Drilled, Slotted & Vented Brake Rotors - What's Best?

When replacing your brake rotors, you may opt to upgrade to drilled, slotted, or vented rotors. Which brake rotor is best? What brake rotors will perform better? What are the best options for performance brakes? Ultimately, vented disc are great for heat rejection. Slotted rotors can aid in moving debris away from the rotor, and potentially adding a biting surface for the pad to contact. Drilled rotors aren't used in professional racing due to the stress failures they tend to have.

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[chazwazzum]

I put drilled-slotted-vented-carbon rotors on my Prius and now it stops so hard my wife's dentures fly out every time.

[ZepG]

The drilled rotors not only look cool but according to ricers add 20 hp.

[MickaelMaddison]

On my minivans I switched to drilled and slotted discs as a method of cooling the disks faster. The stock discs were continually warping because of the long steep hills near my home. Switching has proven to be very effective as my discs have not warped for years since the switch. I go through pads more frequently but they are cheaper and easy to replace.

[manekineko]

There are functional advantages to using drilled rotors. Why this is so is a little complicated, and takes a few paragraphs to explain. (see below). That there are advantages is well established, and this is mostly their ability to bring a high performance pad up to peak temperature very rapidly. This is useful on lighter weight, performance oriented street cars and some forms of racing where the brake loads are intermittent.

Drilled rotors are used on the street versions of high-performance cars which will never see any serious track time, but which may be driven quite vigorously from time to time. Sprint car racers also prefer them. All of this general group of performance cars driven mostly on the street [e.g. Lotus Elise, or Porsche Cayman] have brake pads with friction coefficients that increase as temperatures go up. These pads need to be warm to have the optimum response, and improved feel, during braking.

Brake pads do not conduct heat well. Some have copper threads added to improve conduction, but basically a pad does not conduct much heat. The primary path for heat conduction out of the pad, is into the rotor. When a rotor is drilled or slotted the area for heat transfer out of the pad is reduced, and so the pad rises to 'operating temperature' much more quickly the same pad will come to temperature with a plain surfaced rotor.

For a car equipped with higher temperature pads that is not driven on a circuit track, drilling or slotting the disk, reduces heat transfer out of the pads, bringing the brakes into their optimum working temperature immediately, the first time they are applied. There is no need for this rapid warm up on a car driven on a long circuit track, where the brakes are brought to temperature in the first turn and remain hot throughout the race.

There are forms of racing in which drilled rotors are very much preferred. Drag racing is an obvious application. In this form of racing the brake pad must be brought to temperature very quickly and their brake disks are perforated to the point of looking like lace. Lighter weight open wheel cars like Sprint racers prefer drilled and/or perforated rotors, because braking loads are moderate, and the cooling of the disk itself is very rapid. Many 'sport' motor cycles use drilled rotors for this reason as well. These are all applications where drilled rotors are used for functional reasons.

Drilled rotors, unlike slotted rotors, pump air through the holes as the leading edge of the brake pad approaches the hole. In a centrally vented rotor, the vanes in the center vent draw air from the holes and sling it outward in a continuous cooling loop. So drilled and perforated rotors have the advantage that while the pad heats more quickly, and the rotors themselves, having less mass may also spike in temperature, they also lose that heat very rapidly. For intermittent braking this is an advantage. For circuit racing drilled and slotted disks are generally a disadvantage. For rally cars, slotted are often preferred. Pad wear is greater, but so the braking, and that is to be expected.

While the adhesives in brake pads no longer off-gas as badly as they once did, this is not the only source of gas between the pad and the rotor. Steam can be a serious problem in the initial applications of wet disk brakes. While driving in rain, drilled rotors provide an exit path for steam in a way other rotors do not. So there are all sorts of applications in which perforated rotors excel. And these applications have nothing to do with appearance. The limitation for drilled rotors is the potential for cracking. Cracking around the outermost holes can occur either when the rotor is used above its temperature range or when the quality of the casting is poor.

There is no down side to using a drilled rotor in applications in which the heavy loads are intermittent, and there are many advantages, especially for lower power and lighter weight performance oriented cars.

[superhydrocarbon]

Man, your videos are simply fantastic! Such high quality content and they make perfect sense! Amongst the best channels on YouTube!

