Wheel offset (ET) guide

What is wheel offset (ET)?

Wheel offset (ET from German Einpresstiefe = insertion depth) is the distance in mm from the wheel's mounting face to its centreline. Positive ET: mounting face is closer to the outside (most modern cars). Zero ET: mounting face is at the centreline. Negative ET: mounting face is closer to the inside (wide stance, off-road). The correct ET affects steering, clearance and bearing load.

Offset types at a glance

ET range	Type	Typical vehicles	Notes
ET 40–55	Positive (high)	FWD compacts, modern sedans	Flush or tucked wheels, minimal overhang.
ET 20–40	Positive (moderate)	Most AWD/RWD cars & SUVs	Balanced stance, stock look.
ET 0	Zero	Classic muscle cars, some trucks	Wheel face exactly at centreline.
ET −10 to −30	Negative	Off-road trucks, stance builds	Wide stance; check arch clearance.
ET −30 and below	Negative (extreme)	Dedicated off-road / show	Spacers or adapters often needed.

ET vs backspacing

ET is measured in millimetres from the mounting face to the centreline. Backspacing (used more commonly in North America) is the distance from the mounting face to the inner lip of the wheel. The relationship:

Backspacing (mm) = (rim width mm / 2) + ET

Example: a 225mm (8.86") wide wheel with ET 38 → backspacing = 112.5 + 38 = 150.5 mm (≈ 5.9").

How ET affects fitment

Too high ET (too positive) — wheel sits deep inside the arch. Inner sidewall may rub suspension or brake callipers. Rare on stock setups.
Too low ET (too negative) — wheel protrudes outward. Outer sidewall may rub the wheel arch liner. Increased scrub radius stresses steering geometry and wheel bearings.
OEM ET ± 5–8 mm is the safe range for most daily-driven cars without recalibrating ADAS or alignment.

How to read an ET stamp

The ET value is cast or stamped on the back of most alloy wheels, typically near the centre bore: ET38 or ET +38. Negative values appear as ET-15. Some manufacturers print it as Offset 38 or use the French abbreviation IS (Inset).

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Last reviewed: 2026-06-21