Have you ever heard a car mechanic say: “These wheels won’t fit - they have the wrong offset”? Or did you notice how, after replacing the wheels, the car began to “walk” along the road, and the steering wheel began to vibrate at speed? All this may be related to incorrect disc offset - a parameter that many car owners ignore when buying new wheels. Meanwhile, incorrect departure (ET) not only spoils the appearance of the car, but also accelerates suspension wear by 2–3 times, and in critical cases can lead to an accident.

In this article we will look at:

  • 🔧 What is it disc offset ET and how it is measured (with formulas and examples).
  • ⚠️ Why you can’t install wheels with the “wrong” offset - consequences for suspension, steering and safety.
  • 📏 How to independently measure the offset on an installed disk (step-by-step instructions with photos).
  • 🔄 Is it possible to drive with a non-standard departure and when is this permissible?
  • 🛒 Where to find the correct offset for your car model (manufacturer tables and online services).

If you are planning to buy new drives or have already encountered problems after installing them, this article will help you avoid costly mistakes.

1. What is ET - Simple Explanation

Disc offset (ET, from German EinpressTiefe) is the distance between disk mating plane (the part that presses against the hub) and imaginary central axis of the disk. It is measured in millimeters and can be:

  • 🔹 Positive (ET > 0) — the mating plane protrudes outward relative to the center.
  • 🔹 Zero (ET = 0) - the plane coincides with the axis.
  • 🔹 Negative (ET < 0) — the plane is recessed inward.

For example, if the disk says ET45, this means that the offset is 45 mm towards the outside of the wheel. Most production cars have a positive offset (from ET30 up to ET50), but tuned cars or SUVs often have wheels with a negative offset to widen the track.

It is important to understand: offset is not the width of the rim or its diameter. This is a separate geometric parameter that determines how the wheel will “sit” relative to the arch and suspension. Even if the disc diameter and bolt pattern are correct, incorrect ET may make it unsuitable for your car.

📊 What wheel offset is on your car?
Standard (according to the manual)
Slightly modified (within ±5 mm)
Heavily modified (tuning)
I don't know

2. Why disc offset is so important: consequences of incorrect ET

Many car owners mistakenly believe that if the disc physically “fits” under the arch and does not hit the suspension, then it can be installed. In fact even a minimal deviation of the offset from the standard value leads to serious problems:

⚠️ Attention! Installation of disks with an offset differing from the factory one by more than ±5 mm, is considered unsafe and can lead to:
  • 🔧 Accelerated wear of wheel bearings (the load is distributed unevenly).
  • 🚗 Deterioration in controllability: the car “scours” along the road, the steering wheel becomes “tight” or, conversely, too sensitive.
  • 💥 Increased load on shock absorbers and suspension arms (the risk of their breakdown increases by 30–40%).
  • 🔄 Incorrect operation of ABS and ESP (sensors read distorted data on wheel position).

Case study: on Volkswagen Golf IV standard offset of front discs - ET38. If you install disks with ET20 (difference of 18 mm), then:

  • The wheel will move outward by 9 mm on each side (since changing ET affects the position symmetrically).
  • The track will increase by 18 mm, which will lead to increased wear of ball joints and silent blocks.
  • When turning sharply, the tire may touch the fender liner or shock absorber.

The opposite situation (for example, ET50 instead of ET38) will move the wheel inside, which is fraught with:

  • 🔹 Contact of the disc with the brake caliper (especially on cars with large brakes).
  • 🔹 Reduced stability at high speeds (the center of gravity shifts).
💡

If you buy used wheels, be sure to check the offset using a caliper or ruler. Sellers often indicate incorrect parameters, especially if the wheels are tuned.

3. How to measure the disc offset yourself (step-by-step instructions)

If you don't trust the markings on the disc or they have worn off, you can measure the offset manually. You will need:

  • 📏 Ruler or caliper (more precisely).
  • 📐 Square or even strip.
  • 🔨 Chalk or marker.

Measurement algorithm:

  1. Remove the disc from the car and place it on a flat surface face up.
  2. Attach the rack to the rim of the disc (where the rubber is attached) and measure the distance to the mating plane (value A).
  3. Turn the disk over and repeat the measurement on the other side (B value).
  4. Measure the width of the rim (C value) is the distance between the inner edges of the rim.

Now use the formula:

ET = (A + B - C) / 2 - B

Calculation example:

  • A = 120 mm (distance from the rim to the mating plane on the front side),
  • B = 100 mm (same from the back side)
  • C = 200 mm (disc width).

Substitute into the formula:

ET = (120 + 100 - 200) / 2 - 100 = (20) / 2 - 100 = 10 - 100 = -45 mm

Thus, the offset of this disk is ET-45.

Ensure that the offset (ET) is the same as factory (±2 mm)|Check the bolt pattern (PCD) and hub diameter (DIA)|Check the wheel width and diameter as recommended|Inspect the wheel for cracks or deformation-->

4. Is it possible to drive with a non-standard reach?

Technically yes, but only within strictly limited limits. Here's what the experts say:

Deviation from standard departure Consequences Is it permissible?
±2 mm Invisible to the driver, suspension wear is minimal ✅ Yes
±5 mm Slight change in handling, increased bearing wear ⚠️ Highly undesirable, but possible
±10 mm or more Heavy load on the suspension, deterioration of directional stability, risk of wheel contact with the arch ❌ No
Negative ET (if stock positive) Widening of the track, possible contact with the suspension when turning the steering wheel ❌ Only for tuned cars with modified suspension

Exceptions:

  • 🔧 Tuned cars with reinforced suspension (for example, BMW M3 or Subaru WRX STI) sometimes they use wheels with a modified offset to improve handling. But it requires recalculation of suspension geometry and installation of special components.
  • 🏎️ Racers track cars may experiment with ET to optimize weight distribution. But this is unacceptable on road cars.
⚠️ Attention! If you decide to install wheels with a non-standard offset, be sure to:
  • 🔹 Swipe wheel alignment after installation.
  • 🔹Reduce tire pressure by 0.2–0.3 bar to compensate for the changed load.
  • 🔹 Check the condition of wheel bearings and silent blocks regularly (every 5,000 km).

