Abstract: A process monitoring and control system is provided for use in a tire calendering system producing a strip of rubber tire material comprising a layer of tire cord laminated between first and second layers of rubber. In a preferred embodiment, the thickness of the first rubber layer is measured by a single point radiation backscatter gauge at a point prior to its lamination with the tire cord and second layer. The thickness of the first layer is controlled to a desired target by means of a control loop including the single point gauge. The total thickness of the combined layers is measured at the calender output by a total thickness gauge. Gauge coordination means, including a delay means, are provided whereby measurements of the thickness of the first layer and of the combined strip are derived over the same longitudinal portion of the strip.