When To Replace Brake Discs And Rotors?- 16 Steps to Change

Disc brake systems are the most common type of brake system used in modern vehicles, and they consist of two key components: the brake rotor and the brake caliper. Over time, these parts will wear down from use and eventually need to be replaced. However, knowing when to replace brake discs and rotors can be challenging for many drivers.

Replacing your brake discs and rotors is an important part of vehicle maintenance that should not be ignored. Not only does it ensure your safety on the road, but it also prolongs the life of your braking system and can save you money in the long run.

The rule of thumb is that your brake pads should be replaced between 10,000 and 20,000 miles, and your rotors should be replaced between 50,000 and 70,000 miles. In this article, we’ll cover the signs that indicate it’s time to replace your brake discs and rotors and what you can expect from the replacement process.

When to Replace Brake Discs and Rotors?

Your brakes are crucial to you and your vehicle’s safety, so knowing when to replace your brake pads is important. Generally, you should be looking to replace your brake pads every 10,000 to 20,000 miles. This will keep the wear on them to a minimum and ensure that you have plenty of life left in each pair of brake pads you use for your vehicle. 

Furthermore, after each set of brakes has been replaced, it’s time to rotate the rotors on the car. Rotors should typically be replaced between 50,000 and 70, 000 miles in order for them to maintain peak health and prevent any excess wear from occurring in between replacements.

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How Do I Know Its Time to Replace Brake Discs?

Bent Disc Rotors

Bent disc rotors are one of the most common issues cyclists encounter. This is usually caused by either getting the rotor too hot, damage incurred in a crash, or putting too much pressure on it. For example, if you travel with your bike in the back of your car and rest something on the rotor, this can easily cause it to bend.

Depending on how badly bent the rotor is, you can spot it more quickly than others – sometimes, a rub between brake pads and rotor might occur as the wheel turns.

In general, replacing bent disc rotors is advisable, especially if the cause of bending was due to a crash or incident. However, in other circumstances where milder deformities can be spotted or generally altered without stress, you could try to straighten out these minor imperfections before committing to an entirely new part.

Grinding Sound

It’s important to recognize the signs when your vehicle needs brake repair. Not doing so can lead to serious harm and additional expenses. When you press the brake pedal and hear a loud “CHRRRKKKK.” sound, it’s a telltale sign that your brake pads are worn away and now metal on metal with your rotors. Simply replacing your pads at this point won’t do anything for you in the long run, as they will soon just get chewed up by the old rotor again.


The pulsing sensation that one often feels while braking indicates something is wrong with the brakes. This sensation occurs when the rotors are warped, caused by frequent, heavy brakings or regular usage in high-heat conditions.

In this situation, the brake pad has difficulty adhering to the rotor, causing resistance pulses when applying pressure. The pulses are usually felt throughout the pedal and steering wheel, making it difficult to control the car when braking.

Rotor Cracks

Cracking on a brake rotor indicates an issue that should not be taken lightly. When discussing irregularities on a brake rotor, there are two distinct types of cracks – heat checking and those to the edge. Heat checking is the term used for small hairline cracks that appear on the surface of the rotor due to constant exposure to heat.

This is normal behavior and doesn’t necessarily warrant a new rotor; however, if a crack appears at the edge, it means something entirely different. A crack to the edge can indicate that your brake rotor has reached its life expectancy and should promptly be replaced with a new one.

If you don’t address this issue quickly enough, further damage can build up from having these faulty rotors in place, which could cause major problems down the road. Regardless of type, taking care of these cracks as soon as possible will ensure you have safe brakes when driving your vehicle.

Damage Brake Rotor

When it comes to your car brakes, quality rotors are an important piece of the puzzle. If you notice any damage or grooves on your brake rotors, it may be time to replace them. Damage could occur due to heavy wear of the brake pads and metal backing plates that can scrape up the rotor surface over time. In addition, exposure to road debris, rust, and corrosion can also damage the rotors.

This means when you change out your pads and rotors, you should always switch out all of the front and rear sets for a uniform braking experience.

It’s also beneficial to distinguish between a warped rotor and a grooved one – as they don’t necessarily mean the same thing. A warped rotor is uncommon, whereas a grooved one is more likely due to negligence or continuous use without checking its condition.

Ultimately, if there’s visually any damage on the rotors, be sure to change them out immediately so that your car has optimal stopping power.

Things to Mind While Changing Brakes Dics and Roots

Perfect Size

It is important to note that changing rotor size can affect the performance of your bike’s disc brakes. Generally, if you intend to use your brakes heavily or are a heavier rider, it is best to choose a larger rotor size to handle the increased brake force and heat buildup.

