Originally Posted by 8VETTE7

C6 and C7 wheels have the same offset specifications which are significantly different than the C5 offset specificatons so the same issues that exist putting C6 wheels on a C5 apply to putting C7 wheels on a C5.


Here is a table of wheel specs:

Backspace/offset dimensions are as follows:

C5 (coupe/vert):
Front 17x8.5", 58mm offset = 7.03" backspace
Rear 18x9.5" 65mm offset = 7.81" backspace

C5 Z06:
Front 17x9.5", 54mm offset = 7.38" backspace
Rear 18x10.5", 58mm offset = 8.03" backspace

C6 (coupe/vert):
Front 18x8.5", 56mm offset = 6.95" backspace
Rear 19x10", 79mm offset = 8.61" backspace

C6 Z06 and C6 GrandSport:
Front 18x9.5", 40mm offset = 7.22" backspace
Rear 19x12", 59mm offset = 8.82" backspace

C5 and C6 wheel circle:
5 on 4.75" (120.65MM)

Center hub dia. 70.3mm


Specifically to answer your question , you will likely need a 1/4" spacer on the rear wheels to just to keep them from rubbing the inner wheel well lining. Front wheels will work OK. Even with the 1/4" spacer (max you can run without installing longer studs) the wheels will appear sunk into the wheel wells. If you are OK with that appearance go for it. If you want the wheels to be flush or near flush to the rear fender as many C5 owners with C6 wheels want, then you will need about a 1" wheel adapter. Wheel adapters bolt to the factory studs and then have their own studs that the wheel mounts to.