1979 Pontiac Grand Am tire and wheel sizes, bolt pattern and tire pressure

Check the tables below for every tire size, wheel size, bolt pattern (PCD), rim offset and tire pressure fitted to the 1979 Pontiac Grand Am.

1979 Pontiac Grand Am tire sizes

225/70R15

Bolt pattern

5x120.65

Other years

1973 1974 1975 1978 1979 1980 1985 1986 All 1972–2005

Fitment tables

4 trims sold in 1979

Open a trim for its factory package and every alternative size, front and rear.

Pontiac Grand Am G-body

1978 – 1980 USA market 4 trims

Grand Am 3.6

110 hp · V6 225/70 R15 1 fitment

GenerationG-body 1978–1980

Power110 hp

EngineV6, Petrol

Center bore70.3 mm

PCD5x120.65

Thread7/16" - 20 UNF

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

Grand Am 4.9 2-bbl

139 hp · V8 225/70 R15 1 fitment

GenerationG-body 1978–1980

Power139 hp

EngineV8, Petrol

Center bore70.3 mm

PCD5x120.65

Thread7/16" - 20 UNF

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

Grand Am 4.9 4-bbl

156 hp · V8 225/70 R15 1 fitment

GenerationG-body 1978–1980

Power156 hp

EngineV8, Petrol

Center bore70.3 mm

PCD5x120.65

Thread7/16" - 20 UNF

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

Grand Am 5.0 4-bbl

160 hp · V8 225/70 R15 1 fitment

GenerationG-body 1978–1980

Power160 hp

EngineV8, Petrol

Center bore70.3 mm

PCD5x120.65

Thread7/16" - 20 UNF

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

Reading the table

What these columns mean

OE fitment: The package fitted at the factory for that trim.
Alternative: A size the car accepts without modification — plus-sizing, winter setups or optional wheels.
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.
Staggered: A wider tire on the rear axle than the front. Front-to-back rotation is not possible.
Thread size: Lug bolt or nut thread — needed when buying aftermarket fasteners.