Tire maintenance - Tire repairing Before having a tire repaired, tell the dealer if you have used an aerosol fixer to inflate/seal the tire. Aerosol fixers could contain a highly volatile gas. Always remove the valve core outdoors, away from sources of excessive heat, flame, or sparks and completely deflate the tire before removing it from the rim for repair. Never repair a tire with less than 2/32nd inch (1.6 millimeters) tread remaining. At this tread depth, the tire is worn out and must be replaced. Never repair a tire with a puncture larger than 1/4 inch (6.4 millimeters) in diameter. Such tires cannot be properly repaired and must be replaced. Repairs of all tires (radial and non-radial) must be of the plug and inside patch type. Using plugs alone on any type of tire is not a safe repair. Never repair a tire with a puncture or other damage outside the tread area (shoulder, sidewall) Such tires cannot be properly repaired and must be replaced. Any tire repair done without removing the tire from the rim is improper. Tubes, like tires, should be repaired only by a qualified tire service person. Never use a tube as a substitute for a proper repair.