Sprocket or gear with metal hub

A rotary polymeric torque transfer device adapted to be mounted on rotatable shaft structure comprising, a polymeric body having an axis of rotation, a circular periphery, first and second sides, a central opening defined in said polymeric body extending through said sides coaxial with said axis of rotation, a shoulder defined adjacent said body first side radially spaced from said axis of rotation and torque transfer elements defined on said periphery, a drive member disposed adjacent said body first side having a central portion, an inner portion and an outer portion, a hub defined on said drive member inner portion coaxially extending into said polymeric body opening to concentrically engaged with the rotational shaft structure, fastener receiving means defined on said drive member central portion for receiving a fastener to maintain said drive member in frictional engagement with said body first side, and a torque drive element defined on said drive member outer portion engaging said body shoulder to therefore transfer torque between said drive member and said polymeric body.