Remove the wheel from the vehicle
Place the wheel face down on a flat surface
Measure the wheel width from bead seat to bead seat
Divide the wheel width by 2 to find the centerline
Measure from the mounting pad to the straightedge across the wheel
Compare the mounting pad distance to the centerline
If the mounting pad is toward the outside face, the offset is positive
If the mounting pad is toward the inside face, the offset is negative
Record the offset in millimeters
Use a wheel offset gauge if available for a direct measurement