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Difference between revisions of "Counter steering"
→How it works
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A single-track vehicle such as a bicycle or a motorcycle is an inverted pendulum—it will fall over unless balanced. | A single-track vehicle such as a bicycle or a motorcycle is an inverted pendulum—it will fall over unless balanced. | ||
The technique used by cyclists and [[Motorcycling|motorcyclists]] to initiate turning in a given direction is to first apply a steering torque in the opposite direction. For example, if a turn to the left is desired, it is started by a turn of the handlebars to the right. Under this force the front wheel will rotate to turn right and the front tire will generate forces to the right. The machine as a whole steers to the right briefly and the rear tire also generates forces to the right. Because the forces are applied at ground level, this pulls the wheels "out from under" the motorcycle and to its right. The resulting roll angle to the left causes the tires to then generate camber thrust to the left providing the | The technique used by cyclists and [[Motorcycling|motorcyclists]] to initiate turning in a given direction is to first apply a steering torque in the opposite direction. For example, if a turn to the left is desired, it is started by a turn of the handlebars to the right. Under this force the front wheel will rotate to turn right and the front tire will generate forces to the right. The machine as a whole steers to the right briefly and the rear tire also generates forces to the right. Because the forces are applied at ground level, this pulls the wheels "out from under" the motorcycle and to its right. The resulting roll angle to the left causes the tires to then generate camber thrust to the left providing the centripetal forces required to turn left. The geometry of the steering system provides the forces necessary for the front wheel to adopt an angle turned into the turn in a conventional manner<ref>{{cite web | ||
| url = http://www.phys.lsu.edu/faculty/gonzalez/Teaching/Phys7221/vol59no9p51_56.pdf | | url = http://www.phys.lsu.edu/faculty/gonzalez/Teaching/Phys7221/vol59no9p51_56.pdf | ||
| first = David | | first = David | ||
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It is often claimed that two-wheeled vehicles can be steered using only weight shifts. While this is true for small "trim" inputs to direction, complex maneuvers are not possible using weightshifting alone because even for a light machine there is insufficient control authority.<ref name="evangelou">Evangelou, S, 2004 "The Control and Stability Analysis of Two-Wheeled Road Vehicles", PhD Thesis, Imperial College London</ref> | It is often claimed that two-wheeled vehicles can be steered using only weight shifts. While this is true for small "trim" inputs to direction, complex maneuvers are not possible using weightshifting alone because even for a light machine there is insufficient control authority.<ref name="evangelou">Evangelou, S, 2004 "The Control and Stability Analysis of Two-Wheeled Road Vehicles", PhD Thesis, Imperial College London</ref> | ||
Although on a sufficiently light bike (especially a | Although on a sufficiently light bike (especially a bicycle), the rider can initiate a lean and turn by shifting body weight,<ref name="fajans"/>, there is no evidence that complex maneuvers can be performed by bodyweight alone | ||
<ref name="code"/>. | <ref name="code"/>. | ||
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The reason this no-hands steering is less effective on heavy bikes, such as motorcycles, is that the rider weighs so much less than the bike that leaning the torso with respect to the bike does not cause the bike to lean far enough to generate anything but the shallowest turns. No-hands riders may be able to keep a heavy bike centered in a lane and negotiate shallow highway turns, but not much else. | The reason this no-hands steering is less effective on heavy bikes, such as motorcycles, is that the rider weighs so much less than the bike that leaning the torso with respect to the bike does not cause the bike to lean far enough to generate anything but the shallowest turns. No-hands riders may be able to keep a heavy bike centered in a lane and negotiate shallow highway turns, but not much else. | ||
==Motorcycles== | ==Motorcycles== | ||