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

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

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.

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

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.

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

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.

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

Nice, objective and un-sponsored truth.

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.

PLEASE make a video about blowoff, diverter, flutter and all those kinds of Turbo Valves!

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.

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.

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!

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!

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.

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!

Wow! I had no idea that drilled rotors are not only not the best option but they are actually worse than the other options in high performance applications. I'm learning a truckload of new things with your channel, thank you! Subscription well earned!

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!

Each time I watch one of his videos, the more I wonder how his brain still fits in his skull. This guy is amazingly knowledgable and an excellent teacher. Keep up the good work boss!

My experience with drilled and slotted rotors is totally opposite of this video. I have two 2008 Chevy Impalas and with the stock vented and solid rotors, the brakes would heat up very fast under heavy braking, even normal driving going down hills or slowing from highway speeds. They would fade and eventually start to shake as they warped, but once they were cool they would stop shaking. I switch both cars to drilled and slotted rotors and all of those symptoms are 100% gone. The cars stop in shorter distances and I can brake MUCH more aggressively than with stock ones. I have yet to experience shaking or brake fade, even stopping the from 120mph to 0 mph. My brother has been running the same rotors and pads as mine on his 2003 Pontiac Grand Prix for 3 years and has had no issues with longevity, stress cracking or abnormal wearing.

Thanks man, I braked for this video.

You stated that drilled rotors are not being used in F1 racing. True, but there is almost (perhaps not at all) no steel in them. Street cars are mostly steel, so there is no comparison between those two materials, considering heat resistance (thus, warping), heat transference capabilities and mechanical specs. There should be no comparison between apples and pears. Just my humble opinion, with all due respect.

After watching this video I decided to buy cross drilled slotted rotors for my 2010 Pilot :D

I've had my cross-drilled AND slotted rotors on my car for 5 plus years and auto crossed with it, and they are holding up fine. No stress cracks. They do get hot fast but I attribute that to the fact that I don't have air ducts to help with cooling.

Can you do one on the advantages and disadvantages of different brake pads (ie ceramic) and also of different brake types (disc, rotor and air)?

Straight forward, educational, and most especially, thank you for not wasting my life with useless information or extended product promotion while explaining to me exactly what I wanted to know! There should be more quality people on KZfaq like you. My hat is off to you and your videos!

Well, this guy just totally changed my Amazon shopping cart. Thanks guy! Now I have like, $50 more in my wallet and the mechanic won't think I'm a douche for putting slotted drilled rotors on my Ford Focus!

When I bought my 2009 Accent SE, I installed drilled and slotted rotors and after 7 years and 50,000 miles I just replaced again, pads still probably had another 20,000 left but I just rather replace now than have the caliper piston at the end of its travel and for 91.00 pads on ebay included thought it was the right time. Old rotors didn't seem to have any stress cracks around the holes but some lines starting to appear.Probably saved 100.00 compared to a garageRemember also that most rotors are zinc coated so less prone to rust

Loved you in Napoleon dynamite!

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!

“Well because it looks awesome” quoted every single car guy right there 😂

I've bought StopTech drilled rotors as an OEM replacement before and didn't have an issue with them at all. (And this is when i was 17 and thought I was a gt3 driver)... You will likely never make the rotor fail during daily use.

Great video explaining the difference between the rotors! Nice to see a video explaining that although a tech might look as if it's "high performance" it might actually be worse than OEM. Great video!

Someone needs to make an educational video to tell people that brake rotors don't warp. I think you are the man to do it

You save people so much time, you should be given the Nobel prize for automotive information delivery!!

All my drilled/slotted rotors that ive used have always far exceeded my stock brakes. Daily driven aswell and no cracks or issues. And yes they did see track use every weekend. Stopping was improved, fade was non existent in street use anymore and the initial brake bite was much more noticable.

You’re explanations are amazing. You provide detail and make it so people who don’t know anything feel like they can do everything. Your examples are really relatable and helpful as well. Keep up the good work

THANK YOU for clarifying to the world that drilled rotors are simply cosmetic and that modern technology renders drilled rotors useless in the majority of applications. There are still many people out there that believe drilled rotors are the way to go, when for most applications involving hard use, it is not optimal.

