Wire wheel 6 rigid spokes began to appear in the Olympic Games and professional racing: these have advantages in specialized applications, such as time trials, but wire-spoked wheels are used for most purposes. The reaction to a radial load of a well-tensioned wire spoked wheel, such as by a rider sitting on a bicycle, is that the wheel flattens slightly near the ground contact area. The rest of the wheel remains approximately circular. The tension of all the spokes does not increase significantly. Instead, only the spokes directly under the hub decrease their tension. The issue of how best to describe this
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