Timken OK Load is a standardized measurement that indicates the possible performance of extreme pressure (EP) additives in a lubricating grease or oil. The units of measurement are pounds-force or kilograms-force. This measurement is performed using a special test machine and standard block and ring test specimens. The test machine is based on a machine manufactured by the Timken Company from 1935 to 1972, It is now an industry recognized standard test to compare extreme pressure resistance of greases and oils in a reproducible way.