This is not a safety recall in accordance with the Safety Act. However, it is deemed a safety improvement campaign by the Agency. Equipment description: Ford is replacing all Firestone Wilderness AT 15, 16, and 17 inch tires mounted on Ford trucks and SUVS. Ford reports tread separation can occur due to a combination of the sensitivity of the tire design to stress, aging, and manufacturing differences between plants. Ford is replacing these tires to prevent possible premature tire failure. Vehicle description: The vehicles listed below may have been originally equipped with Firestone Wilderness AT tires or may have had Wilderness AT tires installed during the Firestone recall launched in August 2000. Certain 1991 throught 2002 Ford Explorer certain 2001 throught 2002 Explorer Sport, and Sport Trac certain 1997 through 2002 Mercury Mountaineer certain 1991 through 2001 Ranger certain 1999 through 2001 Expedition certain 1991 through 1994, and 1997 model year F-series certain 1991 through 1994 Bronco note: Both original equipment and replacement tires are affected.