From experiance on trailer's - usually a bent rim is the culprit from a really bad out of balance issue -
check to see if you have any wheel weights on the inside - or the other thing is they could be using the sand bags inside the tire which is what they have been using on Motor Homes and Semi Tractor Trailer's - the bag goes around the inside of the tire as you drive around and balances the tire at the same time.
2011 Rockwood Mini Lite 2306 - Matt
2004 Dodge Ram 1500 Qaud Cab 4x4 with 35" tires and 3.92 gears, Dynatech Longtube Headers & Fabtech 6" lift + Superchips with shift Tuning
Nights Camped 2011 (37) - 2012 (16)-2013 (2) -2014 (5) -2015(0)
USMC 91 - 95 - F/A-18 Aviation Ordnance