[racekar]

I have to comment, I have a Porsche 997 Carrera that I track, I am a DE instructor with many years experience. My car came with drilled rotors and I added track pads, car stopped very well. Unfortunately as you stated the rotors eventually cracked between the holes. I switched to slotted rotors and immediately noticed a reduction in braking force. After many sets I went back to drilled rotors and the braking is much better. Just a personal observation, Porsche knows why the holes are there, it's not just looks.

[Smart-Skippy]

I have a 25 year old E36 Bimmer and now run Drilled Vented Slotted front discs and Drilled Slotted rear discs both with ATE Low dust pads. Effing amazing stopping power. I'm in Perth Australia and it is very seasonal rain wise. Simply little chance of warping or cracking due to splashing hot discs. I suffer almost no fade even after a 3 am fast run across the city.
For me, matched to Bilstein Shocks and up-rated roll bars, polyurethane bushes and a very worked engine I adore my car.
Oh and I'm 52... not a kid.

[ZepG]

Thanks for the video, after watching this the first time I was in a mild fender bender in my SVT Focus in the rain. I had been driving for awhile without using my brakes when all of a sudden traffic stopped and I mashed the pedal to the floor, my car braked very slowly with no skidding or anti-lock and tapped the rear bumper of a Prius. After the accident I tested my brakes in the rain and realized that the first strong application was slow to stop but the next two got better and my anti-locks kicked in. My feeling was that the layer of water between the discs and pads hindered my initial braking effort.

I remembered your video and avoided buying the drilled and slotted rotors and instead ordered EBC slotted rotors knowing that the pads might wear out faster but the extra biting edge and hopefully some water evacuation would be an improvement, thanks for steering me away from the drilled weaker rotors and keep up on the good informative videos!

[Myles]

Nice, objective and un-sponsored truth.

[colinhare]

After watching videos for a while, I find your teaching method superb: You have the board you read off of which sums up what you're saying, but then elaborate off of that much more vocally, which is super useful for getting the gist and more.

[theprofessional]

To everyone, remember this, TORQUE YOUR LUGNUTS, reduces warping.

[dreflow]

I run drilled and slotted on 98 expedition. started pulling a 6x12 open trailer with a riding lawn mower occasionally and immediately noticed that the truck didn't stop well with the extra weight. Purchased the drilled and slotted rotors and it's a world of difference. by the way if anyone is wondering about how I drive, I am a 23 year veteran truck driver with no accidents . All I'm saying is when I know what works for me, it's kind of hard for me to take advice from anyone who says otherwise.

[Tropicsca]

i've been researching brakes for months trying to figure out what actually works and if you actually get the performance you pay for. This video helps so much! Once again, you're the only person that makes videos that are completely blunt and direct so we can all understand in laymans terms. 
*I am going to choose the slotted rotors simply because i change my brake pads yearly anyways, so i'm not concerned with premature pad wear. But i DO want more brake bite. Thanks!

[neonskyofficla]

It's pretty cool how I needed brake advice and immediately searched "engineering explained brake rotors" and this video popped up with the exact unbiased science behind it that I was looking for. Thanks!

[joscythe]

I'd be intersted in a video about "brembo style" brake calipers (4 pot, 6 pot, 8 pot...) compared to conventional style brake calipers

[The_R-n-I_Guy]

I drive a 96 Buick Roadmaster. It's very heavy. I put drilled and slotted rotors on the front. Since then I've noticed that I can stop a lot faster. They might not be the best for racing, and might wear the pads faster, but for my heavy car and lead foot, I love them

[Squat]

My personal favorite is vented/ slotted. On my heavy haul truck, it makes a huge difference over hilly braking conditions, upwards of a 200* reduction in temperature depending on overall duration and loading. Dropping from 650-700 down to about 500 taking some of my local hills. The slots aid in off road conditions... I have noticed a significant reduction in gouging since swapping out.

[stealthspoon]

where I used to live in Hawaii, I aways had a problem with warped rotors on my Toyota Sienna van. when driving home I had a long downhill trip that would heat up my brakes and warp them over time. I switched my rotors to cross drilled/slotted and never had that problem again. the cross drilled really does help heat reduction. it's not for just show or visual effect.

[rhkips]

I ran drilled rotors on my daily driver ages ago, and they started to develop fractures around the holes after a couple years, despite my being a fairly conservative driver. I think it's just the nature of the beast!

[nickdudem]

Drilled without slots will also groove your pad, lead to reduced swept area and premature pad wear. Some companies just dimple their rotors to prevent cracking, but this is pretty much for show as well. Cheers Mr. EE!