Life" is the number of hours that a percentage of similar bearings have survived under an essentially identical set of operating conditions and loads.  Life can be affected by a number of factors including loads, speed, lubrication, fit, maintenance, temperature, contamination and others.

Bearing life is defined as the length of time (number of revolutions) until a specific failure occurs. Predicting the life of a ball bearing is a statistical calculation of the fatigue properties of the various bearing components. Fatigue Life (L10 or Rating Life) of bearings is the number of hours or revolutions reached by 90 percent of a group of bearings subjected to the same loads before the onset of fatigue. Conversely, 10 percent of the same group of bearings can be expected to show evidence of fatigue before the L10 Life is reached. 

Many variables can impact bearing life. Various factors such as handling and contamination damage can dramatically reduce bearing life. Bearings should be properly stored, mounted, dismounted, and inspected.  Optimized performance and life is also contingent on appropriate lubrication and sufficient protection from foreign matter.  Bearings should be stored in a cool, clean, low humidity environment free of dust, shocks and vibrations.  Proper fitting, using specialized tools and techniques, will also help maximize bearing life. 

Pacamor Kubar offers a Life Load Calculator for bearings subjected to radial loads or combined radial and axial loads. Please contact the company if the calculated life is borderline in comparison to the desired life or if the loading conditions differ from those presented. Additionally, Pacamor offers a bearing installation guide, bearing handling practices and a detailed chart for shanft and housing fits.