Rewind is right on track. Radial tires are somewhat prone to two defects. A mostly invisible condition called radial tire pull happens when slight ply separations occur. The natural propensity for the tire to roll straight is affected by off-design ply angles. Tires that are layed up on a mandrel and heat pressed and vulcanized suffer this more than the segmented mold style. The other condition is a more severe ply separation where a slight bulge may occur. This causes irregular tire wear, such as cupping, felt vibration, and sometimes blowout. I would also check to ensure that the axle/tires are aligned to the medial plane or natural centerline of the trailer, and that no out of spec toe or camber conditions exist. It has been suggested that tire wear while towing on curvy roads such as mountain roads is better accomplished with a slight positive camber to offset the load bias on the tire as weight is transferred side to side. This is true only on radial tires however. When you shop for tires, look for high ply ratings on both the tread and sidewall for increased handling feel. Hope we've helped you a little! Good luck.