Want to know if drilled and slotted rotors are what you need?
Drilled and slotted rotors are brake rotors with holes and slots in them. They evacuate the moisture and brake dust generated during braking, cool down your brake disc, and increase contact friction for superior brake performance.
Still a bit confused?
Just stick around!
This Article Contains
- What Is a Drilled and Slotted Rotor?
- Why Use Drilled and Slotted Brake Rotors?
- What Are the Limitations of Using Slotted and Drilled Rotors?
- What Are the Symptoms of Failing Drilled and Slotted Rotors?
- How Much Does a Brake Rotor Replacement Cost?
Let’s get started.
What Is a Drilled and Slotted Rotor?
A drilled and slotted rotor is a type of brake rotor (disc brake) with a series of drilled holes and curved grooves machined across its surface.
What is a brake rotor?
Essentially, when you hit the brakes, brake calipers near the wheels compress your brake pads (which could be ceramic pads or metallic brake pads) against your brake disc to generate friction. This friction force helps slow down the car and bring it to a halt.
What Are the Different Kinds of Rotors?
Besides the slotted and drilled rotors, you also have the:
- Plain rotor: a smooth rotor with a plain surface and no holes or grooves in it (also called standard rotors)
- Drilled rotor: a solid rotor with a series of holes drilled into the rotor surface (a.k.a. cross drilled rotor)
- Slotted rotor: a solid rotor with grooves or lines machined along its surface
- Vented rotor: a brake rotor with two discs (inner and outer) connected by ribs
Drilled and slotted brake rotors are popular for high performance and heavy-duty vehicles like tow trucks, motorsport cars, etc. These performance brake rotors offer improved stopping power and help you combat brake fade.
Note: Brake fade is the gradual decrease in stopping power of your braking system due to prolonged use and frequent braking.
Why Use Drilled and Slotted Brake Rotors?
Here are some reasons why you should consider using slotted and drilled brake rotors for your car:
1. Enhanced Brake Grip
Slotted and drilled discs offer enhanced brake grip for more efficient brake performance.
When you’re braking, the kinetic energy of your vehicle becomes heat because of all the friction between the pads and brake discs. As a result, repeated braking leads to higher temperature rises.
At elevated temperatures, the resins in your brake pad material can burn up, producing gasses that ultimately compromise your braking performance. Fortunately, the disc brakes’ drilled holes can quickly expel these offset gasses to restore braking grip rapidly.
2. Heavy-Duty Brake Support
Heavy-duty and high performance vehicles like trucks require extra braking support from performance brake rotors.
Heavy vehicles need more stopping power to slow down. Slotted and drilled discs have a comparatively lighter mass than blank rotors, which helps slightly reduce the vehicle’s inertia. That’s why drilled and slotted rotors are excellent at delivering that powerful yet smooth braking performance to bring your heavy-duty vehicle to a stop.
3. Wet Climate Suitability
When you’re driving in wet climates, the profile of your braking system changes.
Moisture between your brake pad surface and brake disc can reduce the amount of friction your braking system generates. This leads to lower stopping performance for your cars.
The drilled hole and slot pattern in your disc brake allows the moisture and brake dust to escape. This keeps your disc brakes dry, helping you achieve consistent braking performance even in wet weather conditions.
4. Faster Cooling Rate
When braking, the point of contact between your brake pads and rotors heats up due to friction. Frequent heavy braking can lead to higher temperature build-up, which causes the pads to fade, crack, and develop other problems in the long run.
Now, your car needs sufficient airflow to keep the brakes cool. But, standard rotors take longer to cool down compared to slotted and drilled rotors. Each drilled hole and slot on a slotted and cross drilled rotor increases the rotor’s surface area. This allows heat to dissipate faster, cooling down the brake system at a higher rate.
5. Slows Down Brake Pad Glazing
If you’re going down a hill or stuck in traffic, you’ll likely apply brakes more frequently.
Doing so can increase the temperature of your brake system, causing your brake pad surface to smoothen and harden (known as glazing). Over time, the pads’ surface starts to mirror the disc brake, and they become incapable of generating sufficient friction.
