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Wheel offset (ET) guide

# 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).

## More tools

- [Wheel offset (ET) decoder](https://tirefitlab.com/wheel-offset-calculator/)
- [Bolt pattern guide](https://tirefitlab.com/learn/bolt-pattern/)
- [Rim diameter guide](https://tirefitlab.com/learn/rim/)
- [Plus sizing guide](https://tirefitlab.com/learn/plus-sizing/)
- [Tire & wheel reference guides](https://tirefitlab.com/learn/)

[Last reviewed: 2026-06-21](https://tirefitlab.com/methodology/)

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## Planning a long summer drive?

Use the budget and running-cost tools before a trip, especially if the current tires are worn or the replacement size changes diameter.

[Estimate tire budget](https://tirefitlab.com/tire-budget-calculator/)

## More in this topic: Wheel fitment depth

Rim, offset, spacer and bolt-pattern guides for physical fitment checks.

- [**Bolt pattern guide** Find which bolt pattern your car uses and which wheels are compatible. PCD tables for 4x100, 5x112, 5x114.3 and more.](https://tirefitlab.com/learn/bolt-pattern/)
- [**Rim diameter guide** Find which tire sizes fit each rim diameter from 14 to 22 inches.](https://tirefitlab.com/learn/rim/)
- [**Rim types and materials guide** Rim types explained: steel stamped, cast aluminium alloy, flow-formed alloy, forged alloy, carbon fibre. Weight comparison, heat dissipation, repair cost, corrosion resistance, and which type suits which driving application.](https://tirefitlab.com/learn/rim-types/)
- [**Rim width and tire fitment guide** Use an editorial rim-width screening chart, then verify the approved range for the exact tire product, vehicle clearance and wheel specification.](https://tirefitlab.com/learn/rim-width-tyre-fitment/)

### Useful tools

[Wheel offset (ET) decoder](https://tirefitlab.com/wheel-offset-calculator/)[Staggered tire setup calculator](https://tirefitlab.com/staggered-tire-calculator/)