does anybody know the tire size i would need for 17x9.5 and 18x10.5 (ZO6 rims). i need to price the tires and i know very little about the tire sizes and making them match up. thanks for any help.

 

if you want what the z06 uses- 265/40/17 up front and 295/35/18 out back although, with a 9.5 inch wide wheels, a 275/40/17 can fit up front

 

so the 275's will fit up front? if so the main question that i have left is what size will make the tires look most even. i know that can be kinda tricky with different rim sizes.

 

I've got 275/40/17 on 17x9.5 all the way around and they fit fine. Maybe this tire calculator will help you.
Tire calc

 

why would you try making them look the same size....that defeats the purpose of going with 18s in the back doesnt it?

 

my buddy works in a tire shop and he told me it would affect ride hieght.

 

You generally want to keep the tire diameter close to the stock size. That minimizes the impacts on the speedometer, loss of gear ratio, upsets to suspension geometry and raising the ride height that you will encounter by going to a significantly larger diameter tire in the back. Not many people like a "rake", with the back end higher than the front.

That said, as noted above 275/40-17 for the front is identical to stock tire size on the WS6/SS models, and same outside diameter as the 245/50-16's that came on most of the other LT1's. The Z06 17x9.5" offset is 54mm, which is almost identical to the stock 16x8 55mm and 17x9 55mm wheels.... no problem with "fitting".

In the back, the 18x10.5 Z06 wheel has a 58mm offset, and that yields almost an 8" backspace, so you are going to have **possible** problems with the tire rubbing on the inner fenders. The 17x11 ZR1's are only 7.93" backspace.

As far as tires, to match the diameter, use a 275/35 or 285/35-18. One is slightly smaller than stock diameter, and the other is slightly larger. The 285 would probably "look" the best.