Shimano and SRAM both recommend larger rotors on the road, with 140mm as an ideal choice for cyclocross. Furthermore, Focus has reported that they found 160mm rotors preferable to 140mm due to their better-dissipating heat.

Overall, whether you decide to go with the more common 140mm or upgrade to 160mm for more braking power and improved heat dissipation is up to personal preference. But remember that not all bikes have been designed for these sometimes larger sizes, so you may need specific adaptors or components for larger rotors to be compatible with your bike.

How to replace brake discs

Replacing brake discs (also known as brake rotors) is a task that requires some mechanical skill and the right tools. It’s essential to follow the manufacturer’s guidelines and exercise caution to ensure safety. Here’s a general guide on how to replace brake discs:

Note: This guide provides a basic overview. Consult your vehicle's manual and, if you're not comfortable with the process, consider seeking professional assistance.

Tools and Materials:

Tools and MaterialsDescription
Jack and Jack StandsUsed to lift the vehicle off the ground safely.
Lug WrenchFor loosening and tightening lug nuts on the wheel.
Socket and Ratchet SetNeeded for removing bolts and fasteners.
C-Clamp or Caliper ToolUsed to compress the brake caliper piston when installing new brake pads.
Brake CleanerUsed to clean the new brake discs and parts.
New Brake DiscsReplacement brake rotors for your vehicle.
New Brake PadsReplacement brake pads (recommended to replace with new discs).
Torque WrenchTo ensure proper and consistent lug nut tightening.
Gloves and Safety GogglesFor hand protection and eye safety during the process.

Step-by-Step Guide:

  1. Prepare the Vehicle:
    • Park your vehicle on a flat and safe surface.
    • Engage the parking brake and chock the wheels to prevent rolling.
    • Loosen the lug nuts on the wheel with the brake discs you’re replacing, but do not remove them.
  2. Lift the Vehicle:
    • Use a jack to lift the vehicle off the ground.
    • Place jack stands under the vehicle to secure it.
  3. Remove the Wheel:
    • Completely remove the lug nuts and take off the wheel.
  4. Access the Brake Components:
    • Locate the brake caliper, which holds the brake pads and needs to be removed to access the brake disc.
    • One or two bolts may hold the caliper in place, depending on your vehicle. Use your socket and ratchet set to remove these bolts.
  5. Remove the Brake Caliper:
    • Gently slide the caliper off the brake disc, being cautious not to damage the hose.
    • Hang the caliper using a wire or bungee cord to prevent straining the brake hose.
  6. Remove the Brake Disc:
    • A few screws or the wheel may secure the brake disc. If there are screws, remove them.
    • Tap the brake disc gently with a rubber mallet to break it loose. If it’s stuck, you may need to use penetrating oil and more force.
  7. Install the New Brake Disc:
    • Clean the hub surface and install the new brake disc. Ensure it fits snugly.
    • If the new disc has a protective coating, remove it using brake cleaner.
  8. Reinstall the Brake Caliper:
    • Carefully place the brake caliper over the new disc and align it with the brake pads.
    • Secure the caliper in place with the bolts you removed earlier.
  9. Brake Pad Inspection:
    • While the caliper is off, inspecting the brake pads is a good opportunity. If they’re significantly worn, consider replacing them along with the brake discs.
  10. Reinstall the Wheel:
    • Place the wheel back on the vehicle’s hub.
    • Tighten the lug nuts hand-tight initially.
  11. Lower the Vehicle:
    • Carefully remove the jack stands and lower the vehicle to the ground.
  12. Tighten Lug Nuts:
    • Use a torque wrench to properly tighten the lug nuts to the manufacturer’s recommended torque specification. This is important for safety.
  13. Bedding-in Process:
    • After replacing the brake discs and pads, it’s recommended to perform a “bedding-in” process. This involves gently braking to heat and seat the new components. Follow your manufacturer’s recommendations for this process.

Remember that this is a general guide, and the process might vary depending on your vehicle’s make and model. If you’re not comfortable with any step, it’s always best to seek professional help. Properly functioning brakes are crucial for your safety and the safety of others on the road.

Maintenance Tips

Proper maintenance is essential for keeping your vehicle in good condition and ensuring your safety on the road. Here are some maintenance tips to help you take care of your vehicle:

1. Regular Oil Changes:

  • Follow your vehicle manufacturer’s recommended oil change interval.
  • Regular oil changes help keep your engine running smoothly and extend its lifespan.

2. Check Fluid Levels:

  • Regularly check and top up fluids such as coolant, brake fluid, transmission fluid, and power steering fluid.
  • Low fluid levels can lead to mechanical problems and reduced performance.

