1978 Pontiac Grand Am tire and wheel sizes, bolt pattern and tire pressure

Bolt pattern 5x120.65 on every 1978 trim.

Tires for the 1978 Pontiac Grand Am

Sizes most trims come with first. Open your trim below for its exact size.

TireWheelGuide may earn a commission from purchases made through these links.

Open a trim for its tire and rim sizes, bolt pattern and tire pressure. Trims with the same tires and wheels share a row.

1978–1980 4 trims

Grand Am 3.6 +3 variants 110 hp · V6 225/70R15 1 fitment

Same tires and wheels on: 4.9 2-bbl, 4.9 4-bbl, 5.0 4-bbl

Check price on Amazon · 225/70R15 Wheels 15x7 ET8 · 5x120.65 · 70.3 mm on Amazon

Tire size	Rim size and bolt pattern	Pressure, psi
225/70R15	Rim 15x7 ET8 ~~5x120.65~~	–

What these columns mean

Rim size: Rim diameter × width in inches, and the factory offset (ET) in millimetres, e.g. 18x7.5 ET25.
Bolt pattern (PCD): Number of studs and the diameter of the circle they sit on. It must match exactly.
Center bore: Diameter of the hub hole. Larger aftermarket bores need hub-centric rings.
Pressure: Recommended cold inflation pressure for that axle, in psi.
Thread size: Lug bolt or nut thread — needed when buying aftermarket fasteners.