I am thinking about getting C5 thick spoke wheels that are 17x8.5" front and 18x9.5" rear. The front tires are 275/40ZR17 and the rears are 275/35ZR18. Will these be able to fit, without modification? I have heard someone say having different size rims front to back will mess up our suspension geometry, could someone explain this to me if it is true? Also I'm going to run 2.25" spacers all around. Any suggestions. Or should I just get some ROH snypers or something else that fits on our cars?

I think that 275 tires won't fit in the front. I might be wrong, but I always heard that 255 was the widest. Either way it will steer hard. My car with 255 in the front tracks all over the road.

Oooh its gonna look sweet with those C5 wheels. To fit that wide of a tire in the front you will definately have to cut some of the fenderwell. I plan to run 17x8.5 wheels with 255/45/zr17 tires witch will require fenderwell modification. As far as messing up the geometry of the suspension, as long as the diameter of all the wheels are the same then you should be fine. For example a 17 inch wheels with 45 series tire compared to a 18 inch wheel with 40 series tire both have the same diameter so it works out. I would recommend you run 255/45/zr17 in front and 275/40/zr18 in back (you could also run 40 series front / 35 series rear but you are more likely to damage the wheel on harsh bumps) Also I would not recommend you run spacers if you're going to be racing ... but if its just for daily driving then it should be OK. If you're gonna race then you want a direct bolt on fit wheel.

i had 275's all around and i only had a "slight" rub when i had the steering wheel turned all the way

thanks for all the help guys. The only thing is the tires have a lot of tread on them so I don't want to get rid of them for other tires. Would 2.25" spacers all around work good?

I just bought a set of those for my 91 Z and am waiting for the tires for them. I'm using a 245/45/17 on the front and a 275/35/18 on the back. I guy that I know has the same rims on his at http://www.sphosting.com/jays91z28. I payed like $1100 for my rims. Thinking about selling them for what I payed for them though. Not sure if i'm gonna keep the car. If anyone's interested, just email me at bigm@caraudio.com

You can run 2-1/4" all around but I don't recommend them on the rear if the car is lowered since the rear tire will be even with the rear fender.
Here is a pic of my car with 17x9's with 275/40/17 tires with 2-1/4" spacers on the rear,

so if i get 17x8.5-9 c5 corvette rims all around do i need spacers and how bout front rotors do they fit with the stocks 1s

275 width tires fit in the front with the right offset/spacers, no problem. Thing is that you need a 9.5" wheel to do it right, otherwise the tire's sidewall is going to be bulging out.

I have a set of stock C5 wheels on my car. 17" front, 18" rear; stock size tires, whatever those are, can't recall off the top of my head; 2" adapters all the way around; fits fine.

Won't work without adapters. (that's what you reall need, a "spacer" would use long studs and you DON'T want that) The offset / backspacing is WAY too wrong to work without them.

245/45-17, 275/40-18 on stock C5 wheels. 2" spacers front and rear...
very nice