Offset & Backspace
The rim backspace is the distance from the back edge of the rim to the hub mounting surface. To determine
the rim backspace:
- Position the rim face down.
- Lay a straight-edge across the back of the rim. Measure the distance from the straight-edge to the rim's
hub mounting surface.
The rim offset is the distance from its hub mounting surface to the centerline of the wheel. To determine rim offset:
- Position the rim on a flat surface and measure its overall width.
- Divide the overall width by two, then subtract this result from the backspace value.
Offset = Backspace - (Rim Width / 2)
The offset of a rim can be one of three settings:
- Zero offset
- The hub mounting surface is even with the centerline of the rim.
- Positive offset
- The hub mounting surface is toward the front or wheel side of the wheel. Positive offset wheels are generally
found on front-wheel drive cars.
- Negative offset
- The hub mounting surface is toward the back or brake side of the wheel's centerline. "Deep dish" wheels are
typically negative offset.