The back axle on our travel trailer is bent back so that the back edge of the rear tire is 1.5" out of line with the front ones on both sides. The right rear is also 1.5" out of plumb.The left not as ...
Like OLD BISCUIT AND B O said pull the trailer in a straight line and then look at it. When turning it puts the axle in a bind but goes back when you drive straight.