• Welcome to the Pontiac Trans Am Community, the Official Home of the PTA! Sign up for a (FREE) account today!

My Dilemma With New Rubber On A 76 TA With Stock Suspension

Seventy6er

Well-known member
Joined
Dec 5, 2022
Messages
73
Reaction score
131
Points
33
Location
Dixie
So I keep getting myself in a mental corner when trying to pinpoint "the perfect combo" to fill out the 76 with new shoes on 15x8 wheels (currently all stock 15x7s).

I've come across a modest consensus that 255/60/15 on all fours is overall pleasing, but I also discovered some who've adopted rears in 265 in 60/15s (heck, even 275/50/17s).

I don't plan on modifying the suspension anytime soon.

I want to fill her out a bit, maybe (or maybe not) with a half to 1 or 1.5-inch diameter difference for the rear to create a very subtle old-school posture and not anything low-profile pro-touring.

Any info, pros, cons, images, general advice, etc., would greatly help reduce the agony of sifting through the endless pit of Google - LOL.

Thanks, guys.
 

rnla

New member
Joined
Jun 10, 2021
Messages
3
Reaction score
3
Points
3
Location
Benton, LA
My 79 10th Ann edition came new with 225/70R15 on 15x8 wheels. I have BF Goodrich raised white letter Radial T/A s in the same size on it and they look great. No more power than these cars have there's little reason to put bigger rubber on them unless you just feel so led which you obviously do. I staggered the tire size on my '65 Mustang that I recently sold and I liked the look, but there's no rotating tires if you drive your car much if that matters to you. Also, if there are any clearance issues front to rear you have to consider your spare tire size if you carry a full size spare. My car came with the inflatable spare and air bottle (which I still have) but would be scared to use for obvious reasons. When you buy your wheels, make sure there's not a backspace issue. An inch or inch and a half of additional width can be problematic, especially if it's all on one side of the wheel, i.e. the extra width is all or mostly to the outside or inside. It depends on how the wheel is built. As I'm sure you are aware, there are wheels that have the mounting flange in the center-line of the wheel and those that are on the extreme outside like most cars now, and those on the extreme inside like the old chrome reverse wheels popular in the early 60's. Some tire/wheel modification options require spacers to make them fit properly. This can change the design geometry of the suspension and steering. You can see how that could be the case. Whether it matters or not, whether it's safe or not is a subject for guys smarter than me, but we have to at least consider these things if we're going to zip down the highway in a 3700# 45 year old vehicle. Buying non-stock wheels and tires that fit can be agonizing. I probably gave you more questions than answers, but I hope something in here is useful. Good luck on your project.
 

Seventy6er

Well-known member
Joined
Dec 5, 2022
Messages
73
Reaction score
131
Points
33
Location
Dixie
Thanks - and I've since opted for a slight stagger to the front and rear rubbers on 15x8 Snowflakes, and the clearances are outstanding all around.

I initially figured this change from the original 15x7s and 235s would give it more teeth and give me the time to upgrade later, but I think I'll stick with the current upgrade (photo).

To see how she sits on the ground, go to: https://www.pontiactransamforum.com...nough-to-post-my-76-ta-still-work-ahead.1844/

76TireWheelCombos.jpg