I want to get some C6 Z06 rims but i want to know what the biggest size i can run without spacers or clearance issues.

Which combo can i run?

17 x 9.5 all around
18 x 8.5 all around
18 x 9.5 40mm offset all around
18 x 9.5 Front/ 18 x 10.5 Rear

 

You can run any of the combos that you listed. Just make sure that the offsets are correct for your vehicle as F-Bodies and Vettes run different offsets. In the 17x9.5 setup, the stock offset is 57mm. I wouldn't recommend using a wheel wider than 9.5 for the front. For the rear, if you want to go with the 18x10.5 setup, a 56mm offset should work well without the need for spacers or any modifications. If you search on this forum, there are a few threads that should guide you in your endeavors. As for tires, you will find that 18" tires are significantly more costly than their 17" counterparts so that may be a consideration as well. Good luck and hope this helps.

 

There are guidelines in the FAQ for wheel width vs. offset for 4th Gens. A 10.5" wide wheel will work best with no more than a 52mm offset. That provides roughly a 7.75" backspace, which will be interference free. The closer you get to 8.00" backspace (e.g. 58mm used on the stock C5 Z06 wheels) the more likely you will have rubbing on the inner fenders with a wide tire, problems with the edges of the jounce bumper brackets, etc.

I like the 9.5's with a 45-56mm offset. 40mm will move them a bit toward the outside of the fenders in the front. The closer you get to the outside, the more likely a large diameter tire or wide tread tire will rub on the plastic inner fender liners with the wheels at full lock.

Stock 4th Gen V8 model wheels are either 16x8.0 55mm, or 17x9.0 50mm.

 

I thought the 18 x 9.5s were available also with a +56.

 

According to the data I've seen, the factory C6 Z06 front wheels are 18 x 9.5" 50mm offset.

 

I just checked ,you can get them with a +56 offset in a OEM reproduction wheel.

 

I have those wheels by OE concept on all 4 at 18x10.5.. Required some slight mods to rear fenders... All at 44mm.. For $780 quality is great.