Bicycle comprising a front wheel and a rear wheel, the front and rear wheels being linked by a frame, the rear wheel comprising spokes and being mounted on a rear hub, the rear hub being linked to a first drive mechanism, comprising at least one pinion mounted on a first free wheel, the pinion being able to be driven by a chain, the latter being able to be set in motion by a crankset, the bicycle comprising: - a motor, mounted on the frame; - the motor being configured to set in motion, by means of a motor shaft, a flexible transmission element; - the rear hub being linked to a second drive mechanism, that can be driven by the flexible transmission element; such that the rear wheel can be driven: - by the first drive mechanism, when the chain is set in motion by the crankset; - or by the second drive mechanism, when the flexible transmission element is actuated by the motor; - the bicycle being such that the second drive mechanism comprises a transmission crown ring secured to a second free wheel, the transmission crown ring being able to be driven in rotation by the flexible transmission element; - the second free wheel is inserted around the rear hub, such that the free wheel can drive the rear hub when the flexible transmission element drives the transmission crown ring in rotation; the bicycle being such that it comprises a brake disc, mounted on the rear hub, the second drive mechanism extending between the spokes and the brake disc, the bicycle being characterized in that the rear hub is linked to the frame by a chassis, called rear chassis, that is movable with respect to the frame and linked thereto by a damper (9.1), the motor being mounted on the frame while being immobile with respect to the frame. the bicycle comprising: - a motor, mounted on the frame; - the motor being configured to set in motion, by means of a motor shaft, a flexible transmission element; - the rear hub being linked to a second drive mechanism, that can be driven by the flexible transmission element; - a motor, mounted on the frame; - the motor being configured to set in motion, by means of a motor shaft, a flexible transmission element; - the rear hub being linked to a second drive mechanism, that can be driven by the flexible transmission element; such that the rear wheel can be driven: - by the first drive mechanism, when the chain is set in motion by the crankset; - or by the second drive mechanism, when the flexible transmission element is actuated by the motor; - the bicycle being such that the second drive mechanism comprises a transmission crown ring secured to a second free wheel, the transmission crown ring being able to be driven in rotation by the flexible transmission element; - the second free wheel is inserted around the rear hub, such that the free wheel can drive the rear hub when the flexible transmission element drives the transmission crown ring in rotation; - by the first drive mechanism, when the chain is set in motion by the crankset; - or by the second drive mechanism, when the flexible transmission element is actuated by the motor; - the bicycle being such that the second drive mechanism comprises a transmission crown ring secured to a second free wheel, the transmission crown ring being able to be driven in rotation by the flexible transmission element; - the second free wheel is inserted around the rear hub, such that the free wheel can drive the rear hub when the flexible transmission element drives the transmission crown ring in rotation; the bicycle being such that it comprises a brake disc, mounted on the rear hub, the second drive mechanism extending between the spokes and the brake disc, the bicycle being characterized in that the rear hub is linked to the frame by a chassis, called rear chassis, that is movable with respect to the frame and linked thereto by a damper (9.1), the motor being mounted on the frame while being immobile with respect to the frame.