Disc offset (indicated as ET from German EinpressTiefe) is one of the key geometric parameters of the wheel, which determines the distance from the mating plane of the disk to its central axis. Even a minimal error of 3–5 mm can lead to accelerated wear of the wheel bearings, incorrect steering operation, or the wheel hitting the arch when turning. However, many car owners face a problem: where exactly on the disk is the offset indicated?, if the markings are erased or missing?

In this article we will analyze all possible locations of the markings ET on cast, stamped and forged wheels, we will learn to decipher the designations (for example, ET45 or ET-15), and we will also show you how to measure the offset yourself using available tools. Let us separately dwell on the consequences of incorrectly selecting the offset - from vibrations on the steering wheel to breakdown of suspension elements.

Where to look for the offset (ET) marking on a wheel

Manufacturers place offset markings on the disc in several standard places, but their location depends on the type of disc (stamped, cast, forged) and brand. Here the most common options:

  • 🔍 On the inside of the disk (from the side of the mating plane to the hub) - the most common place. Look for an engraving or sticker with parameters like 6.5Jx16 ET45.
  • 📏 On the rim between the spokes (relevant for alloy wheels BBS, OZ Racing, Enkei). Markings can be embossed or lasered.
  • 🖼️ On the certification sticker (often on the back of stamped discs, e.g. Kosei or Steel Wheels). The sticker may contain complete options including ET, PCD and DIA.
  • 🔧 At the center hole (DIA) - less often, but some brands (for example, Ronal) duplicate the main parameters there.

If the disc is used or the markings have been erased, pay attention to additional designations:

  • 🔄 OFFSET - English equivalent ET (for example, OFFSET +45).
  • ⚖️ DEPORT - French departure designation (found on disks Peugeot/Citroen).
📊 Where do you usually look for offset markings on a disc?
On the inside
Between the spokes
On a sticker
I don't know where to look

Important! On Chinese discs without a brand (for example, Replica or NoName) markings may be applied with paint, which will wear off over time. In this case, you will have to measure the offset yourself (more on this in the next section).

How to decipher the departure designation: ET45, ET0, ET-15

Departure markings always contain letters ET (less often - OFFSET) and a number, which can be:

  • 📈 Positive (for example, ET45) — the mating plane is shifted inside disk relative to the central axis.
  • 📉 Negative (for example, ET-15) - the plane is taken out outward, the disk “sticks out” from the arch.
  • ➖ Zero (ET0) - the mating plane coincides with the central axis of the disk.

Let's look at examples:

Marking What does it mean Typical Application
ET45 Overhang +45 mm (the disk is “recessed” inside) Standard for most sedans (Toyota Camry, Honda Accord)
ET20 Overhang +20 mm (moderately “convex” disk) Crossovers (Nissan Qashqai, Hyundai Tucson)
ET-10 Overhang -10 mm (disc protrudes strongly outward) Tuned cars, wide wheels on BMW M or Audi RS
ET0 Zero departure Sports cars (Porsche 911, Nissan GT-R)

Critical error: if the disk shows a crash ET38, and the car manufacturer provides ET45, a difference of 7mm will result in the wheel moving outward by 3.5mm on each side. This increases the load on the wheel bearing by 20–30% and reduces its life by 2–3 times.

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If the disc specifies a range (for example, ET35-45), this means that the disc is universal and suitable for several car models. But you can ONLY use it if your original ET falls within this range!

How to measure disc offset (ET) without markings: step-by-step instructions

If the markings are worn out or missing, you can measure the offset yourself using ruler, caliper and straight edge. You will need:

  1. Remove the wheel from the car and clean the mounting surface from dirt.
  2. Place the disc on a flat surface face down (matting plane up).
  3. Measure the width of the disk (W) - the distance between the inner edges of the rim (for example, 7 inches = 177.8 mm).
  4. Lay a flat strip (for example, a metal corner) across the rim and measure the distance from the mating plane to the bottom edge of the strip (X).
  5. Calculate departure using the formula: 
    ET = X - (W / 2)

    where W — disk width in mm, X — measured distance.

Calculation example:

  • Disc width (W) = 8 inches = 203.2 mm.
  • Measured distance (X) = 120 mm.
  • Departure (ET) = 120 - (203.2 / 2) = 120 - 101.6 = +18.4 mm (round up to ET18).

Caliper or ruler with depth gauge|Level rod (metal corner)|Calculator for calculations|Clean rag for cleaning the disc-->

⚠️ Attention: If the disc has a complex geometry (for example, with deep “pockets” between the spokes), measure X needed from the mating plane to imaginary rim plane, and not to the actual edge. To do this, use a rail at least 30 cm long.

