Division 6.6.8 F1
The thickness of original material after buffing and the average thickness of any new material under the tread pattern after retreading shall be as given in paragraphs 6.6.8.1 and 6.6.8.2. The thickness of material at any point either across the breadth of the tread or around the circumference of the tyre shall be controlled in such a way that the provisions of paragraphs 6.7.5 and 6.7.6 are met.