The Timken Company 34478 Tapered Roller Bearing Cup

The Timken 34478 is the outer ring (cup) of a single-row tapered roller bearing from the 34000 Series, engineered to carry combined radial and axial loads while maintaining precise shaft alignment when paired with compatible Timken cones. It is designed to be installed with cones 34300, 34300A, 34301, or 34304 to form a complete bearing assembly, and it features a precision-ground raceway and separable cup design for straightforward installation and maintenance. Key specifications include an outside diameter of 4.7812 in (121.442 mm), a cup width of 0.6875 in (17.463 mm), and through-hardened bearing steel construction with a weight of approximately 1.10 kg (2.4 lb); dynamic radial load rating (C1) 102,000 N (23,000 lbf), static radial load rating (C0) 136,000 N (30,600 lbf), and dynamic axial load rating (Ca90) 20,500 N (4,600 lbf). Common applications encompass industrial gearboxes, heavy-duty conveyors, mining equipment, construction machinery, and other heavy-duty rotating systems that demand high load capacity and long service life.