A transmission is disclosed for a wheeled vehicle. The transmission has a rotary input (14) to be driven by a rotary power source, e.g. an internal combustion engine. It has a rotary output (16) for driving a vehicle wheel. A transmission unit is coupled between the rotary input and the rotary output to transfer drive between them at a speed ratio which is continuously variable through a range which includes both negative ratios (providing a reversal of rotational direction between the rotary input and the rotary output), positive ratios (in which the rotary input and the rotary output rotate in the same direction), and a geared neutral ratio, in which the rotary output is stationary. In accordance with the invention, the transmission further comprises a brake (20) for braking the rotary output. The brake is provided with a control arrangement adapted to apply it when the speed ratio is set to the geared neutral ratio and to release the brake as the speed ratio is adjusted away from the geared neutral ratio.