Self-aligning ball bearings have a spherical outer ring raceway, the center of whose curvature meets that of the bearing itself, so that the inner ring, balls and cage continue to rotate, aligning themselves if they have become misaligned within design limits. Koyo Self-Aligning Ball Bearing, Caged Light Tapered Bore, Series: 12 Series, 35 mm Bore, 72 mm OD, 2 Rows, 17 mm Width, Open Closure, 15.8 kN Dynamic/5.15 kN Static Load, Pressed Steel Cage, 8500 RPM Grease/10000 RPM Oil Maximum