The present invention discloses a three-stage bicycle transmission and a bicycle, relating to the technical field of bicycles, including a
speed regulator disposed on the handlebar and a speed-changing piece on the vehicle body. The
speed regulator and the speed-changing piece are connected by a speed-changing wire. It includes a three-stage transmission, and the three-stage transmission includes a gear-changing disc, a low-speed chain wheel, a medium-speed chain wheel, a high-speed chain wheel and a
crank which are sequentially combined in order. The low-speed chain wheel is fixedly connected to the
crank, and the medium-speed chain wheel and the high-speed chain wheel are connected to the
crank through bearings. The low-speed chain wheel, the medium-speed chain wheel and the high-speed chain wheel are respectively and independently connected with a chain. A linkage mechanism is provided on the crank, and a gear-changing mechanism is provided on the gear-changing disc. In the present invention, the low-speed chain wheel, the medium-speed chain wheel and the high-speed chain wheel respectively drive their own chains, and the gear-changing disc controls the gear shifting. The gear shifting is smooth and easy, with a 360-degree dead-free angle, and the chain will not be shifted to cause chain
derailment. Moreover, all internal parts are realized through mechanical structures and do not involve any electronic devices, so the production and manufacturing cost is low.