On tracked chassis operating machinery, most drive wheels are arranged at the rear. The advantage of this arrangement is that it can shorten the length of the track drive section, reduce the friction loss at the track pin caused by driving force, extend the service life of the track, and prevent the lower part of the track from arching, avoiding the danger of track detachment during steering and improving the efficiency of the walking system. The height of the driving wheel should be conducive to reducing (or increasing) the height of the vehicle body and increasing the length of the track contact and adhesion performance, so the height of the driving wheel should be as small as possible.

The function of the pulley is to hold the track, prevent the track from sagging too much, reduce the vibration and jumping phenomenon of the track during movement, and prevent the track from sliding laterally. The supporting pulley is similar to the supporting pulley, but it bears a smaller load and has better working conditions than the supporting pulley, so its size is smaller.