Load Ratings

Basic Static Load Rating

The basic static radial load rating (Cor) applies to bearings which rotate at very slow speeds, subjected to very slow oscillations, or stationary under load. It should be considered when heavy shock loading occurs to a rotating bearing. The basic static radial load rating is defined as the static radial load which corresponds to a calculated contact stress at the center of the most heavily loaded ball/raceway contact of 609000 PSI for all radial and angular contact ball bearings. For this contact stress, a total permanent deformation of rolling element and raceway occurs which is approximately 0.0001 of the rolling element diameter. Basic Static Load Rating for stainless steel is 75 80% of that for standard bearing steel.

Basic Dynamic Load Rating

The basic dynamic load rating (Cr) of a bearing with rotating inner ring and stationary outer ring is that load of constant direction and magnitude which a sufficiently large sample group of apparently identical bearings can endure for a basic rating life of one million revolutions.  

Values given for (C) in the bearing size charts are for standard chrome steel. 80% to 85% of the chrome steel values should be used for stainless steel.

Equivalent Dynamic Load Rating “P”

Typically load conditions on radial ball bearings are a combination of radial and axial loads. In order to establish the equivalent radial load with definite force and direction we use the following formula:

Cor/Fa e Fa/Fr≤e X Fa/Fr≤e Y Fa/Fr>e X Fa/Fr>e Y
5 0.35 1 0 0.56 1.26
10 0.29 1 0 0.56 1.49
15 0.27 1 0 0.56 1.64
20 0.25 1 0 0.56 1.76
25 0.24 1 0 0.56 1.85
30 0.23 1 0 0.56 1.92
50 0.20 1 0 0.56 2.13
70 0.19 1 0 0.56 2.28
P=XFr YFa(kgf)