Back-to-back arrangement

The back-to-back (O) arrangement pairs two angular contact ball bearings or tapered roller bearings so that their pressure lines diverge outward, forming an "O" shape. The pressure centers lie far apart, creating a wide effective support base.

Its key advantage is high tilting rigidity: it handles moment loads and overhung forces well, making it the standard choice for pinion shafts, wheel bearings and spindles requiring stiffness. Axial loads are supported in both directions, one bearing per direction. Thermal expansion affects the mutual adjustment and must be considered; preload or clearance is set during mounting, or factory-set in matched bearing sets (e.g. suffix DB).