If a metric micrometer reads 16.22mm and the rotor discard thickness is 20.25mm, how much is the rotor below minimum thickness?

To determine how much the rotor is below the minimum thickness, you need to subtract the measurement of the micrometer from the discard thickness of the rotor.

The rotor discard thickness is 20.25mm, and the micrometer reading is 16.22mm. By performing the subtraction:

20.25mm (discard thickness) - 16.22mm (micrometer measurement) = 4.03mm.

This calculation indicates that the rotor is 4.03mm below the minimum thickness requirement. Therefore, the answer is correct because it accurately reflects the difference between the two measurements, providing a clear indication of how much the rotor fails to meet the necessary thickness.