The invention relates to a bicycle twist-grip shifter, which is connectable to a fixed handgrip and is mountable as a structural unit on a handlebar. In this way the fixed handgrip is securely fixed on the handlebar. Moreover, the individual components have an advantageous size for production in an injection molding process. The twist-grip shifter gives the operator a precise operation by avoiding disruptive frictional effects of the rotatable handgrip part on the mounting tube, for which purpose ball bearings are used for bearing the take-up spool, and a metallic positioning ring is used in the positioning mechanism.