CAT 545-8255 75mm Outer Diameter Wheel Bearing

CAT 545-8255 is a Caterpillar double-row tapered roller bearing, suitable for drive axle/steering wheel axles of equipment such as loaders and graders. It is designed to withstand radial and bidirectional axial combined loads under heavy-duty conditions, and features high load capacity, impact resistance and long service life. It is a key component to ensure stable wheel operation and transmit driving force and braking torque, and is suitable for low-speed heavy-duty, frequent start-stop and steering conditions. The following is structured technical and application information:

Core Technical Parameters

Item Details
Basic Attributes
Model 545-8255, Type: Double-row tapered roller bearing (including inner ring, outer ring, rollers, and cage), Material: Carburized bearing steel (chromium-molybdenum alloy, quenching hardness HRC 60-64), Cage: One-piece stamped steel plate, Single weight: Approximately 7.8 kg, Operating temperature: -30℃ to +120℃, Lubrication method: Grease lubrication (Recommended: Cat 5P-0960 extreme pressure lithium-based grease), Design life: ≥10000 hours (normal operating conditions)

Key Dimensions
Inner diameter: 127 mm (5 inches, tolerance 0/+0.018 mm), Outer diameter: 241.3 mm (9.5 inches, tolerance 0/-0.022 mm), Total width: 82.55 mm (3.25 inches, tolerance 0/-0.15 mm), Number of rollers: 24 (Double row, evenly distributed, 18 mm diameter), radial clearance C4 grade (0.04-0.06 mm), mounting chamfer r2=2 mm, recommended preload torque 120-150 N·m
Compatible Models and Parts: Compatible with Cat 966M, 972M loaders (front drive axle), 140M graders (steering wheel axle), M320F wheeled excavators (drive wheel axle), with matching 203-0711 retainer, 103-8329 elastic retaining ring, 5P-0960 grease, 4T-0512 oil seal
Performance Parameters: Basic rated dynamic load 420 kN, basic rated static load 680 kN, limiting speed (grease lubrication) 1800 r/min, allowable axial load ≥250 kN, coefficient of friction ≤0.002, impact load ≥80 kN, recommended lubrication interval 1000 500 hours (Heavy load/Harsh conditions)

Structural and Performance Advantages:
Double-row tapered roller bearing structure, capable of simultaneously withstanding large radial loads and bidirectional axial loads, suitable for the combined forces during wheel steering and driving. Carburized bearing steel enhances surface hardness and core toughness, providing strong fatigue and impact resistance, suitable for heavy loads and bumpy road conditions.

Integral stamped steel cage ensures even roller distribution, smooth operation, and reduced vibration and noise. The double-row design further evens load distribution, reduces individual roller stress, and extends bearing life. The separate inner ring facilitates installation and preload adjustment.

Taply rolled roller line contact design minimizes contact stress and increases load-bearing efficiency, suitable for transmitting high torque and braking loads in drive axles, preventing wheel axle movement and ensuring driving stability and braking reliability.

Installation and Maintenance Points: Before installation, clean the bearing inner and outer rings, journal, and hub housing. Check for rust, burrs, or dents. Measure the journal diameter (127 mm) and bearing inner diameter, and the hub housing and bearing outer diameter, ensuring an interference fit of 0.01-0.03 mm. Pre-tighten the bearing according to specifications (120-150 N·m) to avoid over-tightening leading to overheating or under-tightening causing movement.

After installation, check the bearing’s rotational flexibility for any jamming or abnormal noise. Install the oil seal and hub, and add sufficient grease (filling 1/2-2/3 of the bearing cavity), ensuring the grease fills the roller clearance. Tighten the hub bolts to the specified torque (according to the model manual).

Maintenance: Check the bearing temperature, clearance and lubrication status every 1000 hours. If the temperature rises abnormally (>80℃), the clearance exceeds 0.1 mm or the grease deteriorates, repair immediately. When replacing, two bearings of the same axle must be replaced in pairs. Do not mix bearings of different models or brands to avoid uneven stress on the wheel axle.