The purpose of the test is to measure the ability of a grease to lubricate at various high speeds, temperatures and axial loads. The grease quality is measured by recording the number of running hours before the grease ceases to lubricate and, as a onsequence, the bearings fail. The longer the number of running hours in the test unit, the more effectively the grease lubricates under those conditions. In this way the maximum operating speed, temperature and load for a particular grease can be determined.