Best fitment on 18 inch wheels

[Norwegianmopar]

So we are getting a set of custom wheels built for our ZR-1. It will be 18 x10 front and 18 x12 rear.

Does anyone have the ideal offset/back spacing to get the wheel as close to the fender lips as possible without risking too much rubbing?

Will the stock offset be the best (sharing the extra with on the in- and outside) or have you other experiences?

All tried and tested info is appreciated.20211101_165002.jpg

Sent from my SM-G955F using ZR-1 Net Registry mobile app

[Black Red '90]

I went 18 x 11.5" with a +41 offset in the rear. The outside lip of the wheel is dead-on with the center line of the car and the sidewall is just inside the center molding. The inner lip of the wheel is 1" away from the brake line with the sidewall 0.75" away. I wouldn't have wanted to be any closer, nor did I want any "poke." The size & offset was perfect for me.

(The fronts are OE size and offset.)

[Norwegianmopar]

This is what we landed on after doing some measurements and discussing what we are looking for:

Hi Roy!



Here is the fitment I am looking at for your 1994 Corvette ZR1. Please read carefully through the dimensions and notes below:



Stock:

Front - 17x9.5 +56 275/40/17

10.5" wide overall
7.45" of wheel from mounting surface to frameside - (BACKSPACE)
3.05" of wheel from mounting surface to fenderside - (FRONTSPACE)


Rear - 17x11 +36 315/35/17

12" wide overall
7.42" of wheel from mounting surface to frameside - (BACKSPACE)
4.55" of wheel from mounting surface to fenderside - (FRONTSPACE)
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3030 Autosport Series G

Front 18x10 +47 285/35/18 (.6" more wheel to fender, .10" less wheel to frame)

11" wide overall
7.35" of wheel from mounting surface to frameside - (BACKSPACE)
3.65" of wheel from mounting surface to fenderside - (FRONTSPACE)


Rear 18x12 +34 335/30/18 (.6" more wheel to fender, .4" more wheel to frame)

13" wide overall
7.85" of wheel from mounting surface to frameside - (BACKSPACE)
5.15" of wheel from mounting surface to fenderside - (FRONTSPACE)


Due to the maximum backspace possible in 2pc wheel construction, we are unable to achieve the offset "split" by moving the extra wheel widths inside and outside evenly. I have detailed the differences above.



Please confirm this will work for you before ordering. If you have any questions please let me know. I believe this set up will work, but it is best to confirm on your end.



IMPORTANT: Due to the age of the car please confirm caliper protrusion on the front brakes and rear brakes. Sometimes aftermarket replacements can have different dimensions. The wheels above will be set up with a .75" caliper clearance, meaning, the caliper face cannot exceed .67" of protrusion forward of the wheel's mounting surface. I have included our wheel measurement diagram and the dimension will be Dimension "C".



Thanks Roy, and I look forward to hearing from you!

[Black Red '90]

You'll have essentially the same backspacing as my wheels:

11.5" section width = 12.5" total width (6.25" to centerline)
41 mm offset /25.4 (metric conversion) = 1.61"
6.25" + 1.61" = 7.86" backspacing

Looking forward to pics once you've got them installed!