Single-row contact ball bearings can only carry pure axial loads in one direction, and the capacity increases with contact angle . The nominal contact angles are 15°, 25°and 40°. When the bearings carry radial loads , the inner and outer rings will be separated because of additional axial force . They are normally mounted in pairs . Metal solid cages are mainly used in single-row contact ball bearings. Phenolic cloth laminated tube solid cages are usually used for high speed applications , and the maximum temperature is 120℃ .