Everything You Need To Know To Find The Best Rotor Motor

This brake tech guide was written to help you decide which avenue to go down in regard to your Pontiac's brake upgrades. We've talked with some of the biggest names in the performance disc-brake industry, including Brembo, Stoptech, and Wilwood, as well as Master Power Brakes. For Part I, we discuss rotors because there is a lot of ground to cover here. Part II will examine friction materials (pads), calipers, and fluids.

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In operation, the brakes slow the rotation of the wheel and tire by converting kinetic energy into thermal energy, thus producing heat. The quest for braking performance involves the braking system's efficiency in dealing with heat and its ability to convert energy. The role of the tires in the braking process cannot be understated, however, as maintaining their grip on the pavement is paramount to stopping your Pontiac.

Before upgrading your brakes, there are a few important factors you should consider: namely, your budget, intended use, and driving style.

Most factory brake systems are designed for competent stopping when cold or hot, and quiet operation. In many cases, these components are not intended for severe use and repetitive stops with great kinetic energy. That doesn't mean you have to buy a six-piston-caliper setup with two-piece rotors. There's a good chance that a simple fluid, pad, lines, and rotor upgrade, like we performed on our '05 GTO, will bring your Pontiac into stop-on-a-dime territory.

Brake Rotors

The brake disc, or rotor, is the surface that is contacted by the pads. When the brakes are appled, abrasive friction is prevalent during lower temperature braking. It's simply the friction caused by the pads rubbing on the surface of the rotor. When temperatures rise, adherent friction comes into play, which is the process by which a thin layer of brake-pad material is transferred onto the rotor surface. This layer of pad material is what rubs on the brake pad.

Each type of friction allows for conversion of kinetic energy into thermal energy. Abrasive friction, as you may imagine, physically wear the rotors more quickly than adherent friction, but the latter will generally be tougher on the rotor thermally, which leads to heat cracking.

The metallurgy of the majority of rotors is comprised of several grades of cast iron. According to Emanuele Bruletti, Brembo's North American engineer, cast iron is a known metal with stable heat properties, and therefore a good candidate for rotors. The downside to the material is that it's very heavy, which has prompted manufacturers to make rotors out of lighter materials, such as lighter steel, aluminum, titanium, carbon/ceramic, and carbon/carbon. Even among the same materials, there are many rotor configurations available, either off-the-shelf or custom-tailored to your vehicle.

Vented Rotors And Cooling

Since the rotor receives the most thermal energy, or heat, it's very important to control this heat effectively. The use of vented rotors has become more common because the rotor itself features internal cooling passages that work like an impeller. When it spins, air is pulled through the "eye," or center, and is evacuated through the outside of the rotor. A downside to this is the resulting radiant heat-in other words, the rotor will actually heat everything surrounding it.

A vented rotor should be the only choice for a performance brake system, since a solid rotor must rely solely on ambient air to control temperature, while the vented rotor is continually moving air through it to better control heat. More air moving across the surface or through the rotor results in increased cooling ability.

Race cars and some street cars benefit from extensive use of brake-cooling ducts to draw cool air onto the rotor surface or rotor eye. This can lower temperatures as much as a few hundred degrees, allowing the brakes to perform better.

"When we set up a brake system for a customer on a race team, brake cooling ducts are fundamental," says Emanuele. "We ask them to focus on the cooling, because cooler rotors allow everything to perform better."

One-Piece Rotor

A one-piece rotor is cast with a hat-the area where the unit is mounted to the hub. Nearly all street cars come with these, and they're perfectly adequate for performance braking but may tend to warp due to thermal expansion. Here's why: When metal is heated, it grows. The diameter of a cast-iron rotor will grow as much as 2 mm, according to Stoptech. A one-piece rotor may be restrained from growing due to its design, which can cause the surface to misshape or warp. That's not to say that all one-piece rotors are the same. Many of the higher-end ones made by credible companies will feature a design less susceptible to this kind of distortion, making them just as effective at preventing it as a two-piece rotor.

Another downside to the one-piece design is weight. Since it's made of a single piece of like metal, there is no weight saved with the rotor hat. This shouldn't be a concern for cars that aren't going to see serious track time, where you are looking for the most intense performance and every last pound counts.

On the plus side, they're easy to manufacture and are off-the-shelf replacement parts. Many companies like Brembo, Stoptech, Wilwood, and Master Power Brakes make affordable replacement rotors for everything from modern Pontiacs to classics, providing excellent performance on a budget. Each has different features, from cross-drilling to slotted, and different ventilation designs.

