But there is a third motion that isn’t talked about much. Though there are springs inside the fork, the fork itself is also a spring. It allows the axle to move back and forth, perpendicular to the fork’s sliding axis (and, to a lesser extent, side-to-side), because the fork tubes flex under load, bending as load conditions change. And this flexing and recovering motion is not damped. The extent of flex is controlled by the strength of the components, but the movement itself is not controlled.