Black anodised hub-centric wheel spacer

What Happens If You Use the Wrong Wheel Spacer Thickness?

Wheel spacers can completely transform the look and handling of your car — but only if you choose the correct thickness. Using spacers that are too thin or too thick can lead to rubbing, vibration, unsafe wheel fitment, and even long-term mechanical damage.

In this guide, we break down exactly what happens when the wrong spacer thickness is used, how to spot the warning signs, and how to choose the right size the first time.

Why Spacer Thickness Matters

Wheel spacers adjust your wheel’s position by pushing it outward from the hub.
This affects:

  • Wheel arch clearance

  • Suspension clearance

  • Brake caliper clearance

  • Wheel bearing load

  • Overall stability and handling

A few millimetres can make the difference between perfect fitment and serious problems.

What Happens If the Spacer Is Too Thin?

1. The Wheel Still Hits the Brake Caliper or Suspension

If your main goal is clearance, a spacer that’s too thin won’t create enough space between the wheel and:

  • Big brake kits

  • Brake caliper faces

  • Coilovers or struts

Results:
Persistent rubbing, metallic scraping noises, or the wheel refusing to rotate freely.

2. You Won’t Achieve Flush Fitment

Trying to improve stance? A spacer that's too thin can leave the wheel still sitting too far inside the arch.

Results:

  • Sunken wheels

  • Weak visual stance

  • No improvement in appearance

3. Handling Improvements May Be Negligible

A very thin spacer (e.g., 3–5mm) may offer minimal track width increase, meaning little or no improvement in stability or cornering feel.

What Happens If the Spacer Is Too Thick?

1. The Wheels May Poke Past the Arch

A spacer that’s too thick pushes the wheel too far outward.

Results:

  • Tyres sticking out awkwardly

  • Excessive poke

  • MOT or inspection issues (in some regions)

  • Unwanted spray from tyres in wet conditions

2. Tyre Rubbing on the Arch or Liner

If the wheel sits too far outward, the tyre may hit the arch:

  • Over bumps

  • At full steering lock

  • With passengers or cargo

This can quickly damage tyres — and tyres rubbing through the arch liner is extremely common.

3. Increased Wheel Bearing Wear

Too much spacer thickness adds leverage against the wheel bearing.

Effects over time:

  • Premature bearing wear

  • Potential bearing failure

  • Extra noise or vibration

While mild increases are normal with spacers, excessively thick spacers amplify the load significantly.

4. Wheel Bolts or Studs May Become Too Short

If you don’t account for spacer thickness, your bolts may no longer seat deep enough into the hub.

You need at least 6.5 full turns (bolts) or full nut engagement (studs).

Too-thick spacers can result in:

  • Loose wheels

  • Bolt shear

  • Dangerous driving conditions

5. Steering Feel and Stability May Suffer

Very thick spacers alter scrub radius and steering geometry.

Symptoms:

  • Poor steering feedback

  • Light or unstable steering

  • Tramlining

  • Increased vibration

What Happens If You Use Spacers of DIFFERENT Thickness Left to Right?

This should never be done.

Consequences:

  • Uneven handling

  • Pulling to one side

  • Tyre wear issues

  • Unsafe weight distribution

Front and rear can differ — left and right must not.

Warning Signs You’re Using the Wrong Spacer Size

Look out for:

  • Rubbing noises when turning or hitting bumps

  • Wheel vibration at speed

  • Tyres scraping inner or outer arches

  • Steering pull

  • Wheels difficult to torque correctly

  • Visible wheel poke

  • Brake caliper clearance issues

If you notice any of these, remove and reassess immediately.

How to Choose the Correct Spacer Thickness

1. Measure your arch gap

Use a straight edge and measuring tape to determine how many millimetres you need for flush fitment.

2. Check inner clearance

Make sure the wheel clears the caliper or suspension.

3. Know your desired look

Flush, mild poke, or purely functional?

4. Stay within sensible limits

Most cars run safely:

  • Front: 5–15mm

  • Rear: 15–25mm

(Always measure your specific vehicle.)

5. Always choose hub-centric spacers

These reduce vibration and improve safety.

Final Thoughts

Using the wrong wheel spacer thickness can lead to rubbing, vibration, premature wear, or unsafe driving. But with simple measurements and the right spacer type, you can achieve:

  • Perfect flush fitment

  • Better handling

  • Improved stance

  • Safe, balanced wheel installation

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