2009 Dodge Ram 3500 Pickup Owner Manual - Page 349

STARTING AND OPERATING 347 Tires designed to this standard have the letter "T" molded into the sidewall preceding the size designation. Example: T145/80D18 103M. Tire Sizing Chart Size Designation: • High flotation tire sizing is based on U.S. design standards and it begins with the tire diameter molded into the sidewall. Example: 31x10.5 R15 LT. EXAMPLE: P = Passenger car tire size based on U.S. design standards ؆...blank...؆ = Passenger car tire based on European design standards LT = Light truck tire based on U.S. design standards T = Temporary spare tire 31 = Overall diameter in inches (in) 215 = Section width in millimeters (mm) 65 = Aspect ratio in percent (%) - Ratio of section height to section width of tire 10.5 = Section width in inches (in) R = Construction code - ЉRЉ means radial construction -ЉDЉ means diagonal or bias construction 15 = Rim diameter in inches (in) 5