Two-Piece/Floating Rotor

The two-piece rotor is the top choice of racers because of its better heat control and weight savings. These advantages are realized in two main ways, the first being the design.

Unlike the one-piece rotor with the hat cast into the rotor itself, two-piece rotors feature a separate hat. It's usually made from aluminum, and it allows the rotor to grow uniformly without distorting the friction surface, thereby reducing the likelihood of warping. An aluminum hat also transfers less heat from the friction surface to the bearings.

However, the top reason we find two-piece rotors on nearly all race cars is because they weigh less than one-piece units. Also of note is that the braking band is replaceable; when it wears out, you simple install a replacement.

On the downside, two-piece rotors are more expensive than one-piece. Though some companies may offer them as off-the-shelf parts ready for sale, sometimes they must be pieced together by finding the hat that works for your car and the proper braking band. For the serious racer, two-piece rotors are the best option.

Size And Weight

If thermal efficiency is so important, then when it comes to rotor size, bigger is better, right? Yes, but with some shades of gray.

A larger brake rotor has more surface area for the heat to spread across, making it more thermally efficient. This means that your brakes will perform better. The downside to the larger rotor is increased weight, caliper size, and the need for larger wheels. (You can only fit a certain size rotor behind your factory wheels.) Some companies offer low-profile calipers so you can run the largest rotor behind a smaller wheel, which is an excellent option for people looking to upgrade their brake system and retain factory-diameter wheels.

The increased mass is harder to stop, but since there are larger friction surfaces, bigger calipers and pads are used to exploit it. This unsprung weight-components not directly supported by the suspension-is also rotating. This is why two-piece rotors may be a good option, but weight reduction can be taken a step further.

Chevy's new Corvette ZR1 uses 15.5-inch, two-piece carbon/ceramic rotors made by Brembo. Carbon/ceramic material, or CCM, is a technology pioneered in Formula 1 racing with its carbon/carbon rotors. For the street, however, carbon/ceramic rotors perform better in a low-temperature range and provide excellent stopping, even when the brakes are cold.

CCM is absurdly light, approximately 50-percent lighter than cast iron. This reduction in unsprung weight translates into better overall braking, acceleration, and cornering performance. CCM rotors will retain their strength at 2,000 degrees Fahrenheit, while cast-iron liquifies at just over 2,100 degrees Fahrenheit.

The starting price point for a single CCM rotor can be as high as a complete big-brake system that uses more traditional two-piece cast-iron rotors. This is for two reasons. The exotic materials used in a CCM rotor take considerably longer to form; in addition, they are a "life-of-the-car" item that shouldn't have to be replaced.

Now that we've shown you why exotic materials are used in disc-brake designs, consider the main limitations on rotor size-budget and intended use. The bigger you go, the more expensive it's going to be, and don't forget the different wheels (and maybe tires) you will have to use. Just running a 14-inch rotor on a '02 Trans Am WS6 will require an 18-inch wheel in most cases. Keep these determinants in mind before selecting a rotor size.

Break-In

Rotors must be broken in properly. This procedure is called burnishing or bedding in.

Before using a new rotor, all machining and preservative oils must be completely removed following the manufacturer's recommendations. Usually it involves washing the rotors with soap and water or using one of the proprietary "brake-clean" compounds. Then mount the rotor and check it for run out.

It should be bedded in with a number of moderate/heavy stops, followed by a lot of cooling time between stops, gradually increasing the severity of the stops until the entire surface of the rotor is evenly discolored. This will prevent thermal shock, distortion, and the formation of "hot spots," regional deposits of pad material, which results in a permanent transformation of the cast iron underneath the deposit.

According to Brembo, once a rotor develops a hot spot, it must be replaced. Many automotive brake shops will "turn" or "cut" the rotor, but this is not a solution and it will only lead to the same problem.

Conclusion

Now that you're familiar with brake rotors and their different designs, you can make a fair judgment on which ones are right for your car. There are plenty of sizes, configurations, and materials to choose from, whether you want your Pontiac to perform better or just stand out.

In our next installment we will discuss brake pad friction materials, calipers, and fluids.

Cross-Drilled Versus Slotted

Once you've chosen the rotor design that is best for your application, it's time to add the bells and whistles, i.e., cross-drilling and slotting. The debate over which configuration is preferred has been going on for quite some time because there are stories of cross-drilled discs cracking, slotted discs eating up pads, and solid discs being the best overall.

