Abstract: A pulley brace for mounting between a variable diameter driving pulley which is belt-coupled to a variable diameter driven pulley, the pulley brace consisting of an elongated body having first and second body ends and a central body portion therebetween, a first bearing connection on the first body end for coupling the elongated body to the driving pulley and a second bearing connection on the second body end for coupling the elongated body to the driven pulley and a turnbuckle arrangement at the central body portion for varying the distance between the first and second connections.