The 1990 Nissan Pickup tire size depends on trim: the Base, 2D Pickup Extra Cab, 4WD takes LT195/75R14 B; the Base, 2D Pickup Extra Cab, RWD, Automatic takes LT195/75R14 B; the Base, 2D Pickup Extra Cab, RWD, Standard takes LT195/75R14 B; the Base, 2D Pickup, 2.4 S, 4WD takes LT195/75R14 B; the Base, 2D Pickup, 2.4 S, RWD, Automatic takes LT195/75R14 B; the Base, 2D Pickup, 2.4 S, RWD, Standard takes LT195/75R14 B; the Base, 2D Pickup, 3.0 H, 4WD, Automatic takes LT195/75R14 B; the Base, 2D Pickup, 3.0 H, 4WD, Standard takes LT195/75R14 B; the Base, 2D Pickup, 3.0 H, RWD, Automatic takes LT195/75R14 B; the Base, 2D Pickup, 3.0 H, RWD, Standard takes LT195/75R14 B; the SE, RWD, Standard takes P215/75R14; the SE, 4WD, Automatic takes LT195/75R14 B; the SE, 4WD, Standard takes LT195/75R14 B; the SE, RWD, Automatic takes P215/75R14, per the factory service manual.
Factory-Spec Tire Size
Varies by trim
Base, 2D Pickup Extra Cab, 4WD: LT195/75R14 B
Base, 2D Pickup Extra Cab, RWD, Automatic: LT195/75R14 B
Base, 2D Pickup Extra Cab, RWD, Standard: LT195/75R14 B
Base, 2D Pickup, 2.4 S, 4WD: LT195/75R14 B
Base, 2D Pickup, 2.4 S, RWD, Automatic: LT195/75R14 B
Base, 2D Pickup, 2.4 S, RWD, Standard: LT195/75R14 B
Base, 2D Pickup, 3.0 H, 4WD, Automatic: LT195/75R14 B
Base, 2D Pickup, 3.0 H, 4WD, Standard: LT195/75R14 B
Base, 2D Pickup, 3.0 H, RWD, Automatic: LT195/75R14 B
Base, 2D Pickup, 3.0 H, RWD, Standard: LT195/75R14 B