The tires are 15*8 in the rear and 15*3 1/2 in the front. The lug nuts are 1/2" lug studs. The lug pattern is 5 on 4 3/4. - The fronts are 1 3/4" and the rears are 5 1/2" cause they are 15x3.5 front and 15x8 rear - would these fit on my IROC, or do I need anything else as well?

 

are those numbers the backspacing? front should be fine, the rear should be 4.5". 5.5 will work, but will put the wheel firther in than stock, and if you use a wide tire, you could have rubbing issues.

the stock wheel studs are 12mm1.5 BTW, not 1/2". and the bolt pattern in 5x4.75

 

yes those are the backspacing numbers. The tire is a 275 tire on them. will that cause rubbing you think? i wonder if there are any pictures of 5.5 backspacing on the iroc ... time to search methinks!

 

The Weld Pro-Stars are my favorite. I hope you can make it work.

 

ProStars look great on these cars....I originally wanted to run a set of them on mine, but found a nice set of used DragLites for cheap.....