I'm buying a set of 2- 19x8.5" front wheels with 245/35zr19"s and 2 19x9.5" rear wheels with 275/30zr19"s

would i be alright with a 20mm front offset and a 30mm rear offset?

or should i go with a 38mm offset for both front and rear? i want the tires to almost line up with my fenders but not rub on them

what kind of backspace would i need with any of the above offsets?

 

With the 8.5" wide/20mm offset, and the 9.5" wide/30mm offset, you will be pushing the limits, possibly putting the tires outside the fenders.

The 9.5" in the back will be just barely under the edge of the fender like my 17x11's... maybe just a bit farther out, since the Camaro fenders don't seem to bulge as much as the Firebird fenders. A 38mm offset would move them about 1/3" under the fender line.



The 8.5" in the front will have a similar "front space" (3.92"), quite likely putting it outside the fender line. The front wheel in the picture below has a 3.32" front space. The 20mm offset would move the outside edge of the wheel out more than 1/2" more than the wheel in the picture. With a 38mm offset (3.21"), it would be very close to what is in the picture.

 

i found a better set of wheels. 19x8.5's front and back. 38mm offset on both. and i'm going to put 275/30zr19's or 275/35zr19's

my rear fenders are already made to fit my 335 tires on my 11" wide zr1's

if this setup sounds like a good idea to you then i'm going to order them today

thanks for your help