for two-wheelers is to make the wheel as light as possible. This also minimises gyroscopic forces, but this is never a concern of designers. If gyroscopic force were the central mechanism to keep the vehicle upright, it seems we would really want to make sure the wheels are heavy enough, but we don't, and vehicles with heavy wheels should be easier to keep upright, but they are not, arguably rather the opposite. As you know all this already I guess we will nevertheless remain in disagreement here Link to comment Share on other sites More sharing options...
Chris Westland Posted January 7, 2017 Share Posted January 7, 2017 7 hours ago, Mono said: Uni- and bicycles remain upright because the contact point is constantly steered under the centre of gravity. Gyroscopic forces contribute to inertia and possibly to steering, but they do not keep the vehicle upright in themselves. If the steering is fixed bicycles won't stay upright. A bicycle built such that gyroscopic forces cancel remains perfectly ridable. A general design goal for two-wheelers is to make the wheel as light as possible. This also minimises gyroscopic forces, but this is never a concern of designers. If gyroscopic force were the central mechanism to keep the vehicle upright, it seems we would really want to make sure the wheels are heavy enough, but we don't, and vehicles with heavy wheels should be easier to keep upright, but they are not, arguably rather the opposite. As you know all this already I guess we will nevertheless remain in disagreement here On the contrary, I generally agree, and this makes sense, that while the motorbike is at speed = 0 (still) it must be balancing by shifting the contact patch left and right underneath the CoG. The gyro forces are a significant part of stabilization and steering when at speed, and are more important with heavier bikes (i.e., motorbikes); they are why you countersteer and the reason that 2-wheelers stay upright when traveling forward. With 150 free parameters there is obviously a lot more going on here and one parameter (angular momentum) won't do it all. At at these very low speeds, gyroscopic forces are small or not important at all. Link to comment Share on other sites More sharing options...
abinder3 Posted January 8, 2017 Share Posted January 8, 2017 14 hours ago, Chris Westland said: Best done on a track, IMHO ... I do it in corners (partly because it looks cool, partly it's good form). But the worry is that you catch your knee puck on the rumble strip, or in the street ... who knows what. The really cool riders put titanium screws in their knee pucks... I was talking about self balancing not for motorcycles. Link to comment Share on other sites More sharing options...
abinder3 Posted January 8, 2017 Share Posted January 8, 2017 5 hours ago, Chris Westland said: I generally agree, except the gyro forces are a significant part of stabilization and steering; they are why you countersteer and a bit part of why 2-wheelers stay upright. With 150 free parameters there is obviously a lot more going on here and one parameter (angular momentum) won't do it all. You don't have to counter steer to corner on a motorcycle. I never counter steer and there have been studies that suggest that counter steering is what gets people in trouble on motorcycles. Link to comment Share on other sites More sharing options...
Mono Posted January 8, 2017 Share Posted January 8, 2017 8 hours ago, abinder3 said: I never counter steer and there have been studies that suggest that counter steering is what gets people in trouble on motorcycles. I would be interested to have a look at these studies. AFAIK, counter steering is the only reliably controlled method to drive a curve. We all counter steer when riding a motorbike, but most of us never thought about it and don't do it consciously. Trying to do it consciously might lead to unexpected results and hence into trouble. Link to comment Share on other sites More sharing options...
Frode Posted January 9, 2017 Share Posted January 9, 2017 19 hours ago, Mono said: AFAIK, counter steering is the only reliably controlled method to drive a curve. You are correct. 19 hours ago, Mono said: Trying to do it consciously might lead to unexpected results and hence into trouble. I have never ever experienced this. On the contrary, consciously counter steering has brought me out of dangerous situations (entering corner with to high speed, and also avoiding hitting a car crossing my road without seing me) Link to comment Share on other sites More sharing options...
Smoother Posted January 9, 2017 Share Posted January 9, 2017 If by counter steering your as referring to turning the handlebars in the opposite direction to the desired direction, then I see both sides of this discussion. I've been riding motorcycles, on and off for 40 years. I admit, that when simply riding, I do not notice any tendency on my part to counter steer; I lean I turn. However, I have experimented with counter steering while riding straight ahead, and noticed that if I pull the bars left, the bike leans and turns right, and vice Verse. I guess when you pull the contact point of the front wheel to one side the weight of the bike is now on the other side, so it drops that way. Also, sometimes in a corner, I have had reason to adjust my line ( in order to avoid a wet man hole cover for example) and tugging the bars one way produces the desired adjustment in the other direction. I have no reason to doubt that these forces are being applied subconsciously during normal turning, but so subtly, that the rider is not even aware of it. Link to comment Share on other sites More sharing options...
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