Consequences of incorrect disc ejection: from vibrations to suspension failure

An error in offset of even 5–10 mm can lead to serious problems. Here the most common consequences:

  • 🔥 Accelerated wear of wheel bearings — the displacement of the center of mass of the wheel increases the load on the bearing by 1.5–2 times. Symptoms: noise when driving, wheel play.
  • 🚗 Incorrect steering operation — the car “steers” to the side, the steering wheel becomes tight or, conversely, too light.
  • 💥 Wheels hitting arches or suspension elements - especially when fully loaded or on uneven surfaces. Often found when installing disks with ET less than original.
  • ⚡ Vibrations on the steering wheel and body - arise due to imbalance and uneven distribution of wheel weight.

The table below shows the relationship between departure deviation and risks:

Deviation of ET from the original Consequences Duration of manifestation of problems
±3 mm Minimal: barely noticeable vibration possible at high speeds After 10–15 thousand km
±5–10 mm Medium: accelerated bearing wear, uneven tire wear After 5–10 thousand km
±15 mm or more Critical: impacts, destruction of suspension, loss of controllability Immediately or after 1–2 thousand km

⚠️ Attention: On vehicles with multi-link suspension (for example, Audi A4, BMW 3 Series) even a deviation of 5 mm can lead to breakage of levers or silent blocks due to changes in suspension angles. On machines with spring suspension (for example, VAZ 2110, Renault Logan) a deviation of up to 10 mm is permissible, but no more.

How to choose a disc with the correct offset: 3 proven methods

To avoid mistakes when selecting drives, use one of these methods:

  1. Original manufacturer parameters

    Find data for your model in instruction manual or on the official website of the brand. For example, for Volkswagen Golf VII original departure - ET45–50 (depending on the engine).

  2. Disc directories

    Use services like Diski.ru, AlloyWheelsDirect or TireRack, where you can select wheels by car brand. Pay attention to the filter by ET!

  3. Measuring a stock disk

    If you already have wheels that meet all the parameters, measure their offset (as described above) and look for similar ones.

⚠️ Attention: On some vehicles (for example, Mercedes-Benz or Porsche) offset may differ for the front and rear axles! Always check this in your documentation.

What to do if the required ET is not on sale?

If you cannot find a disk with the original offset, you can use spacers (aluminum or steel rings that compensate for the difference). However, remember:

- Spacers increase effective offset (for example, a 10 mm spacer on the disc ET35 will give ET45).

- Spacers thicker than 15 mm cannot be used without modifying the hub (extended bolts, alignment).

- On cars with ABS, spacers can disrupt the operation of speed sensors!

Frequently asked questions about disc ejection (ET)

Let's look at the most popular misconceptions and questions that car owners have.

Is it possible to install wheels with an offset smaller than the original (for example, ET30 instead of ET45)?

Technically it is possible, but this will lead to the wheel protruding outward, increasing the track. Consequences:

  • Risk of the wheel hitting the arch when turning or on uneven surfaces.
  • Increased load on the wheel bearing and steering rods.
  • Failure to pass technical inspection (in some countries this is considered a design change).

The permissible reduction in overhang is no more than 5 mm from the original (for example, ET40 instead of ET45).

What happens if you install wheels with an offset larger than the original ones (for example, ET50 instead of ET35)?

The wheel will “sink” inside the arch, which will lead to:

  • Shifting the center of mass of the wheel closer to the suspension - increasing the load on the shock absorbers.
  • Possible contact with elements of the brake system (for example, calipers).
  • Deterioration in handling (the car will become less responsive to the steering wheel).

The permissible increase in overhang is up to 10 mm from the original.

How does offset relate to rim width?

Disc width (J) and departure (ET) are interrelated parameters. For example, if you install a wider drive (eg. 8J instead of 7J), then to maintain the original wheel fit, the offset must be less by 10–15 mm. It's called adjustment of offset to width.

Formula for approximate calculation: 

New ET = Original ET - ((New width - Original width) / 2)
Is it possible to determine the offset by the VIN code of the car?

No, the VIN contains information about the model, engine and major options, but not about disk parameters. However, you can find out by VIN accessory code car, and then find the original disk parameters in spare parts catalogs (for example, ETKA for Volkswagen Group or EPC for Mercedes).

Does offset affect tire wear?

Yes, and very significantly! Incorrect departure leads to:

  • Uneven tread wear (for example, sawtooth wear on the inside or outside).
  • Increased load on the side walls of the tire, which reduces its service life by 20–30%.
  • Risk of cord detachment when driving over uneven surfaces (due to improper distribution of forces).
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Even if the disc physically fits onto the hub and does not catch the arch, this does NOT guarantee correct alignment. The consequences of incorrect ET appear gradually: from vibrations to suspension failure.