What is wheel offset (ET)?
Offset (commonly written as ET from the German Einpress Tiefe) is the distance in millimetres from the wheel's centreline to its hub-mounting face — the flat surface that presses against the hub.
Positive, zero and negative offset
- Positive offset (e.g. ET40): the mounting face is in front of the centreline → the wheel sits further inward. Most common on passenger cars.
- Zero offset (ET0): the mounting face is exactly at the centreline.
- Negative offset (e.g. ET−15): the mounting face is behind the centreline → the wheel protrudes further outward. Typical of off-road vehicles and wide-body fitments.
Example
An 8-inch wide wheel has a total width of 8 × 25.4 = 203.2 mm, so the centreline is at 101.6 mm. With ET35 the mounting face sits 35 mm in front of the centreline; the wheel extends 66.6 mm inward and 101.6 mm outward.
How much deviation is acceptable?
A common rule of thumb allows ±5 mm from the original ET without issues. Larger deviations can cause:
- Contact with wheel arches, brake calipers or suspension components
- Altered steering behaviour (scrub radius changes)
- Increased load on wheel bearings and suspension
Always verify exact specifications for your vehicle and consult a wheel specialist if in doubt.