The invention encompasses a removable attachment for installing on a bicycle with the goal of altering the resistance to either front tire or back tire revolution. In this way, the bicycle includes enhanced physical training capabilities allowing the rider to use a bicycle on a standard trainer frame or as a regular bicycle for riding in the usual manner. In one embodiment, the attachment includes a resistance support connected to a bicycle and supporting a resistance device that engages a bicycle wheel or bicycle tire for altering the resistance to tire revolution. In this exemplary embodiment, the apparatus includes a resistance support attached to the bicycle proximate a bicycle tire along with a resistance device removably attached to the resistance support. In one embodiment, the resistance device defines a slot, and the resistance support projects through the slot to position the resistance device against the bicycle wheel or the bicycle tire.