[sparkycuda]

The "front" vs "rear" of the undercarriage is determined by the operator controls. All manufacturers I'm familiar with designate the idler end as "front" and the track controls work correctly in that direction. If the upper works are rotated 180 degress (operator being over the sprockets) the track controls are backwards. Additionally, there are other reasons the idler is the "front". The track recoil spring is mounted behind the idler to absorb shock loads as the machine moves and hits rocks, etc. Sprockets pull the tracks directly when going forward, as opposed to reverse, when the track is under tension on top, around the idler, and on the bottom - increasing track wear significantly. Excavators typically don't travel very fast or far, so going either direction is not as detrimental as on a dozer. Besides, if you are straddling a ditch, you don't have much choice about which end leads! Hope that helps.

Ken