A gearing system comprises a first rotational input, a second rotational input and a rotational output. The first rotational input and second rotational input may transmit a rotation to the rotational output, wherein one of the first rotational input and second rotational input is connected to the rotational output through a one way clutch, and wherein the other of the first rotational input and second rotational input is connected to the rotational output through an overrunning clutch, wherein said one way clutch and said overrunning clutch are rotationally coupled. The gearing system may be used in electric bicycles, but may also be used in other dual propulsion vehicles such as hybrid cars.