I don't know unless the axles and suspension are flexing more but I can't see the tires doing. My trailer has 6k axles and I am usually pretty consistent at 11600/11800 which puts me on the upper limit as well as the tires at 3042 lbs per tire. What I can tell you is the 1st trip with this pig was bringing it home on the stock GY Marathons it towed like a drunken rock. I was talking to the tire guy I dealt with for years on my class 8 trucks and suggested the R250 as I used to run a similar tire on the steering and trailers. Now I can tell you the trailer tows better behind my dually better than it ever did behind the pickup. It may be the air pressure you have them set at but it sounds like you are a lot lighter than a lot of us. Truck 10,600 + trailer 14,200 + 4700 boat behind and we are getting right up there but tows good and straight which you can see by watching the 2nd trailer. My suggestion would be adjust tire pressures to see if it makes a difference.