10 Drilled and Slotted Rotors Pros and Cons

There are several different types of rotors available for vehicles today: blanks, drilled, slotted, or drilled and slotted.

Rotors, which are sometimes called discs, provide a point of contact for your brake pads when you engage the pedal to stop while driving. The pressure from the pedal activates the caliper housing for each set of pads, compressing them into the rotor to create friction. That set of processes reduces the forward momentum of the vehicle, which allows you to come to a complete stop whenever necessary.

The design of drilled and slotted rotors offer drivers the advantages of both designs with minimal side effects. The drilled holes give you better cooling for the heat generated by heavy braking, while the slots work to sweep away gas and dust which come through braking. That also means the disadvantages of both drilled and slotted rotors apply to this product.

If you’re thinking about a disc replacement today, then here are the pros and cons of drilled and slotted rotors to think about.

List of the Pros of Drilled and Slotted Rotors

1. They work better in wet climates when frequent precipitation occurs.
When the weather turns wet, does the braking profile of your vehicle change? If it does, then there’s a good chance that you’re using blanks or slotted rotors on your vehicle. Drilling holes in the rotor give the pads a better bite when you engage the braking system. More friction develops when the system engages because the holes offer moisture a place for escape. Even when water is present, the components of your system stay drier, which means your performance is enhanced.

2. They provide support for heavy-duty vehicles.
The slots on rotors provide extra support for all heavy-duty vehicles, including off-road, competition, and trucks. When choosing rotors with slots, the quality of the machining becomes the most crucial attribute for success. The inner and outer edges must be crafted with an excellent skill to prevent them from cracking sooner than they should. That means you can choose almost any drilled and slotted rotor design for any vehicle you own if you trust the manufacturing process of your preferred brand.

3. They can stop brake pads from glazing.
Brake pads can glaze when there is a continuous application of braking, like when you’re going down a mountain descent. The constant application of friction between the pad and rotor causes surface glazing. Light application of braking functions most of the time can cause some pads to polish themselves too. Reducing braking performance occurs during this situation, including the squealing associated with excessive pad wear.

The drilled and slotted rotor design helps some pads disengage from the glazing process. When constant friction is present within the driving environment, the pad fuses part of itself to the disc, causing the lack of performance, The slots on a rotor break up the contact points of the pad, providing vital momentary pauses in contact that stop the process from occurring.

4. They offer daily driving support.
When you’re behind the wheel every day to commute back-and-forth to work, you want two things from your braking system: a solid bite and consistent friction. That promotes robust stopping power when you need it during an uncertain situation. Drilled and slotted rotors offer drivers the consistent performance they want without changing the responsiveness of the brake pedal. This process gives you the confidence needed as a driver that you can handle whatever situation might come your way.

List of the Cons of Drilled and Slotted Rotors

1. They sometimes experience premature wear.
There are several advantages to consider with drilled and slotted rotors, but it comes with the same disadvantages for each style too. That means your rotors will sometimes wear unevenly when using your brakes if the same area of the rotor receives contacts. High-performance vehicles see this issue most often, with cracks sometimes developing due to the heat and extreme environment they encounter. If you use a vehicle for frequent stops at highway speeds, you may encounter this issue too.

2. They tend to wear in grooved cycles.
Drilled and slotted rotors tend to wear down in concentric cycles, which means you can receive vibration in the steering wheel over time when the rotors age or the hole patterns are not staggered correctly. This issue may cause some vehicle owners to swap out their rotors more often because of the aesthetic concerns they cause. If you’re sensitive to this issue, then a rotor designed more for your specific environment will meet the demands of how you drive each day.

3. They have a shorter lifespan.
Slotted rotors already have a shorter lifespan compared to other options for your vehicles. They also cause some brake pads to experience higher levels of wear-and-tear too. If you drive regularly and go through a period of heavy braking, you may discover that the drilled and slotted rotors require replacement about the same time as your brake pads. Depending on the quality of the rotors used, that means you could be replacing these items as soon as every 25,000 miles – and even more often for frequent city drivers.

If you’re looking for extended life with your brake rotors, then your best option will always be the blank design. It offers more metal for contact, providing a consistent surface of impact to create friction for your stopping power.

4. They sometimes create extra noise when stopping.
All brakes create a squealing sound when the pads wear down because you have metal-on-metal contact. The issue with drilled and slotted rotors involves the rumbling that you hear because of the slot engagement with the pads as you stop. This issue doesn’t impact the safety of your braking system. Some drivers find the extra noise to be more than a little unpleasant. Heavy vehicles can create an excessive sound level which isn’t dampened when the windows are rolled up.

5. They don’t offer a cooling effect for all vehicles.
Drilling does help a rotor cool down some for all vehicles because there is less metal involved with the contact points from the pads. That can be beneficial for some vehicles, but it does create a negligible effect in others. The opposite effect impacts the rotors too. Because there is less metal involved with the design, the disc heats up faster than a solid rotor would. That’s why you don’t use this design in high-performance settings. Too much heat causes warping or cracking, which requires you to complete an immediate repair.

6. They cannot be resurfaced.
If something happens to your drilled and slotted rotors for some reason, then a full replacement is necessary. You cannot resurface the rotor to restore its functionality as you can with some solid-type discs. Although the cost difference of resurfacing is somewhat minor compared to the cost of a full replacement, those who prefer a DIY approach to swapping out the brakes will discover that this disadvantage might cost them a couple hundred dollars, if not more, to complete the necessary work.

These drilled and slotted rotors pros and cons look at the details of using this design with your current driving habits. Most street vehicles benefit from this design, especially in wet environments, because of the consistency offered. There are exceptions to this based on how you use your car, however, so review each point carefully to ensure this investment makes sense for your current needs.

About the Author
Brandon Miller has a B.A. from the University of Texas at Austin. He is a seasoned writer who has written over one hundred articles, which have been read by over 500,000 people. If you have any comments or concerns about this blog post, then please contact the Green Garage team here.