I have an old set of Halibrand 15 by 7.5 inch magnesium wheels that I want to put on my 68 coupe. The backspacing is about 4 7/16, seems wheels are about zero offset (total width is about 8 5/8 inch, with 7.5 inch bead to bead). Wheels have 5 by 5 inch bolt pattern, don't want to redrill wheels or hubs. Was considereing using some 1 inch thick billet 5 by 4 3/4 to 5 by 5 inch adapters. By my calculations, with the adapters, the inside of the wheel would be about 1/2 inch out from the stock 8 inch rallye (with 4 inch backspacing), and the outside of the wheel would be at about the same location as on the stock 8 inch rallye. This should mean that the tire itself ends up about 1/4 inch closer to the fender lip (because it will center itself in the wheel, even though the outside bead is in about the same location as on the stock 8 inch rallye). Really, this might be more like 3/8 inch closer to fender lip, because backspacing is 1/16 short of 4.5 inches, and rim is about 1/16 thicker from edge to bead than the rallye wheel. My question is whether this 3/8 inch closer to the fender lip will make a difference in what size tire I can use. I have read that you can go to 255/60 15s with the 8 inch rallye (migh have to size down in front for clearance)--could I get by with the same size with the Halibrand set up I'm considering, or would I have to reduce size (3/8 inch is almost 10 centimeters, this might mean the difference between a 255 and a 235 tire if clearance will be compromised)? Thanks for any input.

 

Hmmmm, how about a pic or two of those wheels… and let me know if you decide to sell them.