ET 35 on disks: what is it and why is it important to know this parameter

Have you ever noticed the inscription ET 35 on car rims? This mysterious code is found on most wheel products, but not all drivers understand its meaning. Meanwhile, ET (or offset) is one of the key parameters that directly affects the safety, handling and even the appearance of your car.

If you are planning to buy new wheels, change tires, or just want to understand the technical characteristics of your car, this article is for you. We will not only decipher what it is ET 35, but we will also explain how this parameter is related to suspension geometry, why you cannot ignore the manufacturer’s recommendations, and what will happen if you install wheels with an inappropriate offset. Spoiler: the consequences can be much more serious than just “looks ugly.”

What is ET on disks and how is it measured?

ET (from German EinpressTiefe) is the disc offset, that is, the distance between the mating plane (the place where the disc is attached to the hub) and the imaginary central axis of the disc. It is measured in millimeters and can be:

• 🔹 Positive (ET 35, ET 40) - the mating plane is shifted outward relative to the center;
• 🔹 Zero (ET 0) - the plane coincides with the central axis;
• 🔹 Negative (ET -10, ET -20) - the plane is shifted inward.

For example, ET 35 means that the mating plane is spaced from the center of the disk by 35 mm towards the outside of the wheel. This parameter is important because it determines how the disc will "sit" on the hub and how the wheel will interact with the arch, suspension and steering.

Car manufacturers carefully calculate the permissible offset for each model, taking into account:

• 📏 Suspension geometry;
• 🚗 Wheel load;
• 🔧 Steering features;
• 💨 Aerodynamics and heat dissipation from the brakes.

Why ET 35 is one of the most common departures

If you look at the wheels for most production cars (especially European and Japanese brands), you will notice that ET 35 occurs more often than other meanings. Why?

The fact is that this departure is considered universal for middle class passenger cars. It provides:

• 🔧 Optimal load distribution on the hub bearings;
• 🚗 Stable handling without excessive load on the steering;
• 🛡️ Sufficient clearance between the wheel and suspension elements/brake system;
• 🎨 Visual harmony - the wheels do not look too “recessed” or excessively protruding.

For example, ET 35 often found on models such as:

• 🚘 Volkswagen Golf, Passat, Polo;
• 🚘 Skoda Octavia, Fabia;
• 🚘 Toyota Corolla, RAV4;
• 🚘 Hyundai Tucson, Kia Ceed.

However, this does not mean that ET 35 fits any car. For example, compact hatchbacks may require ET 40-45, and for SUVs - ET 20-30 or even negative departure.

What happens if you install disks with the wrong ET

Many drivers mistakenly believe that offset is a “trifle” and that if the disc physically fits onto the hub, then it can be used. In practice it is not suitable ET leads to serious problems:

Problem	ET is too high (eg ET 50 instead of ET 35)	ET is too small (eg ET 20 instead of ET 35)
🔧 Suspension load	Increased load on the internal bearings of the hub, accelerated wear	The load is shifted to external elements, risk of deformation of the levers
🚗 Manageability	The steering wheel becomes “stiff”, the car reacts worse when turning	The steering wheel is too light, the car “throws” along the road, especially at high speed
🛡️ Security	Risk of the wheel hitting the arch when fully loaded or on uneven surfaces	The wheel may touch the brake caliper or suspension components
🔥 Tire wear	Uneven wear on the inside of the tread	Uneven wear on the outer tread

It is especially dangerous to install disks with ET, which is very different from the factory one. For example, if in a car with the recommended ET 35 install disks with ET 20, then:

• 🔴 The wheels will protrude beyond the arches, which is prohibited by traffic rules (fine up to 500 rubles under Article 12.5 of the Administrative Code);
• 🔴 The rolling shoulder will increase, which will lead to increased load on the steering rack;
• 🔴 The risk of aquaplaning will increase due to changes in the wheel angle.

What is a rolling shoulder?

The rolling shoulder is the distance between the point of contact of the wheel with the road and the steering axis of the wheel. The greater the deviation of ET from the norm, the more the rolling shoulder changes, which directly affects controllability and wear of parts.

⚠️ Attention: If you are installing wheels with a non-standard offset, be sure to check them for disk drive (stand for checking geometry). Even a small deviation of 5-10 mm can lead to vibrations at high speed.

How to find out the correct ET for your car

In order not to make a mistake when choosing disks, you need to know recommended departure for your car model. There are several ways to find out:

1. Instructions for use — technical specifications always indicate acceptable disk parameters, including ET.
2. Sticker on the door pillar - Many cars have a sign with recommended wheel sizes and offset.
3. Manufacturer's official website — in the “Technical Specifications” or “Accessories” section.
4. Disk databases - for example, Diski.ru, Kolesa.ru or Alloy Wheels Direct.
5. Consultation at a car service center — craftsmen can measure the offset using special equipment.

Example: for Volkswagen Golf VII with the 1.4 TSI engine the factory offset is ET 38-45 (depending on the width of the disk). This means that ET 35 will be close to acceptable, but still not ideal. In such cases, it is better to choose disks with ET 38to avoid problems.

If you are not sure whether it will fit ET 35 for your car, use disc offset calculator (available on many car portals). It will help you calculate how much the load on the suspension will change when installing wheels with a different offset.

Is it possible to install wheels with ET 35 if the manufacturer recommends a different offset?

This question often arises among drivers who want to install wheels with ET 35, although the instructions indicate, for example, ET 40. Let's figure out how critical a deviation of 5 mm is.

