Offset is the term used for two different measurements related to the running gear of a vehicle.
In a steering system, offset is the distance between the centre of the tyre contact patch and the point where the steering axis hits the ground. This is also known as steering offset or scrub radius.
In wheel design, offset is the distance between the centre plane of the wheel and the mounting face which sits flush against the wheel hub. If the mounting face is inboard of the wheel's centre plane, the wheel has positive offset (also known as outset). If the mounting face is outboard of the centre of the wheel, there is negative offset (also known as inset).
