Backspace is the distance in inches from the edge of the rear flange to the mounting pad.
Offset is the distance in millimeters from the wheel's imaginary centerline to the mounting pad.
Here's a handy offset to backspace conversion chart:
Backspace is the distance in inches from the edge of the rear flange to the mounting pad.
Offset is the distance in millimeters from the wheel's imaginary centerline to the mounting pad.
Here's a handy offset to backspace conversion chart: