What are Shims on a Car

Shims on a car are thin pieces of material placed between the brake pads and the rotor to adjust the spacing and improve the performance of the braking system. Shims are commonly made from metal or rubber, and they help to reduce noise and vibration while increasing the lifespan of the brake pads.

Maintaining a car’s braking system is of utmost importance, as it plays a crucial role in keeping both the driver and passengers safe while on the road. Normally, the brake pads and rotor come into contact with each other during braking, causing heat and wear.

However, using shims helps to create a little bit of space between the two, which minimizes the heat and wear, and thereby extends the life of the brake pads. Additionally, shims help to prevent brake squeaking and vibrations by dampening the noise caused by pad vibration. Therefore, shims are essential for a well-functioning braking system that ensures safety and comfort on the road.

What are Shims on a Car: A Comprehensive Guide

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Types Of Shims

Shims are small, thin pieces used to fill the space between two surfaces that otherwise wouldn’t fit properly. They play an essential role in keeping car parts from shifting during operation. They’re often made of metal or plastic and come in various shapes and sizes.

In this article, we will focus on the different types of shims notably the deck shims and tapered shims.

Deck Shims

Deck shims are wedge-shaped shims designed to help level out a car’s platform. They’re commonly used to fit parts onto uneven surfaces and ensure that they’re fastened securely.

  • They help prevent sliding and shifting during movement.
  • They can handle heavy pressure and weight.
  • They’re easily adjustable to suit different applications.

Deck shims are available in metal and plastic varieties, with the appropriate type depending on your specific needs.

Tapered Shims

Tapered shims are a type of wedge-shaped shim that may be either thicker at one end or angled. They offer a more comprehensive pressure distribution than other types of shims and are ideal for preventing slippage caused by high levels of vibration or irregularities.

  • They provide a solid base with reliable support.
  • They are perfect for settling heavy and large machinery to mitigate vibration.
  • They can be stacked for greater versatility.

Tapered shims are usually made of stainless steel, polypropylene, or pvc. Because of their versatility, they can be utilized in different applications. In addition, they can withstand the rigors of high-pressure environments with ease.

As you can see, shims play a vital role in a car’s functioning, ensuring that each part fits together correctly. Regardless of the specific type of shim you use, it’s essential to choose the right type for your specific needs.

With so many options on the market, selecting the right one can be a bit challenging. By learning about the various types of shims available, including deck shims and tapered shims, determining which one suits your application will be a breeze.

Signs That Your Car Needs Shims

Overview Of Common Symptoms Associated With A Car That Needs Shims

If you’re experiencing any of the following signs, your car may need shims. Shims are thin, tapered, and commonly made of metal or plastic. They are designed to match and balance components, enhancing the alignment and function of your car’s wheels.

Here are the most common symptoms that your car needs shims:

Uneven Tire Wear

One of the most telling signs that your car needs shims is uneven tire wear. This can result in the tires wearing out faster than usual. You may notice a difference in the wear patterns of your tires, with one tire more worn than the others.

If you notice accelerated wear on the outer or inner edge of your tires, it could be time to install shims.

Abnormal Steering

If your car is experiencing abnormal steering or drifts to one side of the road, it may need shims. Shims can rectify the issue by realigning the steering components. Additionally, if you feel vibrations through the steering wheel, place your hand on the tire while driving, and if it’s shaking, it’s a clear indication that your car needs shims.

Noisy Suspension

Sometimes, you may experience weird noises coming from your car’s suspension system. Creaking or rattling noises indicate that your car’s suspension system is not correctly aligned and needs adjustment via shims. Shims can help to eliminate the noises and bring your car’s handling back to where it should be.

Brakes That Need Adjustment Frequently

Do you often find yourself needing to adjust your car’s brake pads frequently? If the brake pads need constant adjustment, they can wear out more quickly than usual, requiring costly repairs. The brakes may also be worn out unevenly, leading to a vibrating feel when braking.

If you notice this problem, it’s recommended to have shims installed to ensure your car’s brake pads wear evenly, improving overall braking performance.

Paying attention to the above signs is key in ensuring your car’s shims and alignment are up to par. Monitoring tire wear, abnormal steering, noisy suspension and frequently having to adjust brakes can all signify that your car needs shims.

By taking the necessary steps to install shims, you can prolong your car’s lifespan and save a considerable amount of money in the long run.

How and Why to Install a Neck Shim on a Fender Bolt On Neck

How To Install And Adjust Shims

Tools Needed

Before you start to install or adjust shims, you need to have the following tools ready:

  • Socket wrench set or adjustable wrench
  • Set of feeler gauges
  • Torque wrench

These tools will assist you in the shim installation and adjustment process.

