Abstract: A flexible coupling for connecting a driving shaft and a driven shaft together in an end-to-end relationship for transmitting power from the driving shaft to the driven shaft. Flexible coupling sub-assemblies which are balanced and aligned are provided between a center spacer member and coupling hubs attached to the driving shaft and to the driven shaft. The flexible coupling sub-assemblies each include a pair of annular adaptor rings having therebetween a flexible element member which preferably includes a plurality of side-by-side flexible members. The adaptor rings include an annular flange having on one side thereof a substantially radially extending countersunk face and on the other side thereof a substantially radially extending, generally planar face. The countersunk guide face guides the adaptor rings onto annular flanges of the coupling hubs and center spacer member to ensure proper alignment and balancing of the flexible coupling upon provision thereof with flexible elements.