A modular cap assembly for covering a center bore of a wheel includes an outer piece having a first outward face with a cap retention structure formed therein, a first inward face, and a plurality of first mounting clips projecting from the first inward face to removably engage a wheel retention structure and couple the outer piece to the wheel. The cap assembly also includes a center piece having a second outward face, a second inward face, and a plurality of second mounting clips projecting from the second inward face to removably engage, one at a time, both the cap retention structure and the wheel retention structure. The second outward face is spaced from a wheel face when the center piece and outer piece are together coupled to the wheel and substantially flush with the wheel face when the center piece is coupled directly to the wheel.