Wheel spacers: purpose, types and installation rules

Wheel spacers are parts that are installed between the car hub and the wheel rim, increasing disc ejection (ET). At first glance, it may seem that this is just a “cosmetic” modification for those who like wide wheels or an aggressive appearance. However, in practice, spacers solve much more serious problems: from adjusting suspension geometry to preventing tire friction on arches during tuning.

In this article we will figure out What are wheel spacers really for?what types are there (including universal, hub and adapters), and also reveal critical errors that lead to vibrations, backlash and even accidents after incorrect installation. If you are planning to install spacers on your car, be sure to read to the section with the compatibility table and FAQ.

Why do they put spacers on wheels: 5 real reasons

Many car owners believe that spacers are needed solely for “beauty” - to make the wheels look wider and the car seem more “angry”. In fact, this is only one of the reasons, and far from the most important. Here five practice problems, which are solved by wheel spacers:

• 🔧 Wheel offset adjustment (ET). If, after replacing the disks, the wheels “sink” inside the arch or, conversely, stick out, spacers help restore the optimal geometry. This is especially true when switching to wheels with a different offset (for example, with ET45 on ET35).
• 🚗 Eliminating tire friction on fender liners. When installing wider tires or lowering the suspension, the wheels may touch the arches. Spacers move the wheel outward, preventing contact.
• ⚙️ Brake Compatibility. Sports and tuned cars often have multi-piston calipers that do not fit under standard discs. Spacers increase the clearance.
• 🔄 Unification of disks on different axes. For example, if the front axle has discs with ET20, and on the back - with ET40, spacers help level the offset for a symmetrical look.
• 💨 Improved aerodynamics. On racing cars, spacers are used to optimize air flow around the wheels, reducing drag.

However, not everything is so simple: incorrectly selected spacers can accelerate wear of wheel bearings, cause vibrations at speed or even cause the wheel to come off. Therefore, before installation, be sure to read the section about risks and mistakes.

Types of wheel spacers: what they are and how they differ

All spacers are divided into three main types, each of which solves its own problems. The choice depends on car design, installation purposes and budget. Let's take a closer look at them.

1. Universal (flat) spacers

The simplest and most budget option is metal or aluminum rings with a thickness of 3 mm up to 25 mm. They are installed between the hub and the disc, increasing the offset. Suitable for most passenger cars, but have limitations:

• ✅ Cheap and easy to install.
• ❌ Not suitable for cars with central nut (for example, BMW or Mercedes).
• ❌ May cause vibrations if not balanced.

2. Hub spacers (hubs)

A more complex design that replaces or extends the standard hub. Such spacers are often used on SUVs and pickup trucks, where it is necessary to significantly increase the reach (up to 50 mm and more). Benefits:

• ✅ Withstand high loads.
• ✅ Suitable for heavy vehicles.
• ❌ Requires precise fitting to the model.
• ❌ 2-3 times more expensive than universal ones.

3. Adapters (spacers with fastening)

These are spacers that not only increase the offset, but also change the bolt pattern (PCD). For example, they allow you to install disks from Volkswagen on Toyota. Often used for tuning or restoration after an accident. Important: adapters must be certified and match ISO 9001, otherwise the risk of the wheel coming off increases significantly.

Which type should I choose? Answer two questions:

1. Do I need to change the bolt pattern?PCD)?
2. How much does the reach need to be increased?

If the answer to the first question is “no”, and the departure needs to be changed to 10–20 mm — enough universal spacers. If a change is required PCD or departure more 25 mm — you will have to fork out for adapters or hubs.

What is PCD and how to measure it?

PCD (Pitch Circle Diameter) is the diameter of the circle on which the bolt holes are located on the disc. Measured in millimeters (eg PCD 5×112 means 5 holes on a circle with a diameter of 112 mm). To measure PCD yourself:

1. Take a caliper.

2. Measure the distance between the centers of two adjacent holes.

3. Multiply by the coefficient (for 4 bolts - 1.414, for 5 - 1.701, for 6 - 2).

The result is your PCD.

Spacer thickness: how to choose and not make a mistake

The main parameter when choosing is spacer thickness. It determines how much the wheel will move relative to the arch. But there are pitfalls here:

• 🔴 Too thin (up to 5 mm) spacers have almost no effect, but can cause imbalance.
• 🟡 Average (10–20 mm) is the best option for most passenger cars.
• 🟢 Fat (from 25 mm) require lengthening of the bolts and may affect the performance of the suspension.

How to calculate the required thickness? Use the formula:

Spacer Thickness (mm) = (Desired ET - Current ET) × (-1)

Example: if you have a disk with ET40, but it is necessary ET20, then:

(20 - 40) × (-1) = 20 mm

You will need a spacer thick 20 mm.

But be careful: if the spacer is thicker 25 mm, you will need:

Dangers and errors: what will happen if spacers are installed incorrectly

Spacers are not a harmless accessory. Incorrect installation or selection can lead to serious consequences, including accidents. Here are the most common mistakes and their consequences:

⚠️ Attention! If the spacer is not centered on the hub (for example, it only has bolt holes but no center ring), the wheel will “kick” at speeds above 80 km/h. This leads to accelerated wear of bearings and ball joints.

