legs or in the torso that causes the bike itself to lean to the right. The combined center of mass of the bike and rider is only lowered and not moved out, but if the front of the bike is free to swivel about its steering axis, the lean to the right will cause it to steer to the right by some combination of gyroscopic precession, ground reaction forces, gravitational force on an off-axis center of mass or simply the inertia of an off-axis center of mass depending on the exact geometry and mass distribution of the particular bike and the amount of torque and the speed at which it is applied. This countersteering to the right causes the ground contact to move to the right of the center of mass, as the bike moves forward, thus generating a leftward lean. Finally the front end steers to the left and the bike enters the left turn. The amount of leftward steering necessary to balance the leftward lean appropriate for the forward speed and radius of the turn is controlled by the torque generated by the rider, again either at the seat or in the torso. To straighten back out of the turn, the rider simply reverses the procedure for entering it: cause the bike to lean farther to the left; this causes it to steer farther to the left, which moves the wheel contact patches farther to the left, eventually reducing the leftward lean and exiting the turn. A National Highway Traffic Safety Administration study showed that rider lean has a larger influence on a lighter motorcycle than a heavier one, which helps explain why no-hands steering is less effective on heavy motorcycles. 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. Complex maneuvers are not possible using weightshifting alone because even for a light machine there is insufficient control authority. Although on a sufficiently light bike (especially a bicycle), the rider can initiate a lean and turn by shifting body weight, there is no evidence that complex maneuvers can be performed by bodyweight alone. Other uses The term countersteering is also used by some authors to refer to the need on