Offset and Backspacing
When you bought your vehicle from the dealership, engineers have put long hard hours to calculate a wheel and tire combo that would work well with the vehicle. Calculating width, diameter, offset, rear spacing, offset, and much more. Most people think; "The bolt patterns are the same, let's bolt them up." That is where people finally find a problem. Some may fit, some may not, and some will look unsightly. Anyhow, those engineers designed a wheel that would distribute load evenly on the wheel bearings, clear the rotors and braking system parts, and also keep you from rubbing your frame or front bumper. So, well, how do you figure out which works best and what is what - just tell me what I need...