So you're thinking of fitting wheel spacers to your car but not sure where to start?

Maybe you’ve asked around, maybe some random, self-proclaimed 'expert' from the "BMW M Owners" group on facebook or even a workshop or the dealership have told you spacers are no good? Maybe you've even seen two people argue over the fact they are good or bad?

This is one topic that has been debated about for as long as anyone into cars can remember, and to be deadly honest it's for good reason. Like many inventions and products there can be the good stuff and there can be the bad stuff.

What makes a good wheel spacer and what makes a bad wheel spacer? Why does one of the most prestigious and well respected, Motorsport championship winning (LeMans 24 Hour, GT3, etc.) automotive companies in the World, Porsche offer Genuine OEM Wheel Spacers but then someone else from the forum might not suggest running them?

Image above: Genuine Porsche Wheel Spacer Kit

We're here to talk about wheel spacers, are they good or are they bad, to help you identify the right wheel spacers for your car, (If any at all) and what to look out for before purchasing.

1. Material = Quality

When it comes to metals, particularly alloys used in automotive products, how the alloys are produced and formed is extremely important. You have probably heard the terms; Cast, Billet and Forged, maybe numbers like 6061-T6, 7075-T6... What does all this really mean?

Metallurgists agree that a forged or billet piece of aluminum is stronger than cast. The reason being is how that piece is formed. Forging is a manufacturing process where a metal is pressed or forged into great strength. Casting on the other hand involves heating a metal beyond its melting temperature until it is molten and pouring it into a mold, once it solidifies the piece has become cast. If we could put a cross section of these metals under a microscope we would see two very different things, the crystalline structure of the forged piece having an extremely uniform, tight and perfect molecular grain, whereas the cast piece would have large, uneven molecules with no exact pattern. What this translates to is strength. The forged piece being compressed under such extreme force has an extremely high strength-to-weight ratio, meaning it is very light yet very, very strong. The cast piece has a less uniform crystalline structure which means there isn’t as much power in the support it can provide leaving it with a much lower strength-to-weight ratio and more likely to crack or snap under force. It also means no two casting are the same, not even close, creating quality and safety issues when used in certain automotive components.

The numbers 6061-T6 and 7075-T6 refers to the material content in the forged billet or stock, being made up of aluminum, zinc, magnesium, silicon, etc. this also translates to strength and determines the correct use for the material. The T6 part of the indicator refers to the fact the material is thermally treated tempered metal. Both are great alloys used in many applications, 6061 mainly in industrial and 7075 mainly in aerospace. The 7075-T6 has around twice the tensile and shear strength of 6061-T6 making it much stronger and more durable for CNC machined parts that require high strength, especially when very thin, say like a 3mm wheel spacers. Whereas the 6061-T6 has a much higher magnesium content making it not as strong but much more suitable for products that require welding. Both are used in automotive engineering and both are used in wheel spacers.

2. Hub Centric; ‘Hub Centered’

Once a material has been chosen a wheel spacer then needs to be CNC machined to suit the hub of a specific vehicle, some very cheap cast wheel spacers actually have the bore and PCD (bolt pattern and size) in the mold, this is a big no-no. The bore and PCD must be machined to exact and precise tolerances to allow the wheel spacers to perfectly slide onto and off from the hub. We call it the “Goldilocks Effect”, not too tight and not too loose, just right.

Once the spacer has the inner (hub bore), outer (hub diameter) and PCD machined to suit a vehicle there is one last crucial thing to consider, will the new spacer be hub centric? What this means is will the new wheel spacers have an extended bore to carry the original wheel from the center of the hub, like factory. Only hub centric wheel spacers can do this.

Many wheel spacers are not hub centric, meaning they do not spigot onto the wheel at all, leaving all the weight to be carried by the wheel studs or bolts, this is also a big no-no and exactly why many people complain wheel spacers can cause vibrations.

Simply put, if a wheel spacer is made from forged billet, precisely CNC machined to the correct bore and PCD and hub centric, it will not vibrate.

3. Size Matters 

Wheel spacers are made in all different sizes, thicknesses and formats; slide-on, bolt-on, hub adapter, with pressed in studs, etc. from as thin as 2mm all the way up to and even beyond 35mm. When choosing the correct size wheel spacers for your vehicle it is crucial to understand a few things first.

Say you've just purchased a set of Rotiform wheels for your beloved Audi RS3 8V in Nardo Grey, you unbox them and slide the wheels onto the hub, thinking everything is going to be perfect. But to your dismay the new wheel actually just touches the brake caliper. You contact Rotiform and they say that’s the only fitment for your vehicle. You love the wheels and you love your big brakes, what do you do?

The answer is wheel spacers, sliding a 3mm PlusTrack wheel spacers onto the hub solves this problem and still allows your OE hub bore to protrude through the spacer and carry the wheel.

However, say you fitted a BBK (Big Brake Kit) to your VW Golf MK7 R but still want to run the factory Cadiz wheels and they don’t sit flush with the fender then a 3mm spacer won’t cut it. In this instance, the right size spacer is crucial. Each vehicle has a different size and height hub bore, the height and diameter of the hub bore can even vary front to rear which means there is a maximum slip on and a minimum hub centric spacer required to ensure correct, vibration free fitment and hub engagement. That’s where a pre-assembled Flush Fit Kit makes things much easier.

4. Nuts & Bolts

So you have the perfect spacer, but what about the bolts? Many wheel spacer kits on the market don’t even include bolts, some people buy the spacers and attempt to fit them using the vehicles original bolts, this is the biggest no-no. The bolts hold the wheels on and must retain the same amount of thread engagement or turns the bolt has into the hub from the factory. 

A quality wheel spacer kit will include the precise length extended bolts required to ensure correct and safe fitment. The hardware should also meet or exceed manufacturers tensile strengths and standards, most quality wheel spacers will have 10.9 or higher strength bolts with zinc coatings to provide corrosion resistance to OE standards.

5. Fitment

So you’ve got the right spacers, in the right 6061-T6 or 7075-T6 material, they are hub centric and include extended bolts. But are they the right thickness for your vehicle, ride height, wheels and tyres?

The correct thickness wheel spacer will determine the wheel & tyre fitment in relation to the fender, too small will leave an ugly gap and too big may cause tyre rubbing or even worse wheel poke. Measurements can be made between the rim/tyre edge and the fender edge to determine the correct size wheel spacer required, sometimes this can take more than one attempt to get things perfect. Or a pre-assembled Flush Fit Kit can take the guess work out of things, leaving you with perfect fitment while retaining the OEM wheels that came with your vehicle.

Image above: MODE Auto Concepts PlusTrack Flush Fit Kit

MODE PlusTrack Wheel Spacer Kits

MODE PlusTrack Wheel Spacers allow the owner to improve the stance of their vehicle, increase the vehicle track width for better handling and performance and fit larger brakes.

MODE has a complete line of Wheel Spacers to suit Audi, Bentley, BMW, Lamborghini, McLaren, Mercedes, Mini, Porsche, Skoda, VW and more. MODE PlusTrack also caters for many other European models.

MODE PlusTrack Wheel Spacers are made of 7075-T6 Aluminium, the same stuff used in aerospace engineering to make turbine jet impellers which makes MODE PlusTrack Spacers the lightest and strongest spacers on the market!

Click here to get MODE PlusTrack Wheel Spacers

PlusTrack Wheel Spacer Sizes:

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PlusTrack Wheel Spacer Features