Custom Wheels 101: What are Wheel Backspacing and Offset?

The perfect set of wheels is an essential element of any classic car build, but choosing wheels isn't always as easy as it might seem. There are many technical variables that must be considered, including bolt pattern, diameter, width, backspacing, and offset. Once you've established the wheel specs you need, you'll have to shop for an appropriate set of wheels with an appealing design and finish. In this article, we'll provide some info and diagrams to help you answer the question "what are wheel backspacing and offset?"

W23 Recall Wheels

Once upon a time, one of Chrysler's wheel manufacturers came up with a cast aluminum wheel design that drew inspiration from magnesium wheels used on mid sixties Cobras. It was called the Cast Center Road Wheel and was offered as an option on various 1969 Mopar models under Sales Code W23.

Unfortunately, at that time, aluminum casting was a recent innovation and the process still had some issues. Some of the later development tests would show that the W23 wheels had a tendency to loosen the lug nuts, allowing the wheels to come off.