100-S Classic Series Charcoal Gray aluminum car wheels with machined lip. Licensed from American Racing (wheel design is a trademark of American Racing LLC). High quality one-piece cast aluminum alloy rims. Powder coated and clear coated. Rim Size: 15x8", Wheel Lug pattern: Chevy / GM's 5x4.75" (same as 5x120.65mm), Wheel offset: 0mm, Wheel Backspacing: 4.50", Center bore size: 73mm, Required lug nuts (not included): 7/16 R.H. acorn (conical seat) for 1953-1981 GM cars with 5x4.75" lug pattern (Buick, Chevy, Oldsmobile and Pontiac) or 12x1.5mm R.H. acorn (conical seat) for 1982-1992 GM cars with 5x4.75" lug pattern (Buick, Chevy, Oldsmobile and Pontiac).