本文件规定了用于农业拖拉机和机器的新轮胎在负载条件下滚动周长的测量方法，适用于对角线和径向结构的农业拖拉机驱动轮轮胎。它还包括对滚动周长指数（RCI）和速度半径指数（SRI）的解释。

This document specifies the method for measuring rolling circumference for new tyres, under loaded conditions, made for use on agricultural tractors and machines, and applies to agricultural tractor drive wheel tyres in diagonal and radial construction. It also includes an explanation of the rolling circumference index (RCI) and speed radius index (SRI).