Abstract: A stepless speed change gear for bicycles and the like. A device is disclosed wherein a rotary input is converted to reciprocating motion by a rack and pinion, the rack is mounted at the end of a lever which is oscillated; an arm is mounted on the lever, connecting it to a rod which is driven in alternating rotary directions; the rod is connected to the output shaft by two ratchets driven in alternate directions by said rod, said ratches are geared to said output shaft in such a way that the output is a continuous rotary motion. The speed change mechanism being that said arm is slidably mounted on said lever and rod so that the nearer the arm is drawn to the end of the lever on which said rack is mounted the greater is the oscillating motion imparted and the greater is the subsequent angle through which the rod is rotated.