Newbie Question on 2016 F150 2.7L SuperCab 3.55 4x4

I take the 5,100 lbs to be the tow limit. The likely reason would be a smaller radiator, and smaller transmission cooler, or lack of one.

The 10% tongue weight is normally the minimum, it would be better to have 12-13%.

The 80% factor is a personal preference. Ford has outlined the limits, that I would follow. However, towing right at the limit of everything, may not be as good an experience as having a little cushion.

Jerry