A smooth brake rotor that's worn and ready for replacement.

Brake Rotor Replacement: Slotted, Smooth or Cross-Drilled?

When considering brake rotor replacement, you may be tempted by several of the options that are presented to you to enhance your vehicle’s stopping power. In fact, there’s a small universe of bolt-on brake parts out there that are intended to upgrade your stock components without asking you to make any modifications to your vehicle, and rotors are no exception.

Which brake rotors should you consider for your vehicle? Check out our breakdown of the three most common types of rotors you’ll find when it comes time to replace your worn-out set.

1. Slotted Rotors

Slotted brake rotors get their name from the channels, or slots, that are machined into the surface of the disc. Typically, these brake rotor replacement parts feature angled slots that arc out from the center, or sometimes radiate in a in an S-groove pattern.

The concept behind a slotted design is to provide an escape channel for the gas and dust that’s produced by your brake pads when pressed against the rotor. Instead of building up on the surface, these elements escape through the slots, reducing temperature thereby improving stopping performance by allowing the pad to make more direct contact with the disc.

One down side of slotted rotors is that the edges of the slots scrape against your brake pads, which may require more frequent replacement intervals.

2. Cross-Drilled Rotors

Cross-drilled brake rotors

Cross-drilled rotors take a different approach to venting gas and heat by way of the holes that pass directly through the entire disc. These are geared more for high-performance and track driven vehicles where braking effectiveness is more important than longevity. A shortfall of this design is the holes can actually weaken the disc and can cause cracks to occur under extreme braking, similar to what you would encounter in a high-performance driving situation.

You can go all the way and purchase brake rotor replacement parts that are both slotted and cross-drilled, but you may not be happy living with the after effects on a daily driver street car.

3. Turned or Non-Directional Rotors

Turned or non-directional rotors — also known as stock replacements — offer none of the trade-offs of cross-drilled or slotted designs. Strong, durable and able to offer their complete surface to a brake pad, turned or non-directional rotors are often the best all-around choice even for everyday drivers and those looking for improved performance and pedal feel. 

Slotted and cross-drilled rotors are certainly stylish, but smooth is often the best way to go when sourcing brake rotor replacement parts. A reality check about the type of driving you are most likely to do with your vehicle will help you make the best decision for your needs.

Check out all the brake system products available on NAPA Online or trust one of our 16,000 NAPA AutoCare locations for routine maintenance and repairs. For more information on brake rotor replacement, chat with a knowledgeable expert at your local NAPA AUTO PARTS store.

Photo courtesy of Flickr.

about author

Benjamin Hunting

Having been bitten by the car bug at a young age, I spent my formative years surrounded by Studebakers at car shows across Quebec and the northeastern United States. Over ten years of racing, restoring, and obsessing over automobiles lead me to balance science writing and automotive journalism full time.  I currently contribute as an editor to several online and print automotive publications, and I also write and consult for the pharmaceutical and medical device industry.

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