Bumper Pull Trailer Vibration

Rythmic vibration at 70 mph

It can best be described as if I merged into the rumble strips, and back off, back on, and back off. It would pulsate from nothing, to very noticible

https://www.ramforumz.com/threads/help-pulsating-vibration-when-towing-a-trailer.112144/

https://www.irv2.com/forums/f45/harmonic-bounce-what-to-do-505601.html

TODO

[X] Balance trailer tires

[X] Add 500 lbs of weight to trailer over axles

[ ] Test trailer with different truck

[ ] Rotate and balance truck tires