What is wheel offset ET?
Positive, zero and negative wheel offset and the limits of changing it.
Offset ET is the distance in millimetres between the rim centreline and the mounting face that contacts the hub.
Offset direction
- Positive ET: the mounting face is towards the outside; at the same rim width the wheel sits further inboard.
- ET0: the mounting face and centreline coincide.
- Negative ET: the mounting face is towards the inside; the wheel extends further outwards.
Calculation example
A nominal width of 8 inches is 203.2 mm. At ET35, the distance from the mounting face to the inner bead-seat edge is 101.6 + 35 = 136.6 mm; to the outer edge it is 101.6 − 35 = 66.6 mm. Overall rim width including flanges is greater than nominal width.
Can ET be changed?
There is no universal safe allowance of “±5 mm”. Check the particular vehicle, rim width, tyre, brakes, suspension, load and wheel manufacturer approval. Changing ET affects wheel position and steering geometry.