I want to put 97-99 c5 wagon wheels on my 87. 18" wheels all four corners. Stock 87 wheels are 32mm ofset. c5 wheels are 56mm? Differance is 24mm or .994 inches. Is a one inch thick adapter what i need?
Actually that's backwards. On 84-87 you will use them for them to sit right, on 88-up non needed. You can run them without to be sure buy they sit into the wheel well, not flush. IT's all personal preference at that point.
I think that's what Dan85Vette meant, just not clear from the posting.
One thing that hasn't been mentioned is the original posters calculation that he needed a 1" adapter. If you do the math just on the spacing then 1" is correct, however you also have to take into account that the wheel is going to be wider, so if you move it out 1" and then have a wider wheel you will probably be sticking out some. I have 3/4" adapters on my 85 using 1990 wheels and they fit great.