According to experts, permissible offset deviation is ±5 mm from the factory value. That is:

• 🔹 If recommended ET 40, then ET 35-45 will be acceptable;
• 🔹 If recommended ET 30, then ET 25-35 will do;
• 🔹 If recommended ET 20, then ET 35 it will already be risky choice.

However, even within the acceptable deviation, nuances may arise:

• 🔴 On cars with independent multi-link suspension (for example, Audi A4, BMW 3-series) even a small change in reach has a greater effect on controllability;
• 🔴 On front-wheel drive auto (for example, VAZ 2110, Renault Logan) negative offset increases the load on the CV joints;
• 🔴 On SUVs (for example, Toyota Land Cruiser, Nissan Patrol) too much overhang can lead to wheels touching the fender liners when fully loaded.

⚠️ Attention: If you are installing wheels with an offset different from the factory one, be sure to wheel alignment after replacement. Even a small change in ET affects wheel alignment!

How to measure disc offset (ET) yourself

If you are buying used wheels or want to check the compliance with the declared ET In fact, you can measure the offset yourself. For this you will need:

• 📏 Ruler or caliper;
• 📐 Square;
• 📝 A sheet of paper and a pencil;
• 🔨 Smooth surface (for example, a table).

Measurement algorithm:

1. Place the disc on a flat surface face down.
2. Attach the square to the rim of the disk and measure the distance from the mating plane to the edge of the rim (denoted as A).
3. Turn the disc over and measure the distance from the mating plane to the opposite edge of the rim (denoted as B).
4. Measure the width of the rim (C).
5. Calculate the offset using the formula:

   ET = (A + B - C) / 2

Example: if A = 110 mm, B = 180 mm, and the width of the disk C = 200 mm, then:

ET = (110 + 180 - 200) / 2 = 45 mm

That is, the departure of such a disk is ET 45.

Please note: this method is an approximate result. For accurate measurements use laser meter or contact a tire shop.

ET 35 and tuning: what you need to know before installing wide rims

Many car owners want to give their car a more aggressive look by installing wide wheels with a smaller offset (for example, ET 20 instead of ET 35). However, such tuning requires caution.

This is what happens when you reduce ET:

• 🔹 The wheels move outward, which visually expands the wheelbase;
• 🔹 The track increases, which can improve stability on straight sections;
• 🔹 But! The load on the wheel bearings and steering rack increases;
• 🔹 Controllability at low speeds worsens (the steering wheel becomes “heavier”).

If you still decide to install disks with ET 35 instead of the factory one ET 45, consider the following nuances:

• 🔧 You may have to use spacers (spasers) to adjust the departure;
• 🚗 Will be required rolling out arches or installation expandersso that the wheels do not rub against the body;
• 🛡️ Be sure to check if the wheel is touching brake caliper or shock absorber;
• 📜 Make changes to STS, if the new wheels exceed the dimensions of the car (otherwise a fine).

Case study: on BMW E46 factory rear disc offset - ET 15-20. If you install ET 35, the wheels will “sink” inside the arches, which will worsen the appearance and may lead to contact with the suspension.

FAQ: Frequently asked questions about ET 35

❓ Is it possible to install wheels with ET 35 on a car if the factory offset is ET 40?

Yes, if the difference does not exceed ±5 mm. However, please note that ET 35 will move the wheel outward by 5 mm, which can lead to:

• 🔹 Slight increase in load on the wheel bearing;
• 🔹 Possible wheel hitting the arch when fully loaded;
• 🔹 A slight change in handling (the steering wheel will become a little lighter).

It is recommended to check the clearances on the lift or pit.

❓ Which ET is better for winter wheels: 35 or 40?

For winter wheels it is better to stick to factory departure. If the manufacturer recommends ET 40, then winter wheels should be with ET 40. The point is that:

• 🔹 Winter tires are usually wider, and moving the wheel outward (ET 35) can lead to touching;
• 🔹 On a slippery road, even a slight change in departure affects directional stability;
• 🔹 At negative temperatures, the suspension works harder, and the additional load from non-standard ET will accelerate wear.

❓ What does the inscription ET 35 on the disk mean if other numbers are also indicated there, for example, 7Jx16?

The disk usually contains several parameters:

• 🔹 7J - rim width in inches (7 inches) and flange shape (J - for single-wheel drive cars);
• 🔹 x16 — bore diameter in inches (16");
• 🔹 ET 35 — offset in millimeters;
• 🔹 PCD 5x112 — bolt pattern (5 holes, circle diameter 112 mm);
• 🔹 DIA 57.1 - diameter of the central hole.

All these parameters must match the recommendations of the car manufacturer.

❓ Is it possible to drive with different ET on the front and rear wheels?

No, this is highly not recommended. Different offsets on the axles lead to:

• 🔴 Unpredictable controllability (the car can “steer” to the side);
• 🔴 Uneven tire wear;
• 🔴 Increased load on the differential (for all-wheel drive cars);
• 🔴 Risk of skidding when braking.

The exception is some sports cars, where different ET is used to adjust the balance, but this requires professional suspension tuning.

❓ What is the penalty for discs with incorrect ET?

According to Art. 12.5 of the Code of Administrative Offenses of the Russian Federation, if the rims exceed the dimensions of the car (which often happens when the ET is too small), the inspector can issue a fine:

• 🔹 500 rubles - for the first violation;
• 🔹 Up to 5,000 rubles — if the wheels touch elements of the body or suspension;
• 🔹 Prohibition on exploitation - until the problem is eliminated.

In addition, in the event of an accident, the insurance company may recognize discs with non-standard ET non-standard equipment and refuse payment.