Hello All - I know in the past I have come accross the answer to my question, but I have searched for 30 minutes and not found it yet...

I have 18 x 10.5 C5 rear rims and 17 x 9.5 C5 front rims, can I place those on a 99 Trans-Am without any rubbing issues? Please let me know, I have had them sitting here for years.

 

For the rears, the 10.5 the offset must be between +38 to +50 mm .... 285, 295, 305, 315 are the tire width you can use. And the fronts need to be between +38 to +56 mm offset.... 255, 265, 275, 285 tire width. Otherwise you will more than likely run into problems, why dont you just take a tire off and try the other rims on it?

 

See this post:
http://web.camaross.com/forums/showthread.php?t=648039

Looks like you might have some rubbing issues but nothing major.
I still need to get tires for my wheels to know for sure and due to work, I won't have time for at least another month. If you get yours on, post up and let me know how it went.

 

Are they Z06 C5 wheels? That's the only C5 that had 18x10.5" wide wheels from the factory. They are 58mm offset, and the inside edge of the tire is going to be close to the inner fender liner, and the jounce bumper bracket may catch on the inside edge of the rim when you jack the car up.

Ditto with the fronts. 17x9.5's were only used on the Z06. Offset is 54mm, so they will not cause any problems in the front.

If they are aftermarket C5 wheels, which were available in 18x10.5" and 17x9.5" sizes, you have to know the offset to determine if they will fit on a 4th Gen without interference.