A method and apparatus for buffing tread from a tire carcass, the method comprising the steps of: positioning a sensor at a first lateral location along a width of the tread; receiving a first signal from the sensor, the first signal generated as a function of a distance between the sensor and a belt in the tire and a tire characteristic; selecting a first signal response curve from a plurality of signal response curves based upon the first lateral location of the sensor, the selected signal response curve representing the function of the distance between the sensor and the tire belt and the tire characteristic; determining from the response curve the distance between the sensor and the belt for the signal response received; buffing tread from the tire until the distance between the sensor and the belt reaches a final distance. The steps are repeated at a second lateral location.