Goodyear has issued the following procedure to repair punctures in Z-rated tires and still retain their speed rating: CAREFULLY REMOVE THE TIRE COMPLETELY FROM THE RIM. Locate the puncture on the inside of the tire and circle with crayon. Remove puncturing object if it is still in the tire. Carefully inspect tire on a good tire spreader, with ample light, which will show any cracks, breaks, punctures, damaged or broken beads. Check liner for cuts, cracks, or holes which may cause the tubeless liner to lose air. Check the injury with an inspection awl: Determine size and angle of injury Check for ply or belt separation Reject any tire that has separation, loose cords, damaged bead(s), or any other non-repairable injury. If the hole is simple and round, steps 9 through 17 of the puncture repair procedure will be successful. NOTE: If the hole shows evidence of fabric splitting, such an injury cannot be properly repaired using this puncture repair procedure. Such an injury must be skived out and repaired as a section (reinforced) repair, which will maintain the serviceability of the tire, but will invalidate the tire's speed rating. If a section repair is necessary, the customer must be advised, before the repair is made, that the tire will lose its speed rating, and must not exceed operation at normal highway speeds. Use a pre-buff cleaner and a scraper to remove contaminants from the liner in the area to be buffed around the injury. Use a 7/32"carbide cutter for ¼" repairs to clean out the puncture. Make sure that the drill follows the direction of the puncturing object. Always drill from inside to outside of tire. Using chemical vulcanizing cement, lightly coat at least 1/2 of the tapered end of the repair plug. Install the plug in the prepared puncture according to the manufacturer's instructions. Trim the liner side of the plug slightly higher than the surface of the liner without stretching the plug. Center the patch (or patch template) over the injury without removing the backing. Adhere to patch or template instructions, as to positioning as related to bead location. Using a marking crayon, mark around the outside edge of the patch, approximately 1/4" larger than the patch. Buff the liner and plug at the puncture location. The buffed area should be slightly larger than the patch. The buffed surface should be finely grained (RMA 1 or 2 texture) and even for proper bonding. Use care to prevent burning the rubber with the buffing tool. Do not buff through the liner. Do not buff into the marking crayon. Clean the buffing dust from the tire using only a vacuum or brush. Do not use gasoline or other petroleum solvents on the buffed area. Coat the buffed liner surface and the patch with one evenly applied coat of chemical vulcanizing cement in accordance with the recommendations of the repair materials manufacturer. Allow the cement to dry thoroughly. Do not touch the cemented areas. Install the patch with the beads of the tire in the relaxed position. Position the patch over the puncture according to the markings on the patch. Stitch the entire patch starting from the center, keeping the strokes close together to avoid trapping air under the patch. Cut off the protruding end of the plug about 1/8" above the tread surface. FINAL INSPECTION - The repair must seal the inner liner and fill the injury. After remounting and inflating check the repair, both beads and valve with a soap solution to assure a complete seal.