What's true? We sat down with Brembo North America's chief engineer, Emanuele Bruletti, and High-Performance director, Adrian Smith, and asked them which disc design is the best.

HPP:There's been a lot of uncertainty surrounding cross-drilled and slotted rotors. People complain that cross-drilled rotors will crack under heavy use, yet some race cars still use them. I've heard that cross-drilling only benefits certain pad materials. How true is any of this?

Emanuele:Well, that is certainly a big question because not everyone agrees. From what we have found, yes, it is true that cross-drilling creates stress points for a crack to form, but that doesn't mean they're bad. Cross-drilling can help the rotor cool because it increases the surface area for the heat to dissipate.

It also wipes the pad surface clean, which helps with initial bite. Racers all want a confident brake system-something that bites right when they hit the pedal every time. Cross-drilling helps with this, and racers view rotors as disposable items and usually replace them after every race. So if cracks do form, they aren't on the rotor long enough to degrade the rotor's quality.

Adrian:That's why most racers just run a slotted rotor. A slotted rotor wipes the pad surface clean in the same way, so you get that instant bite that drivers are looking for without the enhanced risk of cracking. Cross-drilling is mainly a cosmetic feature because it has long been associated with performance brakes, but most racers have moved away from it.

HPP:So is it true that cross-drilling can cause the rotor to crack?

Emanuele:It certainly enhances the sensitivity for cracks to form, but if the rotor was designed to have cross-drilling, they can prove to be very strong and resilient. The owners should enjoy only the good attributes that go along with cross-drilling. Many of the cheaper bargain cross-drilled rotors are to be avoided.

HPP:Should someone looking for performance choose slotted rotors over cross-drilled?

Emanuele:It's a personal choice, but yes, I would say so. OEMs still use cross-drilled rotors on Ferrari, Corvette, and Porsche without the configuration becoming a major problem. Still, it's not as prevalent as one would assume, especially in street use. You will find that most race teams and hardcore track guys run only slotted rotors; only a few use a cross-drilled rotor.

HPP:What about "drilled and slotted" rotors? They have become more common for aftermarket add-ons.

Adrian:We only offer cross-drilled or slotted, but not both together. It's a bit redundant. The cosmetic value is rather high though.

After talking with Emanuele and Adrian, I was able to determine that while the rumors may have some truth to them, it comes down to personal preference and the intended use. However, cheap off-brand rotors should be avoided all together.

How To Choose the Right Brake Rotor?

What is a Brake Rotor?

Brake rotors are an important component in the braking system that stops your vehicle. It is a flat, circular metal disc that is mounted on the wheel hub. Vehicle’s brake pads clamp down onto the brake rotors, creating friction, which slows down the rotation of the wheel and ultimately brings the vehicle to a stop.

Over time, brake rotors can wear down due to the constant friction and heat generated during braking. If a rotor becomes too worn, it may develop grooves, cracks, or other defects that can compromise its effectiveness and safety. In such cases, it’s important to have the rotors inspected and, if necessary, replaced by a qualified mechanic.

Replacing the warped or damaged brake rotors is vital, not just for you, but also for the safety of the passenger and the world on the roads.

There are several different types of brake rotors available. If you are having trouble deciding which one to choose? We are here to help. You will be able to determine which are best suited for your car or truck, and how you can maintain them. 

1. How to choose the Right Brake Rotor?

2. What are different Types Of Brake Discs?

• Solid Disc Brakes
• Vented Disc Brakes

3. What material are Brake Rotors Made Of?

• Cast Iron Brake Rotors
• Steel Brake Rotors
• Layered Steel Brake Rotors
• Aluminum Brake Rotors
• High Carbon Brake Rotors
• Ceramic Brake Rotors

4. Which brake rotor is better, Smooth, Cross-drilled, Slotted or Drilled and Slotted?

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• Blank or Smooth Brake Rotors
• Cross-Drilled Rotors
• Slotted Rotors
• Drilled and Slotted Rotors

5. How Do You Know It’s Time To Change The Worn-Out Disc Brake Rotors?

6. Can You Replace Solid Rotors with Vented Rotors?

7. Why Upgrade to New Rotors?

8. What Kind of Rotors Do I Need? 

9.What are essential Brake Rotors Buying Tips?

