Will thirdgen GTA rims fit on my 1995 Formula? Is there any issues with thirdgen wheels fitting on a fourthgen car?

 

Nope.

You can stick 4th gen wheels on a 3rd gen with the use of high quality spacers but you can't stick 3rd gen wheels on a 4th gen. The wheels will stick WAY out!

 

Just to keep things in perspective, the 3rd Gen rear axle assembly is 3" narrower than the 4th Gen rear axle. That means the rear wheels on 3rd Gen's have about 1.5" less backspacing. If you put those wheels on a 4th Gen, you will move the outer edge of the wheel/tire about 1.5" further toward the outside of the car, compared to a stock 4th Gen wheels.

If we are talking 8" wide wheels, the 3rd Gen wheels would stick out about 3.75" from the face of the mounting hub. That would be about the same (maybe 1/4" less) than a GS offset 11" wide wheel. So, in the back, it would give the car a huge "stance" with some skinny wheels. But they wouldn't stick out any further than 11's.

I believe the backspace on the front 3rd Gen wheels may not always be the same as the rear wheels. I have seen a caution in some 3rd Gen manuals that indicates the front and rear wheels can not be interchanged.

 

Yep, I had a 3rd gen and the fronts and backs aren't the same. I can't remember which is which and I was always under the impression one pair of them would stick out significantly. It could be that only the front wheels would stick out if the backs would be like the 11" GS 4th gens?

 

The third gen 16" rims had 2 offsets. the fronts were not as deep as the rear.
I had 4 front 16" GTA wheels on my 86 and it looked very nice, gave it a wider stance in the rear.

I am now running 17x9.5 OZ Monte Carlos on my car. These are backspaced for a 4th gen, but I have a 4th gen rear and bolt on spacers on the front.