The ASTEC Tire Evaluation Center assures tire quality by measuring, grading, marking and sorting tires according to force variation, runout and sidewall appearance.

Force Variation is a tire behaviour that creates ride distrurbances such as vehicle vibration. Radial force variation induces forces into the vehicle on every tire rotation. Lateral forces can cause vibration and steering pull.

Runout is a measure of the "out-of-roundness" of a tire. Radial and lateral runouts also cause ride disturbances during every tire rotation.

Sidewall appearance reffers to the visual characteristics of a tire, and is influenced by tire construction features such as sidewall and body-ply splice accurancy and component quality. If splices overlap or are not put together properly, a depression or bulge in the sidewall appears when the tire is inflated.