5. Where to find the correct offset for your car

The most reliable source - car operating instructions or a sticker on the door pillar (where the recommended wheel sizes are indicated). If there is no documentation, use one of the following methods:

  • 📄 Official catalogs of disk manufacturers:

    These sites have a search by car model indicating all valid parameters, including ET.

  • 🔍 Online databases:
    • 🔹 Wheel-Size.com — a catalog with wheel sizes for 90% of cars.
    • 🔹 TireRack.com — American database with filters by year of manufacture.
  • 📱 Mobile applications:
    • 🔹 WheelFitment (Android/iOS) - allows you to select wheels by VIN code.
    • 🔹 Tire & Wheel Calculator — calculates permissible deviations ET.

Search example for 2018 Toyota Camry:

  1. Let's go to Wheel-Size.com.
  2. Select the make, model and year.
  3. In the section Wheel Specifications look at the line Offset (ET) - for Camry this is usually ET45.
What to do if your model is not in the database?

If your car is rare or new, try:

1. Find a forum for owners of this model (for example, on Drive2.ru or Club-Toyota.ru).

2. Ask an authorized dealer - they have technical bulletins with exact parameters.

3. Measure the offset on standard wheels (if they are original).

6. Frequent myths about disc failure

There are many misconceptions surrounding the topic of ET. Let's look at the most common ones:

  • 🚫 Myth 1: “If the disc fits on the hub and does not hit the arch, then the offset is correct”

    ❌ Reality: Even if the disk physically fits, incorrect ET changes the load vectors on the suspension. For example, on Honda Civic disks with ET35 instead of ET45 may not rub, but at the same time 20% increase wear on shock absorbers.

  • 🚫 Myth 2: “Negative offset is only for tuning”

    ❌ Reality: Some production SUVs (for example, Jeep Wrangler or Toyota Land Cruiser 200) have negative ET from the factory for increased off-road stability.

  • 🚫 Myth 3: “You can compensate for incorrect offset with spacers”

    ❌ Reality: Spacers are only changed disc position relative to the hub, but do not correct the load distribution. For example, if you installed a disk with ET20 instead of ET40 and added a spacer 20 mm, then:

    • 🔹 The wheel will still be shifted outward relative to the standard position.
    • 🔹 The load on the wheel bearing will increase.
💡

The only safe way to change the offset is to use wheels certified by the car manufacturer for your model. Even if they are more expensive than “universal” ones, they are cheaper than suspension repairs.

7. FAQ: Answers to frequently asked questions about disc failure

❓ Is it possible to install wheels with ET0 offset on a car with a standard ET45?

❌ No, it's critical deviation (difference 45 mm). These discs:

  • Move the wheel outward by 22.5 mm on each side.
  • Will cause strong vibration of the steering wheel at speeds above 80 km/h.
  • Will lead to wheel bearing failure within 10–15 thousand km.

The exception is if you simultaneously install widened arches and reinforced suspension (like on rally cars).

❓ How does departure affect fuel consumption?

🔹 Extended offset (ET higher than standard) moves the wheel inward, which reduces the rolling shoulder and reduces rolling resistance. Theoretically, this could reduce consumption by 0.1–0.3 l/100 km, but in practice the effect is invisible.

🔹 Reduced offset (ET below standard) widens the track and increases the load on the suspension, which increases consumption on 0.3–0.7 l/100 km (due to increased resistance).

❓ What is “zero offset” and what cars is it suitable for?

ET0 means that the mating plane of the disk coincides with its central axis. Such disks are often used:

  • 🔹 On sports cars (for example, Porsche 911 or Nissan GT-R) for optimal weight distribution.
  • 🔹 On SUVs to increase the track width (for example, Mercedes G-Class).
  • 🔹B drifting, where maximum rear wheel grip is important.

For regular sedans or hatchbacks ET0 does not fit - it will lead to excessive load on the suspension.

❓ Is it possible to change the wheel offset without buying new wheels?

🔹 Spacers - a temporary solution, but they:

  • Load distribution is not corrected.
  • May call steering wheel beating, if unbalanced.

🔹 Disc regrinding — some workshops offer to “remill” the mating plane, but this:

  • Weakens the disc structure (risk of cracks).
  • Void the warranty (if the disk is new).

🔹 The only right way — buy wheels with suitable ET.

❓ Why can there be different departures in the front and rear on one car?

This is typical for:

  • 🔹 Rear wheel drive cars (for example, BMW 5 Series), where the rear axle is wider than the front for better stability.
  • 🔹 Sports cars with independent multi-link suspension (for example, Audi RS3).
  • 🔹 SUVs with different wheelbase widths (for example, Land Rover Defender).

In such cases The offset of the rear discs is usually less (for example, ET35 front and ET20 rear) to compensate for the shift in center of gravity.