Bearing Failure RCA: Wear


When a rolling bearing is damaged during machine operation, the entire machine or equipment can seize or malfunction. Since bearings that fail prematurely or unexpectedly cause trouble, it is important to be able to identify and predict failure beforehand, so that preventive measures can be adopted.

Damage Condition

Wear is surface deterioration due to sliding friction at the surface of the raceway, rolling elements, roller end faces, rib face, cage pockets, etc.

Possible Causes

  • Entry of debris
  • Progression from rust and electrical corrosion
  • Poor lubrication
  • Sliding due to irregular motion of rolling elements


  • Improve the sealing mechanism
  • Clean the housing
  • Filter the lubrication oil thoroughly
  • Check the lubricant and lubrication method
  • Prevent misalignment


Wear 1

Part: Inner ring of a cylindrical roller bearing
Symptom: Many pits occur due to electrical corrosion and wave-shaped Wear on raceway surface
Cause: Electrical corrosion


Wear 2

Part: Outer ring of a spherical roller bearing
Symptom: Wear with a wavy or concave-convex texture on loaded side of raceway surface
Cause: Entry of debris under repeated vibration while stationary


Wear 3

Part: Inner ring of a double-row tapered roller bearing
Symptom: Fretting Wear of raceway and stepped Wear on the rib face
Cause: Fretting progression due to excessive load while stationary


Wear 4

Part: Tapered rollers of damage “Wear 3”
Symptom: Stepped Wear on the roller head end faces
Cause: Fretting progression due to excessive load while stationary


Source: NSK