A scuffing load capacity test with the FZG gear test rig for gear lubricants with high EP performance

Methods for the evaluation of the scuffing load capacity of EP lubricants of API GL-4 and GL-5 performance levels have been developed for the standard FZG gear test rig, which has a centre distance of a = 91.5 mm. Procedure A10/16.6R/90 is capable of discriminating between industrial gear oils and automotive gear oils up to GL-4 performance level while procedure S-A10/16.6R/90 can be applied to GL-4 and GL-5 lubricants. The test methods were verified with reference oils and commercial gear lubricants. The results of the tests can be used to give a relative ranking of reference and candidate lubricants. They can also be used as limiting values in the scuffing load capacity rating method according to DIN 3990 (ISO DIS 6336).