3. Inspect Tires:

  • Check tire pressure regularly and maintain it at the recommended level.
  • Inspect tires for signs of wear and rotate them according to your vehicle’s manual.

4. Brake System Maintenance:

  • Monitor brake pad thickness and replace them if they’re worn.
  • Regularly inspect brake fluid levels and ensure there are no leaks.

5. Air Filter Replacement:

  • Replace the air filter as recommended in your vehicle’s manual.
  • A clean air filter improves fuel efficiency and engine performance.

6. Battery Care:

  • Check the battery terminals for corrosion and clean them if necessary.
  • If your battery is old or weak, consider replacing it before it fails.

7. Regular Maintenance Schedule:

  • Follow your vehicle’s recommended maintenance schedule outlined in the owner’s manual.
  • Adhering to the schedule helps prevent major issues and prolongs the life of your vehicle.

8. Transmission Maintenance:

  • If your vehicle has an automatic transmission, have the transmission fluid changed at the recommended intervals?

9. Check Belts and Hoses:

  • Inspect belts and hoses for signs of wear, cracks, or leaks.
  • Replace any damaged belts or hoses to prevent breakdowns.

10. Keep It Clean:

  • Regularly wash and wax your vehicle to protect its paint and finish.
  • Clean the interior to prevent dirt buildup and maintain a pleasant driving environment.

11. Maintain Cooling System:

  • Ensure the radiator and cooling system are in good condition.
  • Flush the radiator and change the coolant as recommended.

12. Listen and Observe:

  • Pay attention to any unusual noises, vibrations, or changes in how your vehicle drives.
  • Address issues promptly to prevent further damage.

13. Drive Responsibly:

  • Avoid aggressive driving, which can put extra strain on your vehicle’s components.
  • Smooth acceleration and braking can reduce wear and tear.

14. Use Quality Fuel:

  • Use the recommended octane level of fuel for your vehicle.
  • High-quality fuel can help maintain engine performance.

15. Store Manuals and Records:

  • Keep your vehicle’s owner’s manual and maintenance records in a safe place.
  • Records can help track maintenance history and assist with resale value.

16. Winter and Seasonal Maintenance:

  • Prepare your vehicle for changing seasons by checking items like the battery, tires, and antifreeze before winter.

Regular maintenance can significantly extend the lifespan of your vehicle and minimize the risk of breakdowns. Following these tips and referring to your vehicle’s owner’s manual for specific guidance can help you keep your vehicle running smoothly and safely.

Frequently Asked Questions [FAQs]

1. How Do I Know If I Really Need New Rotors?

When the brake pads conform to the uneven surface of warped rotors, the steering wheel may vibrate or pulse. In this case, it may be necessary to replace the rotors to resolve the issue.

2. How Often Should I Replace My Brake Discs And Rotors?

The frequency of replacement depends on the wear and tear of your brakes and the type of driving you to do. For instance, if you do a lot of city driving or drive in stop-and-go traffic, your rotors will wear out faster than normal. On the other hand, if you mostly drive on highways, your rotors will last longer. Generally, it is recommended to replace brake discs and rotors every 50,000 miles or so.

3. Can I See If My Rotors Are Bad?

Yes, you can see if your rotors are bad. While visually inspecting the brakes, look for signs of wear or damage. Any deep grooves, cracks, or metal shavings on the rotor surface indicate that they need to be replaced. Additionally, check for any pulsing or unusual vibrations when braking — this could indicate warped rotors and uneven brake pad contact. Finally, listen for any squealing or grinding noises — these could be signs of worn-out brake pads.

4. What Is The Lifespan Of A Rotor?

The average lifespan of a rotor is around 50,000 to 70,000 miles. However, this varies depending on the driving habits and conditions of the vehicle. For example, if the vehicle is driven in areas with heavy traffic or frequent braking, the rotors may wear out sooner than expected. Additionally, if the brake pads are not replaced frequently enough or are of low quality, this

5. How Many Mm Is A Bad Rotor?

The thickness of a rotor or brake disc is one of the primary indicators of its health. Rotors should typically be replaced at or below the manufacturer’s minimum specification, which is usually between 8-11mm. If the rotor has experienced extensive wear and tear over time, it may be necessary to replace them sooner than this.


Brake rotors and pads are essential components of any vehicle’s braking system. Ensuring they are in good condition is key to achieving optimal stopping power. To do that, you will need to replace them every so often and make sure to maintain them properly. Doing this will help ensure your safety and the longevity of your car’s brakes.

John D. Archer