CAT 521-9954 BEARING-SEM

CAT 521-9954 is a single-row tapered roller bearing customized by Caterpillar for SEM loaders. It is suitable for medium- and heavy-duty components such as drive axles and differentials. The following are precise original factory specifications and application information, excluding replacement parts Cat®…

Core Technical Parameters

Item Details
Part Model: CAT 521-9954 (SEM Custom Single Row Tapered Roller Bearing)

Bearing Type: Single row tapered roller bearing, including inner ring (cone) + outer ring (cup) + rollers + cage, suitable for pure radial and unidirectional axial combined loads Cat®…

Material: Inner ring / outer ring / rollers are made of high carbon chromium bearing steel (AISI 52100), hardness 60–64 HRC; cage is made of stamped steel plate, galvanized for corrosion protection.

Key Dimensions: Inner diameter 65 mm (2.559 in), outer diameter 120 mm (4.724 in), width 37 mm (1.457 in), cone angle 10°30′, chamfer radius r=2 mm

Rated Parameters: Radial dynamic load rating 92.5 kN, axial dynamic load rating 45.2 kN; radial static load rating 115 kN, axial static load rating… 68.8 kN; Limiting speed 4500 rpm (oil lubrication), 3200 rpm (grease lubrication); Operating temperature -30℃ ~ +120℃
Single weight approx. 1.42 kg (3.131 lbs)
Tolerances: Inner diameter tolerance P6, outer diameter tolerance P6, radial clearance C3, contact angle accuracy ±15′, surface roughness Ra ≤ 0.4 μm
Recommended lubrication: NLGI 2 extreme pressure lithium-based grease or ISO VG 68 anti-wear hydraulic oil, suitable for medium-low speed heavy loads and vibration conditions.
Structure and core characteristics:
Cut roller structure: The rollers and raceways have a tapered contact, capable of simultaneously withstanding large radial loads and unidirectional axial loads, suitable for drive axles, differentials, and other components subjected to complex stresses.

Modular design: Inner ring, outer ring, rollers, and cage are supplied as a single unit, facilitating easy installation and precise positioning, suitable for the compact space of SEM loader drive axles.

High-precision manufacturing: P6 tolerance and C3 clearance ensure stable operation at low and medium speeds, reduce vibration and noise, and meet the heavy-duty operation requirements of loaders.

Impact-resistant reinforcement: The stamped steel plate cage has strong impact resistance, suitable for harsh working conditions such as mining and infrastructure construction, and extends bearing life.

Compatible models and application scenarios:

Compatible equipment: CAT SEM 655D/656D/658D loaders, SEM 816D/822D bulldozers, and other SEM series construction machinery Cat®…

Core applications: Used in drive axle main reducers, differential housings, drive shaft supports, etc., to transmit heavy loads, absorb vibration, and ensure stable operation of components, suitable for medium and heavy-duty operations in mining, infrastructure construction, and other similar conditions.