Abstract: An exerciser bike includes a frame having a front wheel and a handle for steering the front wheel, and includes two rear wheel axles. Two rear wheels are rotatably secured to the rear wheel axles by two ratchet sprocket wheels. Two foot supports each has a middle portion pivotally coupled to the frame. Two chains are engaged on the ratchet sprocket wheels and each has one end secured to the frame and the other end secured to the foot support, for allowing the rear wheels and the ratchet sprocket wheels to be driven by the foot supports via the chains. The exerciser bike may be turned with the rear wheels when the rear wheels are actuated with different speeds.