If spherical plain bearings and rod ends are subjected to static loads, or very slight alignment movements, then the permissible load is not limited by wear, but by the strength of the sliding contact layer or the strength of the rod end housing.

If the actual load is a combined load, then an equivalent static bearing load must be calculated. For radial and angular contact spherical plain bearings, it can be calculated using

P0 = y Fr

For thrust spherical plain bearings, it can be calculated using

P0 = y Fa

where

 P0 = equivalent static bearing load [kN] Fr = radial component of the load [kN] Fa = axial component of the load [kN] y = load factor that depends on the ratio of the axial to the radial load Fr/Fa for spherical plain bearings requiring maintenance and SKF Explorer steel/steel bearings (diagram 1) for maintenance-free radial spherical plain bearings (diagram 2) for angular contact spherical plain bearings (diagram 3) and load factor that depends on the ratio of the radial to the axial load Fa/Fr for thrust spherical plain bearings (diagram 4) 