I had cross drilled rotors for ten years without issues. Heat differential only becomes relevant in hard track racing. No street driven criss drilled rotor will ever get hot enough for it to be an issue. For street applications they are a huge improvement with zero chance of failure

Anddddd i just bought drilled and slotted rotors for my car. Oh well. Not like the car won't stop right lol

I've been riding motorcycles since the early 1970's. the 'new' disc brakes that were introduced were blank plates. In dry conditions they were way better than the older drum brakes (they had some serious fade issues), but in the wet you would get a film of water between the pad and the disc, plus the material issues you mentioned, and when pressed harder to try and slow down, the water would be suddenly be evicted and the front wheel would lock up, 90% of the time causing a crash. The first drilled rotors were amazing, they squeezed the water out the way. The compromise of less surface area was amazing. It would be great for you to do a video about the current motorcycle disc technology including drilled wave rotors (esp for Motocross), car technology in this area is way behind the motorcycles, bikes' designs are way more advanced, owing to the increased power outputs, and unpredictability of brakes than on a car.

I like how you use different colors on the whiteboard. It really helps understand the points you're making.

Something I always think is a good thing to look to for knowing what's best functionally is to consider what's used in heavy-duty applications that don't care about looks. Racing yes, but also things like trucks and trains - a lot of passenger trains use disc brakes. Typically very wide rotors - deeply vented - but no cross-drilling or slots, I don't think I've ever seen those features on a train. Same with aircraft, though larger aircraft usually use a totally different design of brake. A critical thing to keep in mind with any of these things is that there are a series of factors that must be compromised on, the winning arrangement depends on which are most important. Mainly: Performance, cost, weight, and longetivty. Racers care about performance and weight, with little regard for longevity or cost. OEMs care mainly about cost and longevity, though performance and weight are considerations. The trains I mentioned and heavy trucks care about performance and longevity, with basically zero regard to weight and some to cost.

Love your videos. Crossdrilled rotors are often used for qualifying where a team will be replacing the rotors before the actual race.

I've had my Brembo Gran Turismo, 4-piston cross drilled rotors for over 7 years on my car. Not one crack yet, and I haven't had to replace my rotors.

I almost purchased drilled and slotted Akebonos and you just saved me a bunch of money. Thank you

THANK YOU! Seriously, so many so called "car" people I know keep trying to tell me that going Drilled, Slotted, or BOTH is the "best" for a car when in reality it's not. I've been convinced that vented has been the best for real every-day purposes because it's not like you are going through immense heat changes every day. You need the surface area to stop efficiently and to maintain adequate pad wear or else you will end up with either pads that are worn funny or rotors that don't maintain an even surface that will start making tons of noise over time. Hard to tell this to ricers when I work on their cars... it's their money I suppose!

Good explanation and comparison. I would add that drilled rotors reduce rotational weight. Slotted rotors probably do also, but maybe not as much. I'm told a drilled rotor with chamfered holes does better as resisting cracking. Probably better on brake pad wear also.

"Because it looks awesome and well, it does look awesome!"

May be worth pointing out that the straight vanes of standard vented rotors still act as an air pump. So if you are going to put in a venting system, the more you can focus it toward the center of the disk, the better. The curved vanes make a more efficient pump, so they move more air, and cool faster. The down side is that they are directional and more expensive.

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

my civic has slotted vented drilled pads and painted red. plus ceramic pads. i beat ferraris and adds 50 hp each

AP Racing or Akebono are the high-end manufacturers and maybe Brembo. Cant go wrong with that lot if you have deep pockets. If not the dep pockets, EBC Brakes are an excellent substitute.

Thank you so much for your stuff ... couple months ago I should have died in a car accident (provided I was following at the "recommended distance" on the highway), I just ended up ruining my brakes and rotors ... along with my front bumper, passenger headlight assembly, and I think the water pump. Been driving around with a wobble anytime I hit my brakes above 45mph. Just now getting around to changing them. This video definitely was more helpful than any review I could have read.

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.

Drilled rotors are commonly used in drifting because the brakes are hardly used so they don't see the drawbacks from other forms of racing but they reduce weight

Thanks for the informative video! I'm in the middle of ripping out the front manual drum breaks on a '65 Mustang and was trying to figure out if it was worth investing in drilled and slotted disk rotors. Looks like I'll be spending a little more, but I kinda like the car so I suppose it's worth it.

Other things being equal, the only thing that matters in brakes is surface area. If you drill out metal, you reduce your surface area. This guy is honest and knows what he is talking about. Drilled discs are for people who don't think and don't understand engineering.

Stock OEM rotors with Upgraded pads is all you will ever need for the occasional track day and street use, I could see Slotted used in dirt or mud applications. Good explanation.

IIRC high end "drilled" rotors are actually cast with the holes in them making them stronger compared to normal rotors that have holes drilled through them. And while they have less braking surface area and less thermal mass they do have more cooling surface area making them dissipate heat faster, correct me if I'm wrong.

