Originally Posted by crashnzuk
I'd look to see if any of the tires are flat spotted from brake lock-up. My right side forward tire on my trailer had a few flat spots on it because that brake was too tight when I bought it. It's hard to notice a tire locking up on an empty trailer, It didn't take long to ruin that tire. Non-round tires will transmit to the truck pretty badly.
Ding ding ding! We have a winner. I went to get them rebalanced today and on the way there I topped a hill on a 2 lane blacktop to find a car stopped in the lane waiting to turn. I mashed the brakes and trailer tires locked and smoked. Pretty sure that is the issue. Previous owner had the brake controller set for loaded weight and when running empty the tires were locking up and sliding. I watched them rebalance them and could see the tires running out of round. i asked the kid if the rims were running true and he said they are. They looked to be true to me too. Got them rebalanced and it's a little better but still shakes between 65-70mph. The sweet spot for highway speed. Gonna call a local retread place on Monday to see if they can shave them to true them up. The tires are damn near new and marked regroovable on the sidewall. I know the shaving used to be a thing with heavy trucks in the past but not sure if it is anymore??