How Smooth Should Brake Rotors Be?

How Smooth Should Brake Rotors Be?

A good braking system is dependent on the performance of many components; among this is the brake rotor. These need to remain in a particular state in order to perform at optimum. For example, smooth brake rotors perform better than those with residue r build up. We are going to discuss brake rotors in length, tell you what they are, how long they should last and give you some tips on some signs that your rotor might have some issues.

There are instances when oil residue, build up, and deposits may form on the surface of rotors which might negatively influence braking performance. These residues might not hurt the disc itself, but they will affect the brake pads in this disc braking system. You are always advised to clean your rotor surfaces as maintenance. In fact, you are advised to always clean brake components of residue to ensure the system works properly.

What are brake rotors?

Brake rotors also known as brake discs are the round or circular part of your brake system connected to each wheel. These discs are designed with a specific thickness with differently set slots and holes depending on the type of rotor it is. Yes, there are different types of rotor. But before we get into that, let us first briefly discuss what brake rotors do. Simply put, these turn kinetic energy, in the forwards motion into thermal energy or what we all know as heat. First off the braking system in your vehicle is a pressure operated system. For example, pushing down the pedal; during braking generates pressure within the system and runs through the master cylinder. Through a series of hoes, this pressure is distributed to the front rotors, either side is possible. This braking fluid, which is under pressure, closes the pads onto the rotor and causes friction. If you’ve been keeping up, you’ve probably realized this friction will result in heat, which the brake discs if in good form, will easily and readily dissipate to ensure the system can continue running. If you are lost, we can simply summarize the function of brake discs as thick metal plates that are an essential component to braking systems whose main function is to take away heat generated during braking.

Thus, more braking means more heat. So how do you know if you are putting your rotors under stress? Well, there are certain practices such as stoop and go driving especially in city environments that lead to wearing in the brake discs.

Remember when we mentioned that there were different types of brake rotors? Well, this difference is created by the different material brake rotors there are and the various design features found on rotors. First we have the difference in material. Majority of rotors are cast iron in nature, reliable and reputed with good performance. However, cast iron doesn’t work for all types of vehicles or some with special needs. Some popular material examples include steel which is excellent at cooling but warps easily: next is aluminum which is quite light but melts like butter. Others like high carbon are great all around but very price. The list goes on with ceramic and even layered steel. When stuck between the types of brake disc to get based o material, consider your driving conditions in accordance with the material. If the cost justifies the expense, then by all means get the brake disc you think is best, however, getting high carbon disks for your exhibit car might be somewhat too much.

Based on the features and design, there are many types of rotors. The most popular include the following:

  • Good old smooth and blank. As the name suggests, these are a plain metal surface rotors that are a popular choice for many drivers. They are cheap and get the job done. These are a great choice for not aggressive drivers and really majority of cars regardless of their nature, luxury or regular. It must be said however, OEM, Original manufacturer Equipment in smooth and black are better than aftermarket parts. These are often made of steel, warp sooner and often damage brake pads.
  • Slotted rotors feature a set of slots that circumvent the exterior rotor surface. These are designed for vehicles that require great stopping power like heavy duty trucks or even SUVS. They work by drawing more air into the gaps or slots, helping with the heat dispersion and generally improving the cooling process, additionally, these slots help chuck excess glaze from the pads or brake debris that usually comes about at high temperatures. However, because these are slotted, they do not last as long as the blanks.
  • Next we have the drilled brake discs that have holes instead of spiraling slots on the external surface through to the other end of the rotor. These are specifically made for wet or slippery driving conditions. The holes drilled onto these babies help to dissipate heat generated from driving on wet roads. However, they aren’t great for high performance breaking that generates a large amount of heat.
  • Lastly we have the drilled and slotted brake discs that combine the holes and spiraling slots for the high performance hybrid that is the drilled and slotted brake disc. Additionally, the combination of holes and slots is meant to greatly increase breaking capacity at higher speeds.

When to change brake rotors

Average life of brake rotorsThe braking system is a series of simple yet complicated workings and components. These components are constantly under a lot of stress and must be maintained properly so they can continue to function in prime conditions. Before you replace your rotors, it is important that you are sure they are the problem by properly troubleshooting them.

Some of the most popular issues with brake rotors are wear related. However, other common reasons your rotor might be underperforming include the following.

First, is warping which is not quite what you are picturing. In fact, warping is used by pros and mechanics to describe a no longer even rotor surface. The most likely reason why your rots are warping is build up on the rotor surface. Over time, residues and other components accumulate on the surface of the brake rotors become influential enough to cause warping. Sometimes, warping is used to describe the phenomenon when less dense parts of the disc wear quicker than the more dense parts, leading to distortions on the rotor disc. The good news however is you don’t have to worry about this problem if you have good quality rotors in place: it is likely to occur in poor quality rotors.

Second, we have galling which is also a common poor quality rotor problem. It may also be known a ribbing or scoring, This issue develops fro insufficient hardness which means the rotor surface is defenseless against gouging by the pad. This is a dangerous occurrence as galling will decrease the efficiency of your brakes and make them slower.

