Planning on getting a new set of wheels but I'm not sure of the correct spacing. My car is a 91 Z-28, and I plan on "downgrading" to 15" rims, 15x8 actually. Also what size tire will I need to run to keep the speedo and other gauges happy? Or just point me in the right direction if this is all listed on someones site. Thanks.

 

I believe you want 4" backspacing, but don't take my word for it. The stock 245/50/16 tires are about 26.4" tall, so look for a 15" tire close to that and your speedo should be close.

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87 Formula 350 13.94@96.67
98 Z28 1LE 13.15@107.59
1LE Owners Association

 

245/50-16's are about 25.6" tall.

This is also the height of 225/60-15's(fronts?)(will need a 15x7 wheel) and 265/50-15's(rears?)(need a 15x8.5 or 15x9 wheel)

1" = 25.4mm

 

You can to a maximum of 5.5" backspacing so whatever you feel will look better on your car with an 8" rim.

 

sweet, thanks to all who replied.