Yes - something at the rear sprocket is not right ---- if you copy that picture to your computer and increase the size - zooming into the rear, you can see one link of the rail and
the dia of that sprocket showing certainly does not look correct either. Rear Carrier Roller is way too high also.

Just a thought - so you suppose they could have done something to effect a gear reduction back there to slow the machine down even more than Low would provide -yet deliver the power needed to pull the load in that soil?

Yes - something at the rear sprocket is not right ---- if you copy that picture to your computer and increase the size - zooming into the rear, you can see one link of the rail and
the dia of that sprocket showing certainly does not look correct either. Rear Carrier Roller is way too high also.

Just a thought - so you suppose they could have done something to effect a gear reduction back there to slow the machine down even more than Low would provide -yet deliver the power needed to pull the load in that soil?

I attempted to enlarge to show the detail - 
CTS

Most likely speed reduction with the small sprocket.

Rome - that was my thoughts too -
Look in the area where the track would come over the top of the "original" drive sprocket - those pads do not look like they are following as in a "high track" which this would emulate?
Picture is not great for showing detail nor is there notation in the description.
Just some thoughts

I apologize for the duplicate post above, I would remove if I knew how!
CTS

Yea if they wanted the just more clearance, they would have just raised the tractor and sprockets and kept the same diameter sprockets.

Hi, Folks.
Here is another 'slightly modified purpose built' RD4 at work rose harvesting:



Just my 0.02.

Maybe so they didn't have to take any links out of the tracks?

Sexy! high heels! lol