newbielt1

I'm thinking about getting new wheels for my '94 Z, but I have no idea what any of the specs or measurements are, such as offset, backspacing, bolt pattern, etc. Also, does of any of the specs change if I was thinking of going with 17" or 18" wheels. It would greatly be appreciated if you guys can share some info. I apologize for my lack of knowledge in this subject area. Thanks in advance.

~~Wes

Injuneer

4th Gen wheel bolt pattern is same as the 3rd Gen.... 5 lugs on a 4.75" (120.65mm) bolt circle. Wheel studs are 12mm X 1.5 pitch.

Stock wheels are 16x8", with a 55mm offset, giving them a backspace of about 6-5/8". Stock wheels on SS and WS6 coupes are 17x9", with a 55mm offset, and about a 7-1/8" backspace.

Offset and backspace determine where the wheel sits in the wheel opening, with respect to the outside of the fender. It will not change based on wheel diameter, only based on wheel width.

The most popular wheel size for upgrades is the 17x9.5" or 18x9.5". In those sizes, you generally want the offset in the range of 45-56mm (7.00" - 7.42" backspace). That is pretty much the widest wheel you can fit in the front, although I have actually seen 17x11's on an Auto-X car, but it looks kinda dumb.... .

The widest wheel that will fit in the back is a 17x11. Recommended offset is 50mm (7.93" backspace). Any less offset, and the tire/wheel profile extends beyond the outer edge of the fender. Any more offset, and the inner edge of the tire is deep into the inner fender. Even with the 50mm offset, some people have to hammer the inner fenders slightly, or cut thr corner off the jounce bumper brackets. But is seems to vary quite a bit from car to car.

As far as tires, the stock tire diameter is 25.66". That is the size of the 245/50-16 that was the high perf tire on the base LT1's. And it is also the outer diameter of the 275/40-17 that was used on the SS/WS6's. A 315/35-17 fits on the 17x11, and also has the same 25.66" outside diameter. If you go to an 18" wheel, you need to look at 275/35-18 or 285/35-18 to get close to the stock tire diameter.

For drag wheels, you either want a 15x8" with 5.5" backspace, or a 15x10" with 7.5" backspace. Those sizes will fit most popular DOT slicks, and keep them under the fender. Many 15" wheels will require grinding the fins off the brake calipers.

17x9.5 (56mm) front; 17x11 (50mm rear)

17x9.5 (49mm) all around

15x3.5 front, 15x10 (7.5BS) rear, 28x10.5-15W tires