JDeere7296

I have a hard time believing it's all just the tires. I've looked at the orginal photo where trailer was hooked up to truck. My FIL has an almost exact pontoon boat. The wheels on OP's trailer ARE further back, and are further back then similiar I've found online.

OP, I would maybe trade rims, tires but keep lift. Go to maybe 285/65 R18's. I also had a pair of air bags on my rear leaf springs that I would air up adjust the level when trailer was on. Of course that truck was a 2007 5.4 but I just don't see the tires being the main culprit here. I thinks it's mostly the trailer not being configured right.

sholland96

Maybe this has already been mentioned, but did you try disabling trailer sway control?

TexasFX4Aggie

Yup, no difference