What does Offset mean?
Offset is the distance between the hub mounting face at the back of the wheel and the wheel’s center line.
Offset is usually stamped or engraved into the wheel and is measured in millimetres of ‘ET’ [ET is the short form of the German word ‘Einpresstiefe’ which literally translates as ‘insertion depth’]
Positive Offset wheels have their mounting face toward the front face of the wheel. Most front wheel drive vehicles have positive ET wheels.
Zero Offset wheels have their mounting face even with the center line of the wheel and are by definition “ET 0″.
Negative Offset wheels have their mounting face toward the rear of the wheel – powerful rear-wheel drive cars often have wheels with negative offset.
–Courtesy of YHI