I had a hard time deciding on wheels for my G8. I found these and had to give them a try.
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C6 Z06 wheels bolt patter is 5x4.75(120.65)
Fronts are 18x8.5 ET56
Rears are 19x10 ET79
I decided to play it safe and buy adapters to go from 5x4.75 to 5x120 not just spacers to get the right offset. Adapters are 24 mm thick. If I did it again I would probably go somewhere between 27 and 30 in the rear.
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I had to cut the front stock lug stud to 1 1/8 inch from disk face to tip of stud for the wheels to mate to the adapter. The rears I cut a half inch off of. I will confirm but I think total length is also 1 1/8 inch.
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Currently running 245/40/18 in the front and 285/35/19 in the rear. I will go to a 245/45/18 and would like to go to 295/35/19. As mentioned earlier I am not sure there is room for a 295 at this offset on the inner fender side.
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I think it would look better a little lowered but not unhappy with it now.
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