Sunday, June 26, 2011

Counter Intuitive Steering

To understand counter steering, remove the front wheel of a ten speed bicycle. Grab both ends of the axle and roll the tire across the ground fast enough to keep the wheel spinning. Now try to turn the wheel to the left. What happens is the wheel turns right, the opposite way you wanted it to turn. This is the result of counter steering and whether you know it or not you've been counter steering every motorcycle and bicycle you've ever ridden since you were old enough to go over seven miles per hour.

Speed is important because as your wheels turn faster and faster they begin acting like gyroscopes that want to keep moving in the same direction. To get your wheels to deviate from that direction they need to be tricked into doing so. We accomplish deception through counter steering. If you temporarily deflect the wheel in the opposite direction of a turn, the wheel tries to center itself again but overcompensates and continues past the center point and starts to turn in the direction you originally intended for it to turn. The common phrase is "push left, go left. Push right, go right" While the rider is the heaviest part of a bicycle and can initiate a turn by the rider shifting their weight to the inside, motorcycles are far heavier and the rider makes up only a fraction of the total weight of the motorcycle and rider. Therefore, a motorcycle rider cannot initiate a turn at high speeds using only a shift in weight because this alone will not overcome the gyroscopic effects of the wheels, flywheel, crankshaft, alternator and etcetera. The fastest way to coax a motorcycle into changing directions at speed is to steer in the opposite direction of your intended turn.

While the physics behind counter steering are far from intuitive all it takes is a bicycle and an empty street to see how commonplace this phenomenon really is. Ride a bicycle in a straight line at a speed fast enough to take your hands off the handlebars. If you can't do this remove one hand and use the other to hold the handlebars in the middle, overtop the gooseneck. Take the free hand and push the left handlebar forward and release. The bike will temporarily veer to the right followed by a quick left turn, relative to your speed and the force with which you hit the handlebar. Experiment at faster speeds and pushing the handlebar progressively harder until you get a grasp of the phenomenon and feel comfortable applying this to your motorcycle riding. Counter steering is relevant to motorcycling because it allows rider to steer a motorcycle with greater efficiency and in less time than any other steering input. Whether you are pitched over in a turn when you spot a hazard that needs to be avoided or turning down the street you live on, counter steering will get you there safer and turning in less time than it takes to say "push left, go left."


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