Error	Consequences	How to avoid
Using cheap aluminum spacers	Heat deformation, wheel play	Choose spacers made of steel or titanium
PCD mismatch	The wheel does not fit tightly, vibrations	Check the bolt pattern before purchasing
Lack of balancing after installation	Steering wheel wobble at speed	Be sure to balance the wheel
Using standard bolts with thick spacers	Insufficient fixation, risk of wheel coming off	Extend bolts or use studs

One more critical error - ignoring changes in suspension load. Spacers move the wheel's center of gravity outward, which increases leverage. As a result:

• Wear accelerates wheel bearings (1.5–2 times).
• The load on shock absorbers and springs.
• May change wheel alignmentwhich will lead to uneven tire wear.

If you are not confident in your skills, trust the installation of spacers to professionals. The service will check:

• 🔹 Compatible with the brake system.
• 🔹 No contact between the tire and the arch when fully loaded.
• 🔹 Correct tightening of bolts (tightening torque must comply with factory recommendations).

Spacers and the law: what the traffic police says

From a legal point of view, spacers refer to vehicle design changes. According to Technical Regulations of the Customs Union 018/2011, any modifications affecting safety must be certified and included in the PTS.

In practice:

• ✅ Spacers up to thickness 15 mm usually do not raise questions from inspectors.
• ⚠️ Spacers are thicker 20 mm may result in a fine (500–800 rub.) or requirements to pass technical expertise.
• ❌ If spacers led to wheels extending beyond body dimensions, this is considered a violation (clause 7.9 of the traffic rules) and is punishable by a fine 500 rub. or a ban on exploitation.

To avoid problems:

1. Save receipts and certificates for spacers.
2. If the thickness of the spacers is more than 20 mm, get a conclusion preliminary technical examination.
3. Check that the wheels do not extend beyond the dimensions of the vehicle (measured at the outermost point of the tire).

⚠️ Attention! On vehicles with electronic driver assistance systems (for example, Lane Assist or Adaptive Cruise Control) spacers can interfere with the calibration of sensors. This will lead to false alarms or failure of the systems.

How to install spacers yourself: step-by-step instructions

If you decide to install spacers yourself, follow this algorithm. You will need:

• 🔧 Jack and stops.
• 🔩 Torque wrench (required!).
• 🔨 Socket heads and extension.
• 🧲 Magnet for bolts (so as not to lose).

Step 1. Preparation

Park the car on a level surface, tighten the handbrake and place chocks under the wheels. Remove the hubcap (if equipped) and loosen the bolts on the wheel without removing it completely.

Step 2. Wheel removal

Raise the car with a jack, remove the wheel and clean the hub from dirt. Check if there is any on the hub beads or burrswhich may prevent the spacer from sealing tightly.

Step 3. Installing the spacer

Place the spacer onto the hub, lining up the bolt holes. Make sure she sits down tight and without distortion. If the spacer has a central ring, it should be perfectly centered on the hub.

Step 4: Attaching the Wheel

Install the wheel on the spacer and tighten the bolts. Tighten them up criss-cross in 2-3 approaches using a torque wrench. Check the tightening torque in your car's manual (usually 90–120 Nm).

Step 5. Check

Lower the vehicle and finally tighten the bolts. Ride at low speed (20–30 km/h) and check:

• No vibrations on the steering wheel.
• Are there any extraneous sounds (creaks, knocks).
• The wheel does not rub against the arch when turning.

1. Correct alignment of the spacer.

2. Wheel balancing.

3. Tightening the bolts.

Vibration at speeds above 60 km/h can lead to destruction of the wheel bearing!-->

FAQ: Frequently asked questions about wheel spacers

Is it possible to install spacers of different thicknesses on the front and rear axles?

Technically possible, but it will change car behavior on the road. Different thickness of spacers front and rear shifts axis of symmetry, which can lead to:

• Deterioration of directional stability (the car will “yaw”).
• Uneven tire wear.
• Changing the turning radius.

If the difference does not exceed 10 mm, this is acceptable. If there are more, it is better to choose the same spacers or consult a suspension specialist.

Do spacers affect fuel consumption?

Yes, but only slightly. Spacers increase roll-in shoulder (distance from the center of the wheel to the steering axis), which slightly increases the load on the suspension and rolling resistance. As a result, fuel consumption may increase by 1–3% (depending on the thickness of the spacers and driving style).

Have a more noticeable impact wide tires, which are often installed together with spacers - they increase air resistance.

Is it possible to drive in winter with spacers?

Yes, but with reservations:

• ✅ Spacers do not affect road grip directly.
• ⚠️ In winter, the load on the suspension increases due to spacers (snow, ice, tires), therefore:
• Check the condition wheel bearings and shock absorbers before the season.
• Avoid sharp impacts on potholes - spacers increase the leverage on the suspension.

If the spacers are thicker 20 mm, in winter the risk of suspension damage is higher. We recommend reducing your speed when driving over uneven surfaces.

How often should the spacers be checked?

It is recommended to check the bolt tightness:

• Via 50–100 km after installation (first run-in).
• Every 5,000 km or before long trips.
• After strong impacts (for example, hitting a curb).

Use a torque wrench - over-tightening is just as dangerous as under-tightening! Tightening too tightly can deform the spacer or hub.

Is it possible to make spacers yourself from metal?

Technically yes, but highly not recommended. Homemade spacers:

• ❌ They do not guarantee accurate centering.
• ❌ May crack under load (especially if made from the wrong metal).
• ❌ They will not pass certification for the traffic police.

If you need custom spacers (for example, for a rare bolt pattern), order them from a trusted CNC machined manufacturer. The cost will be higher, but it is justified by safety.