Pump Bearing Selection: Matching Bearings to Pump Types

Pumps are one of the most common bearing applications in industrial facilities. The right bearing selection depends on pump type, speed, load, and the fluid being pumped.

Centrifugal Pumps

The most common pump type in HVAC, water treatment, and process industries. - Radial bearing (inboard): Deep groove ball bearing — handles radial loads from impeller weight and hydraulic forces. Common sizes: 6205 through 6316 - Thrust bearing (outboard): Angular contact ball bearing or paired deep groove — handles axial thrust from hydraulic pressure. Pumps generate significant axial force that increases with system pressure - Mounting: Typical shaft tolerance k5 or m5, housing H7 - Lubrication: Oil bath for high-speed pumps, grease for standard-speed. ISO VG 68 oil for most process pumps

Positive Displacement Pumps (Gear, Vane, Piston) - Higher radial loads than centrifugal due to pressure pulsation - Cylindrical roller bearings for radial loads in heavy-duty gear pumps - Tapered roller bearings where combined radial and thrust loads exist - Sealed bearings if oil mist contamination is a concern

Submersible & Vertical Pumps - Thrust bearings handle the weight of the pump shaft, impeller, and water column - Angular contact ball bearings in back-to-back (DB) arrangement common for combined loads - Water-lubricated sleeve bearings used for line shaft bearings in vertical turbine pumps - Corrosion-resistant materials (stainless, ceramic) for water and chemical service

Key Failure Modes in Pump Bearings - Thrust overload from operating away from Best Efficiency Point (BEP) - Contamination from seal leaks — water in grease destroys bearings fast - Electrical discharge damage in VFD-driven pump motors - Misalignment between motor and pump shafts

Service Bearing stocks the most common pump bearing sizes and can cross-reference any OEM pump bearing. Contact us with your pump model and we'll identify the correct bearings.