The hydraulic speed-changing bicycle includes a driving system formed from pedals, oil pump, oil circuit board, non-return valve, pressure oil pipe, hydraulic control valve, left and right connectors, oil motor and oil-returning pipe, a brake system formed from left brake bar, cam, plunger pump, oil deflector pipe, oil cylinder, brake clamp, brake rubber and non-return valve, an oil-supplementing system formed from oil-storing vertical pipe, pressure-increasing pipe and air-exhausting cock, a bicycle body and its accessories. Said invention is reasonable in structure, fase and realiable, can raise bicycle speed, can automatically regulate flow rate and pressure relationship, so that it is optimum substituted for motorcycle and electric bicycle. |