I think this will be a better response. Runout is a term use to indicate how much variation exists when you turn a shaft or rotor 360 degrees. Runout is measure by using a dial indicator and setting the dial to .000. As the rotor is rotated the dial indicator will indicate the difference between the starting point and the point being measured. the value can be postive or negative. Different measurements for example .997(-.003) and .003 would indicate total run out of .006 inches. The higher the number the more noticaeable the warpage on the rotor. I would be concerned if the total runout exceeded .004 inches. Be sure to check the thickness of the rotors to make sure there is enough material to true the rotors if the runout exceeds specifications.