Abstract: A variable transmission automatically changing its transmission ratio in accordance with the resistance to propagation of the vehicle, in which the force-transmitting transmission link is a V-belt (1) or equivalent and in which at least the secondary pulley consists of cup disks (2,3) urged against each other and interconnected with a multiple-end screw (4,5) and a compression spring (7). As taught by the invention, the compression spring (7) is at the same time a torsion spring, and its initial position is settable at assembly or adjustable.