Tyre wear may be caused by mis-alignment of the two wheels with each other. As trailer axels are called on to carry what may be termed excessive weight, there will be bending of the axle which tends to reduce the amount of camber built into the axle. Camber is that quality of design in the axle which causes the portions of the two tyres in contact with the roadway to be closer together than the top surface of the same tyres, being so designed to compensate for both weight and the crown of the road. If the trailer is overloaded and the camber reversed then the inside of the tyre will wear rapidly.
A tyre with a normal pressure of 30lbs. May have to go as high as 40 or 45lbs in order that the trailer tyres may stand up to without undue flattening. With under inflated tyres a weaving motion is set up. The tyres of the towing vehicle should stand up full and round with out any tendency to flatten.