There are two different methods for measuring wheel offset, the back-space method and the centre-line method, which is the most common. This takes a measurement from the wheel’s true centre line to the hub mounting face, giving you either a negative or positive measurement. If you’re lucky there will be a set of stampings on the inside of the wheels indicating the PCD (explained below) and the offset. The offset with be a number accompanied by either ET, P or just the measurement (as shown) to indicate a positive offset. Alternatively, a negative offset is shown by -ET, N or (-). These markings are common on one-piece wheels, but on two- or three-piece wheels you will likely have to measure it yourself.