Measuring your bolt/lug pattern can be simple and can also be a little tricky. Many of the Lug Patterns used today are 5 lugs, these can be tricky because your actualy trying to measure the diameter of an imaginary circle. Most people in the tire/wheel industry would tell you to just measure from the center of one bolt to the back side of the bolt across from it. Another method would be to measure from the center of one bolt to the center of the bolt across from it and multiply by 1.05. You could also use a tool like the Bolt Pattern Pro this will give you the most accurate measurement.
This sticker was located in the drivers door jamb of my Ford F-150. I used this to help me with my larger rim selection. Since my OE width was 7.0in. I used a rule of 2.0in. over stock, so 9.0in. wide is my max. This helped me determine how large a diameter wheel I could upgrade to 24's or 26's, any larger and the width would increase to 10in. and would not turn correctly. I chose 24's because back in 2004 26's were a $10,000+ wheel/tire package.