A continuously-variable-ratio transmission (CVT) of the toroidal-race rolling-traction type, capable of operating in 'low' and 'high' regimes with synchronous change between those regimes, and including a variator (3) - that is to say a ratio-varying component - and an associated gearing set (2) of which the components are capable of being set in different combinations for the high and low regimes, in which the output of the gearing is connectable to the output (1) of the CVT as a whole, and the gearing has first (25) and second (29) inputs connected with the variator output (19) and engine output (5) respectively, and in which in low regime the gearing is set to recirculate power and so deliver to its output a power equal to the difference between its two input powers, whereas in high regime it is set so as to split the power flow and to deliver to its output a power representing the sum of the powers at its two inputs.