Have a 2018 F-150, 2014 Coleman CT274BH, and a Blue Ox Sway Pro.
I have 13.5% tongue weight, transferring 400 to the front axle, and 200 to the trailer, removing 580 off the rear axle.
I have 1500 pound spring bars.
The problem I am having is that a car, SUV, or pickup will move me, and a light breeze will move me, but a passing semi moves the entire rig the way it is supposed to. I have it dialed in the best I can, at 60 MPH or below, no issues, can tow all day and not feel a thing. Get above 65 MPH and it can wiggle and squirm at random.
Is this due to the bars being too strong? My Sherline scale is a 5000 pound one, and measures just under 900 pounds of tongue weight, but the weigh ticket shows more like 1100 pounds weight. When distributed it is 910 pounds of weight on the ball.
Trailer is dead level too, setup by the book. I have tried adding and subtracting a link to no avail only made it worse. From the bar, 7 links is too much and sways are bad over 65, 9 links from the bar and it sways at 50 MPH. 8 links and it is the most stable, but still has more sway than it ever did with my 2014 F150 using a simple Husky round bar with a single sway control brake on it. I towed this trailer with that truck up and over the IKE into Utah and back to Illinois without a single sway issue. Had to replace the truck when it got totaled out on an icy road, with a 2016. I thought the issues with handling was with the 2016 truck itself, and the Husky, because it would wander all over the place, but not sway like it is doing now, just wander.
Now with the 2018 I have, which pulls it great, it will be nice and straight for miles and miles and then wiggle.
An SUV goes by, and wiggle.
Then today, I played with different lengths, and now have it with one link at 7, and one link at 8, and wiggle. I cannot seem to get this dialed in at all, yet my distribution is spot on.
So, thoughts? Too heavy a spring bar? Since the tongue weight is so close to 1000, and anything added to behind the rear axle should also be included, along with the weight of the hitch itself, it was over 1000 pounds, so went with the 1500 pound one.
I just hope it is something as simple as this and not an issue with the trailers axles causing it.