PURPOSE: To enhance the reliability of detecting damage to cords in the carcass of a tire and to reduce costs by comparing a baseline measurement taken when the tire is inflated to minimum pressure with raised pressure measurement.

CONSTITUTION: A computer 26 collects data from a deviation sensor 20 and analyzes it. When a tire 30 is laced on a stem 22, air is pressed into the tire 30 through a hose 24 until at least a sufficient value to keep the tire 30 from moving on the shaft 22 is reached. Minimum air pressure for baseline measurement is 0.035 to 0.703kg/cm2. The pressure is selected using a control board 12, and a regulating valve 28 maintains the pressure at the selected value. For a raised pressure measurement, the tire 30 is inflated to 0.387 to 2.812kg/cm2 and rotated, and data originated at a sensor 20 is collected. After taking the baseline and raised pressure measurements, both of the measurements are compared. If there is a damaged carcass cord, the difference between peaks corresponding to the damaged cord is markedly exaggerated during the raised pressure measurement.