Abstract: The invention resides in an infinitely variable traction roller transmission with coaxial input and output shafts, a main transmission shaft rotatably supported in spaced parallel relationship with the input and output shafts and with an input traction roller drive interconnecting the input shaft and the main shaft and further an infinitely variable traction roller transmission structure disposed on the main shaft for transmitting motion from the main shaft at variable relative speed to the output shaft via an output traction roller drive wherein the input and output traction roller drives include traction gears mounted in radial alignment respectively on the input shaft and the main shaft and an output shaft of he infinitely variable traction roller transmission and hollow shaft surrounding the input shaft and connected to one of the ring and the planet carrier of a planetary-type transmission whose other of the ring and planet carrier is connected to the output shaft and whose sun is disposed on the input s