85_Ranger4x4 said:
Trim usually doesn’t dictate towing capacity.
things like roll stability control, spring rates, brakes, and engine/transmission cooling play a big roll in the towing capacities.
At a certain level, trim does dictate towing capacity:
The 13,200lb max towing for the F-150 requires the lightest possible truck - regular cab/long box, but that combination is only available in a XLT or lower trim. It can't be the heavy duty payload package, as the heavier frame/axle/springs of the HDPP adds too much weight, but rather a very specific option combination (Manual windows, mirrors, center mini console w/column shifter, etc - to get weight out of truck. Note: It is 3.55 gears, not the lower 3.73s for the max tow package.
SuperCabs lose 100lbs/SuperCrew 200lbs in F-150s; 4WD costs an additional 200lbs.
You missed tires in the towing equation - the 22" tires of the F-150 Limited kill towing capacity.
Now, much of the above doesn't apply to Rangers, as they all have same engine/transmission, brakes, tires, etc. But, as originally noted by 2002edgeplussupercab, the max towing with probably be a 2wd, SuperCab XL - the lightest Ranger. A SuperCrew 4WD Lariat will probably be rated <7klbs.
85_Ranger4x4 said:
The FX4's have a thing like the Subaru that uses the brakes to get power to where it is needed.
My FX4 F-150 has the electrical locker in differential, not a brakes thing.
The <5mph limit really wasn't issue on the steep/slimy boat ramp