Offset describes the distance between the wheel’s mounting surface and its centerline, measured in millimeters. A higher positive offset tucks the wheel further into the fender; a lower or negative offset pushes it outward.
Bolt pattern refers to the number of lug holes and the diameter of the circle they sit on. Getting this wrong means the wheel simply won’t mount.
Backspacing works alongside offset to determine tire clearance against suspension components. All three measurements should be confirmed against the vehicle’s specification before a custom order is placed.