I think max towing capacity is an issue that concerns more than just if the tractor can move the load or not. What about safety? Consider a 12,000 lb or larger trailer. Almost anything can still roll it around on level pavement, but what happens on an off-road trail with grades, tilts, and some bumps? Maybe the front wheels of the tractor bounce occasionally off the ground and you lose steering stability. Maybe the weight and inertia of the trailer pushes you down a hill and the brakes can't stop as fast as you want. Maybe during a turn, the trailer pushes or pulls on the tractor in such a way that it wants to roll over?
- Rick