What Causes Grooves in Brake Rotors? Is There a Fix?

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Brake rotors are one of the most important components of the braking system of your car; without them, you cannot even stop your car. Brake rotors should be in top-notch condition for effective braking. Having grooves on the rotors is common, but you should not ignore it, considering the issues it causes, including impacting braking distance. 


What Causes Brake Rotor Grooves?

Grroves are long, deep lines that are cut into the surface of the brake rotors. There can be multiple causes behind these grooves. I have explained all of them below:

Presence of Dirt and Impurities – Usullay debris ends up on the brake pads and the rotors and causes grooves. For example, if sand particles are present on the surface of the brake pads or rotors while braking, those sand particles will create friction, resulting in grooves. 

Too Much Hard Braking – Too much hard braking can cause grooves due to excessive heat. I have personally experienced this. I used to drive a bit recklessly and brake hard often; my car’s rotors developed grooves, and I had to replace them just after a few thousand miles. 

Typical Wear and Tear – It’s common for brake rotors to develop grooves over time due to friction and heat that they have to bear for years. But keep in mind it happens after the car is driven around 25000 to 55000 miles (40000 to 90000 KMs).  

Worn-Out Brake Pads – When brake pads undergo wear, their backing plates become exposed and start rubbing against the rotor while braking. Worn-out brake pads are one of the fastest ways to develop rotor grooves, and apart from grooves, they can cause a squeaking sound while braking. 


What Are the Effects of Grooved Brake Rotors?

Grooved brake rotors directly impact your braking performance, which is a significant part of your overall driving experience. The effects are mentioned below:

Longer Stopping Distance – Grooves create an uneven rotor surface, causing the pads not to contact the rotor completely, which results in less braking power, which eventually causes the car to have a longer stopping distance. 

Wobbling and Vibration – If the rotors have grooves, braking during high speed causes wobbling and vibrations in the car. When my car’s rotors got grooves, I faced this situation. The wobbling was severe enough to shake my dashcam. Apart from this, some people can also experience pedal pulsations.

Accelerated Brake Pad Wear – The brake pads need perfectly flat rotors to last thousands of miles. Even a minor difference in the surface can cause the brake pads to wear faster and incur damage. 


How to Prevent Grooved Rotors?

To prevent grooved brake rotors, avoid reckless driving; it makes you use too much brakes, which can cause excessive heat that results in grooves. Avoid hard braking as well, and make sure you frequently inspect the rotor, caliper, and brake pads for debris; if found, clean it before driving the car. Additionally, make sure your brake pads are not worn out. 


How to Fix Grooved Rotors?

If your rotors are grooved, you can resurface them on a lathe machine. Keep in mind resurfacing will reduce the thickness of the disc. Your discs should have the minimum thickness required mentioned on the rotor. Most manufacturers set a minimum thickness for a rotor, which is indicated on the rotor itself. For instance, if a rotor must be at least 1.5 mm thick, you will find ‘Min. TH=1.5’ marked on it. 

In case your rotors do not have this information, contact your car’s manufacturer or local dealer to get the information. 

Do not go below the minimum required thickness; your rotors can break catastrophically if done. 

Note: If your rotors cannot be resurfaced due to thickness or any other reason, I recommend you replace them along with a new set of brake pads. 


Can I Drive With Grooved Rotors?

If the grooves are not too deep, you can drive your car with them. In fact, when I had grooved rotors, I didn’t even notice them for several hundred miles.

I became aware of the issue when I reached the freeway and experienced wobbling during high-speed braking. Make sure you drive slowly and be gentle on the brakes. If you plan to drive at decent speeds, do not drive with grooved rotors; replace them as soon as possible. 


What Happens if You Put New Brake Pads on Grooved Rotors?

If your car’s brake rotors are damaged or grooved, the brake pads previously used to clamp onto them won’t be able to contact the rotors properly. Eventually, this affects the car’s stopping ability and braking performance. In this case, installing new brake pads won’t make a significant difference as they won’t be able to get in contact with the rotor that well. 

Note: Here is a YouTube tutorial for you if you want to install new brake pads on your vehicle. 


How to Determine if Brake Rotors Need to Be Replaced

If your car is wobbling, vibrating, making a squeaking noise, or even your vehicle is pulling to one side while braking, you may need to replace the brake rotors. 

To manually inspect the rotors, make sure they have the minimum required thickness recommended by the manufacture and have no cracks or warping.


How Much Does It Cost to Replace Brake Rotors?

Brake rotor prices are based on the brand and the size; they are $250-$400 per axle on average and can even go up if the car is expensive.


Are brake Discs (Rotors) covered under warranty?

Rotors are a wear and tear part just like the clutch plates; the manufacturers do not replace them under warranty unless they are damaged due to manufacturing defects.


Read More

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