New to this site so hopefully so hopefully I am posting in the correct spot. I had an issue towing my boat and trailer this weekend. Quick background. Boat and trailer is a 2000 Bass Tracker Pro Team 175W. I bought this last year and have had it out a ton with no issues. Friday 3-18-16 we went to Mozingo Lake about 40 miles from home and had no issues on the way up. On the return trip home I stopped to drop my friend off (probably 30 miles into the return trip with no issues still). When I got back on the highway after a mile maybe I noticed something was wrong. My truck felt like it had the brakes on and when I let off the throttle there was a horrible shake/vibration in the truck and the truck slowed more than normal. This continued for several miles and eventually smoothed out some. I have not towed the boat since but I have checked a few things.
Bearings look and feel great. No slop in the wheels and sounds smooth when spun. They have not been replaced since I have owned the boat but I have greased them.
Tires do have a noticable flat spot (maybe 3-4 inches long) on the inside portion of the tire. The inside looks to be worn more than the outside. I assume the tires are the original ones.
Anything else I can check would be much appreciated. Could this be caused by the tires being in the condition I described?