Not having ever seen a definition of either rivering or cupping, I'm assuming the "rivering" is a wavy wear pattern across the traed and around it and that "cupping" is a deeper wear pattern across the width and at regular intervals around the circumference.
Based on engineering priciples and these assumptions, I would expect "rivering" to be caused by either a bent wheel rim or a loose wheel bearing which allows the wheel to wander in the yaw axis.
I would expect "cupping" to be either a function of wheel imbalance or a dented wheel that allows fluctuation in the vertical axis of the wheel.
Am I making incrorrect assumptions?
