This recommended practice pertains to operator seats for the earthmoving category of off-road self-propelled work machines as defined in SAE J1116 JUN81. This recommended practice defines classes of earthmoving machines having similar characteristics which affect the vibration transmitted to the operator through the operator seat. This recommended practice establishes input data parameters for conducting operator seat vibration tests for the various classes. The purpose is to aid in the selection of an operator seat for a specific machine model and to reduce the amount of testing necessary to determine compliance with applicable standards and/or recommendations. Test procedures are specified in SAE J1384. Instrumentation and measurement procedures are specified in SAE J1013 JAN80.