Fortunately, in drilled and slotted brake rotors, the grooves on your rotor chip off the pad material to slow down glazing.
Now, let’s also look at some disadvantages of using drilled and slotted rotors.
What Are the Limitations of Using Slotted and Drilled Rotors?
Although drilled and slotted brake rotors offer many advantages over factory rotors (smooth rotor), they have some downsides.
1. Premature Brake Rotor Wear
Sometimes, your drilled and slotted disc brakes tend to wear out prematurely. It usually happens when the same areas of your slotted brake rotors are in contact while braking, resulting in uneven wearing.
This is more common if you use them in a high performance vehicle. The high temperature and repeated stress can cause them to develop cracks and wear down over time.
2. Short Rotor Lifespan
Generally, cross drilled rotors and slotted discs have a shorter lifespan compared to blank rotors.
So, if you encounter harsh driving conditions regularly and are likely to engage in heavy braking, your drilled and slotted brake rotors will wear out even quicker. They might also need replacing as often as your brake pad set.
On average, you can expect to replace your slotted and drilled rotors between 25,000 to 35,000 miles.
3. Steering Wheel Vibrations
Your drilled and slotted disc tends to wear out in concentric circles. When that happens, its hole pattern gets disrupted, causing vibrations on your steering wheel.
4. Can’t Resurface Rotors
A significant disadvantage with drilled and slotted rotors over a plain rotor is that you can’t resurface them. If these specialized rotors are distorted or damaged, they can significantly affect your brake performance.
The only solution is to replace your stock rotor (OEM rotors), and replacing a stock rotor is usually more expensive than resurfacing one.
Since you’ve got an idea of the problems faced with a drilled and slotted brake rotor, let’s check out the signs of a faulty brake disc.
What Are the Symptoms of Failing Drilled and Slotted Rotors?
A drilled and slotted brake rotor affects how much braking power your car generates. So driving around with a defective drilled and slotted disc can be a significant safety hazard.
If you notice any of the symptoms below, consider getting your drilled and slotted disc inspected and replaced by a mechanic.
1. Squealing Noise When Applying Brakes
If you’re hearing high-pitched squealing or squeaking noises when braking, chances are your drilled and slotted brake rotors are badly worn out or warping. If you’ve got extensively warped rotors, you’ll likely hear scraping sounds.
When this happens, take your car to an auto repair shop, or have a mechanic come over and inspect your rotor surface and other brake kit parts (such as the brake pads, brake calipers, brake fluid lines, etc.) to identify the underlying issues.
2. Excessive Brake Vibration
If you can feel irregular vibrations on your brake pedal or through the vehicle chassis, it could signal damaged slotted and drilled brake rotors.
Warping rotors tend to cause brake pulsation that ripples through your car.
3. Grooves on the Brake Rotor
This isn’t something you can readily notice. However, if you do manage to see unusual grooves or scoring marks on the rotor surface, your brake disc will face imminent failure.
These marks, developed over time from repeated contact with the brake pads, can significantly weaken your brake system and cause brake pulsation on the brake pedal when braking. In such a scenario, request a brake system inspection and ensure your mechanic uses quality replacement brake parts like authentic OEM or factory rotors.
How Much Does a Brake Rotor Replacement Cost?
The cost of replacing your disc brake depends on the vehicle model and make. You can expect to pay between $230 and $500 for a disc brake replacement.
Note: Aftermarket slot and cross drilled rotors from brands like Power Slot and Stoptech can cost around $120 to $500.
Slotted and drilled discs effectively enhance brake grip, combat brake fade, and help you drive in wet weather conditions. However, because of their shortcomings, you’ll need to ensure that your performance rotor stays in check.
If you notice any symptoms indicating brake disc damage, consider having your drilled and slotted brake rotors inspected and replaced ASAP. And if you want to get your brake rotor repairs done right in your driveway, the easiest way is to get in touch with AutoNation Mobile Service!
AutoNation Mobile Service has expert mobile technicians on standby seven days a week, and all repairs on defective drilled and slotted brake rotors come with a 12-month/ 12,000-mile warranty.