10. What is the Cost Of Brake Rotors?

11. The Best Brake Rotor Brands Which brake rotor to buy?

• Raybestos Brake Rotors
• Worldparts Brake Rotors
• Transit Warehouse Brake Rotors
• RS Parts Disc Brake Rotors

1. How to choose the Right Brake Rotor?

Selecting the right brake rotor is essential for ensuring the safety and performance of your vehicle’s braking system. Here are few simple things to keep in mind:- 

Make and Model of Vehicle – Ensure that the rotor you choose is compatible with your vehicle’s make and model, as different vehicles may have specific requirements 

Material – Brake rotors are typically made of cast iron, composite, or carbon ceramic. Cast iron rotors are the most commonly used for everyday driving. Composite and carbon ceramic rotors offer higher performance but are expensive. 

Rotor Design – There are various rotor designs, including standard, drilled, and slotted. 

    –  Standard rotors are solid discs and are suitable for regular driving conditions.

    –  Drilled rotors have holes drilled into them to dissipate heat more effectively, making them ideal for high – performance applications.

    –  Slotted rotors have slots carved into the surface, improving brake bite and aiding in heat dissipation.

Driving Conditions – For everyday commuting, standard rotors may suffice. High – performance options like drilled or slotted rotors might be more suitable for track events

Budget – High performance rotors which offer better performance come with a higher price tag. Consider the budget and balance it with your requirements.

Brake Pad Compatibility – Ensure that the brake rotor you choose is compatible with the type of brake pads you intend to use. 

Brand and Quality – Choose reputable brands which offer high quality brake components. As they have better quality control and materials.

Warranty – Brake rotor that comes with a warranty can provide you with assurance about the quality and durability of the product.

Reviews and Recommendations – Look for customer reviews and seek recommendations from trusted sources, such as mechanics, automotive enthusiasts or PartsAvatar blog. 

Always remember to consult your vehicle’s manual or seek advice from a qualified mechanic if you’re unsure about which brake rotor is best suited for your vehicle and driving needs.

2. What are different Types of Brake Discs?

The disc brake system relies heavily on the brake rotors, constituting half of its friction components. These rotors are typically circular metal surfaces crafted from cast iron and are positioned directly behind the rim with calipers facing either the front or rear. Brake discs can come in two variations: flat discs and vented discs. Let’s examine these types more closely.

Solid Disc Brakes

Vented Disc Brakes

3. What material are Brake Rotors Made Of?

Cast Iron Brake Rotors

Steel Brake Rotors

Layered Steel Brake Rotors

Layered Steel Brake Rotors involve laminating sheets of steel together, providing durability and resistance to warping. They are long-lasting in nature, requiring less frequent repairs or replacements.

Aluminum Brake Rotors

High Carbon Brake Rotors

Ceramic Brake Rotors

4. Which brake rotor is better, Smooth or Cross-drilled or Slotted or Drilled and Slotted?

Blank or Smooth Brake Rotors

Blank or smooth brake rotors, commonly found in factory-equipped vehicles, provide a seamless friction surface for brake pads to engage. This setup generates the necessary friction to slow down your vehicle. Opting for smooth rotors is a popular choice due to their affordability, cost-effective manufacturing, and reliable braking performance over extended use.

Pros: –

• Cost-effective option.
• Reduced likelihood of crack development due to absence of drill holes or slots.
• Suitable for vehicles not subjected to extreme or aggressive driving conditions.

Cons:-

• Slower heat dissipation, potentially leading to faster brake pad wear.

Cross-Drilled Rotors:- 

These rotors feature drilled holes for rapid heat dissipation, ensuring extended braking performance and minimizing brake fade during heavy use. Additionally, they aid in swift water dispersal in wet conditions, preserving initial braking efficiency. Ideal for all-weather performance upgrades, especially for car enthusiasts.

Pros:- 

• Effective in hilly areas, allowing for quick water drainage.
• Reduced water presence enhances brake performance.
• Assists in rotor cooling.

Cons:- 

• Aged rotors may exhibit worn drill patterns, impacting vehicle aesthetics.
• Not recommended for racing vehicles due to faster wear and potential cracking.
• Prone to earlier failure due to repeated heat and cool cycles.

Slotted Rotors:- 

These rotors feature thin slots or lines on the surface, akin to cross-drilled rotors. They enhance cooling and water dispersion. Unlike cross-drilled rotors, slotted ones prevent clogging from mud and debris, making them ideal for trucks and off-road vehicles. Additionally, they allow gases generated by excessive heat to escape, reducing brake fade.

Pros:- 

• Ensures consistent stopping power and reduces brake pad friction.
• Well-suited for heavy trucks, SUVs, off-road, and tow vehicles.
• Effectively removes glaze from overheated brake pads, improving braking.

