Below is a link to a calculator, useful to see how much a rim will stick out, (or in), more than your OEM rims.
You only need to know the width and offset of your current rim and the rim under consideration. Btw, it uses the nominal width, that can usually be read from the inside of a rim ... such as on the spare. If you measure an 8" rim it will be closer to 9 inches, because of the lips. Most calculators and wheel dealers use the smaller nominal width. The offset of th wheel is also usually stamped on the wheel near the nominal size.

http://www.americanracing.com/techcenter/OffsetCal culator/offset.html

The attachments shows an example of the input and output of the calculator.
The first attached thumbnail show a 7.5" rim as the current wheel and an 8" as the new wheel. Notice the results, in the second thumbnail. The inside clearance is only 1 mm different ... both rims, (because of different offsets), basically have the same backspacing, (distance from the outermost edge of the back side of the wheel to the mounting surface).

The goal is usually to try to stay close to the OEM backspacing when picking new wheels. More backspacing and the wheel or tire might rub the strut, spindle, or steering knuckle ... less backspacing and the wheel sticks out too far and can cause tire to fender rubbing while turning the steering wheel.

If you have an 8" rim, its numbers would be entered into the current wheel and the rim you are considering, (for example, maybe an 8.5" rim with +18mm offset), might be entered into the new wheel fields.

Found this information at http://www.titantruckz.com/showthread.php?t=119 but it is more Nissan Titan specific over there.

Attached Images

	offsetOEMi.jpg (30.3 KB, 25 views)
	offsetOEMo.jpg (19.0 KB, 15 views)

Couldn't get that one to work, but found another. Do you know what the stock offset is? I thought 35mm.

Wheel Offset Calculator

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