Last is corrosion that is common to the most common rotor material, cast iron. Rusting is a problem when it comes to rotors, but not as serious as you would thing. The rust often eats away at the brake pads making the rotor even most prone to corrosion. Usually, those who neglect the rust are often the one who suffer most from rust associated rotor damage. This rust can penetrate the rotor deeper than you can imagine, making them pitted and scored and less effective than ever.

TIP: Brake rotors are essential for safe driving. If you notice a problem with your rotors, fix it or have them changed for your sake and the sake of other drivers.

Often, there are signs that accompany a bad or failing brake rotor. Some of the most common ways to tell you need to change your brake rots or need a repair include the following.

  • First off is the classic noisy brake which is a reliable way of identifying braking issues. Usually wear and warping are responsible for squealing and squeaking noises. In fact, warping is responsible for many instances of noise and strange sounds from the brakes
  • A pulsating brake is a good indicator you might have faulty discs. Usually, the only time you feel break pulsations is when you engage ABS. Otherwise, you should feel the vibrations on the pedal or irregular shaking and vibrations when applying the brakes.
  • Physical inspection is one of the most effective ways to establish rotor health. It might not be a symptom of a failing brake rotor but regular checks and inspections will help identify issues well before they get serious.
  • Lastly, any score or groove marks on your rotor are a sign of bad discs. These are often created on the surface of the rotor due to constant contact with your brake pads. Be very careful if you notice these grooves or any scoring as they could result in a decreased ability to slow your vehicle down. This increase in stopping distances can also be a great way to identify progressed brake rotor damage

If your brake rotors are damaged past repair then they will have to be replaced. Replacements made are usually with the choice of variations we discussed earlier However, it not exactly a cheap expense. You can expect to spend anything from 150 to 200 dollars per axle for the labor. However, the total cost could come to 250 to 500 dollars. This price will vary depending on a number of factors.

In case you fancy yourself the professional or if you know your way around a car, you could make the replacement yourself. This process is pretty straightforward and will take you all of a maximum 10 minutes. In order to replace the brake motors on your vehicle, begin by loosening the lug nut then jacking up your vehicle while securing it using jack stands. Next, you want to depress your brake pedals a total 20 times and the residual pressure is released. You can then remove all the lug nuts then take off the wheel. Continue by unbolting the two brake caliper fasteners which you will find at the rear of the caliper.

Removing the bottom fastener first will make it easier it remove the brake pads as well. Take off the pads and unbolt your top caliper fastener. Afterwards, unbolt your caliper from the two bracket bolts on your steering knuckle. Next, you will have to remove the caliper and hang it from your vehicle. This can be done using the strut. Do not allow the caliper to nag from the brake line as it could damage the lines. After you accomplish his, you will have to take off the disc from the wheel studs and apply antiseize lubricant on the axle hub. Now comes the replacement part where you will check one last time that your replacement rotor matches the old rotor. You can then proceed to lean the surface f the new rotor before installing it. We recommend that you use brake cleaner spray which works well against many oil related stains and residues. Don’t forget to install your brake pads here if you need to. Now you need to put everything back in place. Don’t forget to top up the brake fluid and ensure the wheel is replaced properly.

Why your rotors need to be smooth

Smooth rotors are rotors that maintain their even thickness or even surface shape even after stresses. When rotors become warped or have any interference to the surface, they have difficulty performing as they should.

Average life of brake rotors

We have already established that the rotor experiences intense stress during operation and is prone to a number of deteriorates. However, you can expect a good set of brake rotors to last you anywhere between 30K to 70K miles. However, on average, you should expect 50K miles service period. It is important to note that these brake rotors only last as long as you care for them For example, there are some steps you may take in order to make the discs last longer. These include adjusting your driving style to consider the rotors, trying to change your driving conditions; like avoiding terrain that will overly stress the brake rotors unless they can handle it, maintaining your tires so that they can work at optimum in tandem with the brakes and frequently replacing the brake pads as needed. Doing this will not mean your rotors will last forever, however, they will last longer than they would have if neglected.

Final word

Brake rotors are an important part of driving. Without them, stopping safely would be impossible. Because many modern cars carry this disc brake system, it is important that car owners understand the component fully so as to practice safe driving. If you ever suspect your rotors are no longer functional, ensure to see a pro for replacement or even to it yourself. Either way, rotors are essential and in good condition at that or every driver.

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Steven Reilly
Steven Reilly is a qualified mechanic and his passion for cars goes beyond just the technical aspects. He is also an amateur racer and all round car enthusiast. When he is not driving them, he can often be found in his garage under the hood of a rare model. Steven Reilly has lost track of the number of hours he has spent setting up his fine collection of rebuilt models. He believes that cars can provide a constructive and fun opportunity to teach the youth important life skills. In line with this, he is developing a community outreach program, potentially dubbed ‘Cars for change'.


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