Step-By-Step Explanation Of Installation Process

The installation process of shims can be broken down into the following simple steps:

  • Locate the shim location: you can find the shim location by checking the manufacturer’s manual.
  • Remove the tire: to install shims, you will need to remove the tire of the car.
  • Determine the thickness of the needed shim: use a feeler gauge to measure the thickness of the needed shim.
  • Install the shim: place the needed shim behind the hub assembly and insert the bolts.
  • Reinstall the tire: after installing the shim, reinstall the tire and hand tighten the bolts.
  • Use a torque wrench: finally, use a torque wrench to tighten the bolts to the recommended torque.

Tips For Proper Adjustment Of Shims

Proper adjustment of shims is crucial to ensure that your car runs smoothly.

  • Always refer to the manufacturer’s manual for the recommended shim adjustment.
  • Use a feeler gauge to check the clearance between the shim and hub assembly.
  • Adjust the shims gradually until reaching the correct settings to avoid damaging tire and brakes.
  • Recheck clearance after tightening the bolts to avoid over-tightening.

Common Mistakes To Avoid

Make sure you avoid the following common mistakes when installing or adjusting shims:

  • Failing to use the right measurement tools.
  • Over-tightening the bolts and damaging the tire and brakes.
  • Ignoring the recommended shim adjustment settings.
  • Adding shims without removing old shims, leading to incorrect measurement.

Installing and adjusting shims may seem complicated, but it is manageable if you follow the recommended steps and guidelines. Always remember to have the proper tools, use the correct measurement, and refer to the manufacturer’s manual, and you will have a smooth and safe ride.

Pros And Cons Of Using Shims On A Car

Shims are thin plates made of metal or plastic that are used to achieve proper alignment and balance in the wheels of a car. These shims fit between the wheel and the car’s hub, allowing for improved handling and stability.


Using shims on a car can provide several benefits, including:

  • Improved handling: shims can help to fine-tune the alignment of the wheels, resulting in better handling and control on the road.
  • Better balance: if a car’s wheels are not properly balanced, it can lead to uneven tire wear and a decrease in fuel efficiency. Shims can help to balance out the wheels and prevent these issues.
  • Increased safety: properly aligned wheels can also help to improve overall safety while driving, as the car will be less prone to slipping or skidding on the road.
  • Cost-effective: installing shims is a more affordable option compared to other methods of wheel alignment.


However, there are also some potential drawbacks to using shims on a car, such as:

  • Added vibration: depending on the material of the shim and the car’s suspension system, using shims may result in added vibration and noise while driving.
  • Limited adjustment: shims can only provide a limited amount of adjustment and cannot fix more severe wheel misalignment issues.
  • Labor-intensive: installing shims can be a labor-intensive process that may require the aid of a professional mechanic, making it a more costly option overall.
  • Potential damage: if shims are not installed properly, they can cause damage to the car’s wheels or suspension system, leading to even more issues.

Shims can provide some benefits for wheel alignment and balance, but they should be used with caution and only after weighing the potential downsides. If you are experiencing issues with your car’s handling or suspension, it may be best to consult with a trusted mechanic to determine the root cause and the best course of action.

Frequently Asked Questions On What Are Shims On A Car

What Are Shims On A Car Used For?

Shims on a car are used to adjust the spacing between brake pads and rotors. They are thin layers of material that are inserted between the pad and caliper mounting bracket. Shims help reduce vibrations and noise, ensuring smooth operation of the brake system.

Can I Drive Without Shims On My Car?

It’s not recommended to drive without shims. Shims help to reduce brake noise and vibrations and keep the brakes cooler, improving longevity. Without shims, you may experience loud brake squealing or rough braking and the brakes may start to overheat, potentially leading to brake failure.

How Often Should Shims Be Replaced?

Shims should be checked and replaced during each brake pad replacement service. They have a lifespan similar to brake pads and may need replacement if they are worn out or damaged. Regular inspection can help identify any issues and prevent brake system problems.


Shims are small, thin pieces of material used to adjust the alignment of different parts of a car’s suspension system. They are essential in ensuring that the car performs well on the road and that the tires wear evenly. Shims are used to shim the wheel bearing for proper clearances and adjust the camber, caster, and toe angles.

It’s important to note that shims should only be installed by a professional mechanic. While shims may seem like a small and insignificant part, they play a crucial role in the overall performance of the car. Understanding their purpose and how they work is important for any car owner who wants to keep their vehicle in top-notch condition.

So if you notice any issues with your car’s suspension system, make sure to get it checked by a certified technician who can diagnose and resolve the issue.