Outer variable speed bicycle

The utility model discloses an external variable speed bicycle which comprises a bicycle frame and a cushion fixedly connected to the top end of the bicycle frame, a fixing sleeve is fixedly connected to the peripheral face of the top end of the bicycle frame located on the lower side of the cushion in a sleeved mode, a winding box is fixedly connected to the right side face of the fixing sleeve, and a winding roller is elastically and rotationally connected to the interior of the winding box. A waterproof film is connected to the peripheral face of the winding roller in a coiled mode, one end of the waterproof film is fixedly connected with a connecting block, and the upper surface and the lower surface of the connecting block are each fixedly connected with a clamp. When the bicycle disclosed by the utility model is parked outdoors, the waterproof film can be covered on the cushion to play a rainproof role, so that the riding discomfort caused by soaking the cushion by rainwater is avoided, and the influenc