I have an odd situation that I noticed my last couple of trips. I am getting a little sway only when I go on the interstate at 60mph. It's weird I can drive 60-65 on a regular 2 lane highway with no problem. I can drive 55 on the interstate no problem. The only difference from prior trips is one of the two propane tanks is empty I added a bigger battery in front, and I have a 100watt solar panel that's stored on the couch just back of the trailer tires. I know even the smallest weight change can make a difference but I'm questioning if the sway is because of the tongue weight or something else judging by the intermittentness. Camper tires are only one season old. Now the Tow vehicle tires are in bad need of replacing. Everything else is the same. I do use a sway bar when I tow and sway stops almost the second I let off the gas. It's not a bad sway, but it is felt. I have failed to check the pressure of the tires but visually they look the same. I have a front trunk on my camper that is always very full. Sadly I do not know the true weight of my setup . I know I should so I have a better idea.