So....even if you weigh 60,000 lbs, give or take a few thousand, you can still adjust it from the comfort of the seat. You don't even have to get off. Beautiful.
It'd be easy to do with the hydro drive unit from a lawn tractor hooked up to the splitter pump with a lever for forward/reverse. With those size tires it'd be fast enough to get you into trouble too.
Also looks like he took about 6" of the ATC frame so he didn't have to fabricate a pivot for the steering. The front rack is still there as well, must have been a Big Red.