Technical Bulletin (Vibrations in Steering Wheel):
After a short stationary period (sometimes as little as a few hours) flat spots can develop after the warm tire has cooled down. The effect the flat spotted tire has on the vehicles performance depends on the type, dimension, make, and pressure of the tire.
This document informs how to identifiy Flat spots that alter the radial force variation and must be driven out before balancing the wheel.
