Bicycle wheel to counteract the leading spokes. When forward torque is applied (i.e., during acceleration ), the trailing spokes experience a higher tension, while leading spokes are relieved, thus forcing the rim to rotate. While braking, leading spokes tighten and trailing spokes are relieved. The wheel can thus transfer the hub torque in either direction with the least amount of change in spoke tension, allowing the wheel to stay true while torque is applied. Wheels that are not required to transfer any significant amount of torque from the hub to the rim are often laced radially. Here, the spokes leave the hub
Idler-wheel sees this on true tracked vehicles, however, as the second drive wheel is redundant. Idler-wheel An idler-wheel is wheel which serves only to transmit rotation from one shaft to another, in applications where it is undesirable to connect them directly. For example, connecting a motor to the platter of a phonograph, or the crankshaft-to-camshaft gear train of an automobile. Because it does no work itself, it is called an "idler". An idler-wheel may be used as part of a friction drive mechanism. For example, to connect a metal motor shaft to a metal platter without gear noise, early phonographs used