A rotary indexing apparatus for positioning an external component secured thereto at one of a plurality of incrementally arranged detent positions. The apparatus includes a race ring having a race surface facing inwardly toward a central axis of the ring. The surface has alternating hills and valleys, each valley corresponding to a detent position. A detent wheel on a selection shaft is rotatable within the ring via the shaft. Two spring loaded, opposed race wheels on axles movably mounted within the detent wheel roll along the race surface while the shaft is being rotated. The race wheels roll into valleys upon a halting of the rotation. The apparatus facilitates positive positioning of the selection shaft while reducing friction.