1978 Pontiac Grand Prix Wheel and Tire Sizes

Status
Not open for further replies.

Shelbywh89

Not-quite-so-new-guy
Oct 2, 2016
42
16
8
Hey, Guys
Looking for some help with picking the right size tires for my setup. I wanted to know if these wheel and tire size combo will fit with the 78 Grand prix. I was wanting to put 275x45x17 on the rear and wanted to know if anybody had done this with no mods

Front
17x8 4.50 Backspace
245x45x17 Tires

Back
17x9 5.250 Backspace
275x45x17 Tires
 

UNGN

Comic Book Super Hero
Sep 6, 2016
3,048
3,264
113
Southlake, TX
That back spacing is going to be close to the frame in back... real close. 4.5" BS with a 9" wheel would work better without a frame notch. I think 5.25 might need the frame narrowed a bit, and the required 3/4" spacers are a tough fit - too narrow for adapters/too wide for spacers.

8's with 4.5BS (about zero offset) should work OK in front with a 245 tire. The fender lip might need a little bit of a roll depending how low the front is.
 

Shelbywh89

Not-quite-so-new-guy
Oct 2, 2016
42
16
8
mmmm not good as I've already got the wheels. looking at buying the tires....
 

UNGN

Comic Book Super Hero
Sep 6, 2016
3,048
3,264
113
Southlake, TX
mmmm not good as I've already got the wheels. looking at buying the tires....


Have you bolted the wheels on in back? How much room do you have for tires? You'll need at least 3/4" between the inside of the wheel bead (where the tire mounts) and the frame to work with a 275/40 and 9" wide wheels. If you have more than 3/4"-1" you probably won't hit the frame with the tires. Less than 3/4" and it's gonna rub with a 275.
 
Status
Not open for further replies.

GBodyForum is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to amazon.com. Amazon, the Amazon logo, AmazonSupply, and the AmazonSupply logo are trademarks of Amazon.com, Inc. or its affiliates.

Please support GBodyForum Sponsors

Classic Truck Consoles Dixie Restoration Depot UMI Performance

Contact [email protected] for info on becoming a sponsor