The 1991 Pontiac Sunbird tire size depends on trim: the Base, 2D Coupe, Automatic, 125C/MD9 takes P185/75R14; the Base, 4D Sedan, Automatic, 125C/MD9 takes P185/75R14; the Base, 2D Coupe, Standard takes P185/75R14; the Base, 2D Coupe, Automatic, 3T40/MD9 takes P185/75R14; the LE, 2D Convertible, 3.1 T, Automatic, 125C/MD9 takes P185/75R14; the Base, 4D Sedan, Standard takes P185/75R14; the Base, 4D Sedan, Automatic, 3T40/MD9 takes P185/75R14; the GT, Automatic, 125C/MD9 takes P205/60R15; the GT, Automatic, 3T40/MD9 takes P205/60R15; the GT, Standard takes P205/60R15; the LE, 2D Convertible, 2.0 K, Automatic, 3T40/MD9 takes P185/75R14; the LE, 2D Convertible, 2.0 K, Standard takes P185/75R14; the LE, 2D Convertible, 2.0 K, Automatic, 125C/MD9 takes P185/75R14; the LE, 2D Convertible, 3.1 T, Automatic, 3T40/MD9 takes P185/75R14; the LE, 2D Convertible, 3.1 T, Standard takes P185/75R14; the LE, 2D Coupe, 2.0 K, Automatic, 125C/MD9 takes P185/75R14; the LE, 2D Coupe, 2.0 K, Automatic, 3T40/MD9 takes P185/75R14; the LE, 2D Coupe, 3.1 T, Automatic, 125C/MD9 takes P185/75R14; the LE, 2D Coupe, 3.1 T, Automatic, 3T40/MD9 takes P185/75R14; the LE, 2D Coupe, 3.1 T, Standard takes P185/75R14; the LE, 2D Coupe, 2.0 K, Standard takes P185/75R14; the LE, 4D Sedan, 2.0 K, Automatic, 125C/MD9 takes P185/75R14; the LE, 4D Sedan, 2.0 K, Automatic, 3T40/MD9 takes P185/75R14; the LE, 4D Sedan, 2.0 K, Standard takes P185/75R14; the LE, 4D Sedan, 3.1 T takes P185/75R14; the SE, 2.0 K, Automatic, 125C/MD9 takes P185/75R14; the SE, 2.0 K, Automatic, 3T40/MD9 takes P185/75R14; the SE, 2.0 K, Standard takes P185/75R14; the SE, 3.1 T, Automatic, 125C/MD9 takes P185/75R14; the SE, 3.1 T, Automatic, 3T40/MD9 takes P185/75R14; the SE, 3.1 T, Standard takes P185/75R14, per the factory service manual.
Factory-Spec Tire Size
Varies by trim
Base, 2D Coupe, Automatic, 125C/MD9: P185/75R14
Base, 4D Sedan, Automatic, 125C/MD9: P185/75R14
Base, 2D Coupe, Standard: P185/75R14
Base, 2D Coupe, Automatic, 3T40/MD9: P185/75R14
LE, 2D Convertible, 3.1 T, Automatic, 125C/MD9: P185/75R14
Base, 4D Sedan, Standard: P185/75R14
Base, 4D Sedan, Automatic, 3T40/MD9: P185/75R14
GT, Automatic, 125C/MD9: P205/60R15
GT, Automatic, 3T40/MD9: P205/60R15
GT, Standard: P205/60R15
LE, 2D Convertible, 2.0 K, Automatic, 3T40/MD9: P185/75R14
LE, 2D Convertible, 2.0 K, Standard: P185/75R14
LE, 2D Convertible, 2.0 K, Automatic, 125C/MD9: P185/75R14
LE, 2D Convertible, 3.1 T, Automatic, 3T40/MD9: P185/75R14
LE, 2D Convertible, 3.1 T, Standard: P185/75R14
LE, 2D Coupe, 2.0 K, Automatic, 125C/MD9: P185/75R14
LE, 2D Coupe, 2.0 K, Automatic, 3T40/MD9: P185/75R14
LE, 2D Coupe, 3.1 T, Automatic, 125C/MD9: P185/75R14
LE, 2D Coupe, 3.1 T, Automatic, 3T40/MD9: P185/75R14
LE, 2D Coupe, 3.1 T, Standard: P185/75R14
LE, 2D Coupe, 2.0 K, Standard: P185/75R14
LE, 4D Sedan, 2.0 K, Automatic, 125C/MD9: P185/75R14
LE, 4D Sedan, 2.0 K, Automatic, 3T40/MD9: P185/75R14