This Recommended Practice defines classes of tractors 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 various classifications for agricultural wheeled tractors. The classification is intended to aid in the selection of a seat for a specific tractor model and to reduce the amount of testing necessary to determine compliance with applicable standards and/or recommendations. Classification is based on basic configuration and total mass. Instrumentation and measurement procedures are specified in SAE J1013 JAN80. Test procedures are defined in SAE J1384. This document is in compliance with DIS 5007 adopted by ISO/TC23/SC3 October 1984 in Madrid, Spain.