Cons:- 

• Outer edges may crack if not machined properly.
• Shorter lifespan compared to other rotors, potentially affecting brake pad longevity.

Drilled and Slotted Rotors: – 

Combine advantages of both drilled and slotted types. Ideal for performance-oriented drivers seeking top-notch performance. Features include quick response in various conditions, rapid heat dissipation, reduced brake fade, and extended lifespan. They are a premium, albeit costly, option.

Pros:- 

• Excellent for wet climates with frequent rain.
• Ideal for carrying heavy loads.
• Exceptional for providing the necessary stopping power in heavy vehicles.

Cons:- 

• Not recommended for racing due to potential for cracking.
• Cannot be resurfaced; replacement is required if damaged.

5. How Do You Know It’s Time to Change the Worn-Out Disc Brake Rotors?

Here are the signs which tells us that it’s time to change worn-out disc brake rotors: – 

Squealing Noise While Braking – This indicates potential issues with brake pads, improper installation, or warped and damaged rotors. Worn-out rotors can accelerate brake pad wear.

Vibrations – Heavy vibrations during braking may signify rotor damage or warping, ranging from minor surface marks to significant grooves from prolonged contact with thinning rotors.

Longer Stopping Time – If brakes take longer to stop, it can pose safety risks. This could be due to brake line complications, damaged calipers, or leaky brake fluids. Consult a professional mechanic.

Warning Light – Some cars feature a dashboard warning light for brake maintenance. Note that these sensors usually have a similar lifespan to brake pads and should be replaced simultaneously.Car Pulling to One Side – A vehicle veering to one side while driving may indicate worn-out brake pads or sticking caliper guide pins or pistons.

6. Can You Replace Solid Rotors with Vented Rotors?

Yes, it is possible to replace solid rotors with vented rotors. But it is important to keep following points in keep in mind:

Compatibility – Ensure that the vented rotors you intend to use are compatible with your specific make and model of vehicle.

Caliper Compatibility – Check if the calipers on your vehicle are designed to work with vented rotors. Vented rotors are typically thicker, and they may require calipers with larger pistons.

Brake Pad Compatibility – Verify that the brake pads you plan to use are compatible with vented rotors. Some rotors may require specific types of brake pads for optimal performance.

Brake Bias – Switching to vented rotors may affect the brake bias of your vehicle. This could potentially impact the balance between front and rear braking. It’s important to ensure that the overall braking system remains balanced and effective.

Wheel Clearance – Vented rotors are thicker than solid rotors. Confirm that there is enough clearance within your wheel assembly to accommodate the larger size.

Professional Installation – It’s recommended to have a qualified mechanic perform the installation to ensure it’s done correctly and safely

7. Why Upgrade to New Rotors?

Upgrading brake rotors offers improved performance and increased vehicle safety. Benefits include: –

Enhanced Braking Performance – Worn-out brake rotors can lead to longer stopping distances. Upgrading to top-rated disc brakes reduces brake fade and shortens braking distance.

Smoother Braking – Disc brakes provide a more responsive and less spongy brake pedal feel, with reduced vibration during braking.

Improved Wet Weather Performance – Premium disc brake rotors like cross-drilled or drilled and slotted types enhance braking in wet conditions by allowing water to escape quickly.

Extended Lifespan – Upgrading both brake pads and rotors simultaneously improves braking performance and increases their overall lifespan, ensuring maximum mileage.

8. What Kind of Rotors Do I Need?

Choosing vented disc brakes is a better decision, as they offer benefits in terms of both weight and performance. Vented rotors are notably lighter than their solid counterparts, thanks to the presence of strategically placed vents. These vents also play a crucial role in dissipating heat, significantly reducing the risk of brake fade. Consequently, vented brake discs exhibit prolonged performance and superior airflow compared to solid ones. However, it’s worth noting that these advantages do come at a premium price point, whereas solid rotors, being more budget-friendly, remain a popular and practical choice.

9. What are essential Brake Rotors Buying Tips?

Trusted Name – The brakes are an important component of your vehicle. So do not seek a big bargain on any of the brake parts. 

Choose Carbon-Ceramic Composite – This material is usually costly and if you can afford them, then just go for it. If a component has a higher carbon content, then it has a longer lifespan and offers better braking performance.

Close Attention To Warranties – Pay close attention to warranties for disc brake rotors, as they are limited and specific. Replacements are available only if there are any defects. Only a few high-performance brake companies provide lifetime warranty where the parts will be costly. So you will have to decide and balance between price and warranty.

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