A transmission system, especially for use in automobile vehicles, in which the ratio-varying unit is of the continuously-variable type particularly the toroidal-race rolling traction type. An epicyclic combination is located between the ratio-varying unit output and the final output of the system as a whole. In reverse drive a band brake is engaged to arrest the epicyclic planet carrier so that the unit output and final output are connected by way of the epicyclic gearing, and an epicyclic ratio of substantially greater than 1:1 promotes proper speed limitation in reverse drive. In forward drive the brake is disengaged but a friction clutch is engaged to connect the unit output directly to the final output. By their progressive action the brake and clutch enable the transmission to start from rest in either forward or reverse drive, without the need for separate friction clutches.