Abstract: A high-spped anti-friction bearing particularly useful for airplane power plants, the bearing having an outer ring and an inner ring. The inner ring is axially split at the rolling elements into two axial sections. The axial sections are each generally L-shaped in cross section, with one arm of each L backed against the other. To enable the bearing rings to be relatively thin walled in the radial direction and to prevent undesirable deformation thereof during the manufacture or installation, each of the rings is provided on at least one axial side and preferably on both axial sides with projecting axial extensions. Each extension preferably tapers narrower in its radial thickness axially outward. Each extension includes a cylindrical portion and a frustoconically shaped portion, usually with the cylindrical portion axially more inward and the frustoconical portion axially more outward.