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

Bolt pattern 5x120.65 on every 1978 trim.

Tires for the 1978 Pontiac Grand Prix

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

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

1978–1981 4 trims

Grand Prix 3.8 +3 variants N/A · V6 195/75SR14 2 fitments

Same tires and wheels on: 4.1, 4.3, 5.0

Check price on Amazon · 195/75R14 Wheels 14x6 ET8 · 5x120.65 · 70.3 mm on Amazon

Tire size	Rim size and bolt pattern	Pressure, psi
195/75SR14	Rim 14x6 ET8 ~~5x120.65~~	–
205/70HR15	Rim 15x6 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.