The longitudinal placement of the engine, most of its mass positioned ahead of the front wheels, allowed the R12 to have a very simple design of the gear-selector that was placed on the floor of the car, and not on the dashboard as with the R4 or on the steering column as with the R16. On the early cars the handle to operate the handbrake was placed under the dashboard. The handbrake was later relocated to a position between the two front seats.