Anywhere in this video does he mention that drilled rotors decrease unsprung weight? It bothers me when he says "there's no reason". There's always a reason when you build a race car or street car. Often, cost and application. This is the second video I've watched where incorrect conclusions or assumptions are made without asking all the questions about the application. The Ford GT, which is a purpose built race car for the street used drilled rotors (among many other supercars). I'm sure material removal, heat dissapation, unsprung weight all came into play and were measured. They didn't just drill into them "for some reason". They test everything. "Because they look cool", you call yourself engineering explained...that statement is a design statement or marketing and subjective.

I believe you are 100% correct on all points. Imagine my dismay when my 2007 Corvette ZO6 had drilled and slotted front rotors. I guess GM didn’t get the memo, and wanted to impress potential customers.

You are awesome, my friend... These videos are some of the most accurate and trustworthy information available, without any b.s. at all. I learn something new every time I see one. Keep up the good work, brother.

have you ever watched a race or worked on a pit crew I have and drag cars and nascar use drilled and sloted rotters

This cleared up a lot of controversy, thanks

In defense: Drilled rotors should have less problems handling rain and mud, since the holes give fluid on the rotor or pad somewhere to go without all running or caking up on the pad. Thanks for this video! It simply explains things that should be easy to understand but get lost in all the debate and rumor.

nice vid, at the beginning i thought he was going to say and promote the slotted/drilled brake pads are the best etc. but he didn't and he knows what he talking about.

Wow I always just assumed drilled was the best, just because everyone uses them on their high end cars. I guess I know why the P1 has those big plain vented rotors now.

I thought the drilled rotors were popular to save weight. Kind of like a lightened flywheel. Itll take less force to spin something that weighs less.

Thanks I now have a drilled and slotted drum brakes for my fronts... and a brembo plastic brake cover glued to it.

I'm getting a big brake setup for Time attack, and you were the only one to actually say what the +/- are of each option 🙏🏿 Also u saved me money 😉

drum brakes all round for me please

Mono block vs two piece calipers

yo bro I'm a fresh men in corona high I have auto and I saw your video on Monday night and on Tuesday morning In auto my auto shop teacher showed us drilled rotars I was the only one who knew why they where drilled, thank you for giving me some knowledge

Just want to add that both the vented examples that were drawn act as air pumps, one relies on just centrifugal forces while the other uses a bend to assist and to possibly also increase surface area inside the vents.

Break pad please!!

I'll preface by stating i'm a Chief Engineer. You remind me of a lot of junior engineers just out of school. By that I mean you begin your sojourn in life believing you have a quick (albeit wrong) answer for everything. If you think AMG attaches drilled rotors to their products because it looks cool, I suggest you re-evaluate your "opinion". Engineers are essentially scientists and as such Engineers present facts to reinforce their hypothesis. RR C/E P/E

Every plain surface rotor I had on my cars very quickly warped - usually before the first pad change. The drilled/slotted rotors have never warped on me - even after a couple of pad changes (didn't have a chance to check the performance beyond that as I got a new car which came stock with plain rotors).

I did put drilled and slotted rotors on the front of the 01 Ford Escape I owned years ago. I will say they stopped far faster in the rain. I only use ceramic pads now too.

I always go dimpled.

If you suspect your brake rotors are very hot from current aggressive driving, or some sudden stops, do not sit with the brake pad on the rotors. Rather, apply light pressure, and let the car roll a little. Otherwise brake pad material will adhere to the rotor causing a pulsation in the pedal.

Sweet OTR plug. I'm a fan. nice exlaination. you probably then could talk about different compounds, types of metals but then it would take a hour and nobody would watch.

I have researched this topic when I was looking at purchasing new rotors and came to exactly the same conclusion which led me to buying non-slotted or cross drilled rotors becasue i didnt want cracking and i didnt want to have to change my pads more frequently.

So AMG and Ferrari sacrifice brake performance for "cool looks"?!! I don't think so.

He looks like Jim Bob from the Waltons

dude, I love your vids and love that you are not crazy bias on your "experiments"...thanks for breaking things down quick and easy to all us simple people that know just enough to have a beginner conversation...lol keep it up!!!

Vented+slotted in my opinion, especially if you are on a budget. The reduced weight and airflow is so minuscule in drilled you couldn't tell, however the risk for the discs cracking is a real concern.

Why not do some actual tests on different disc designs to show any benefits etc?

does the downsides of drilled brake discs applies to drilled carbon brake disc like those in Porsches etc?

Love your videos. Brake rotors with holes do not create a fast temperature change. They cool off just about as fast as ones without the holes. I've seen temp tests measured on real street testing. But you are correct about surface being reduced with the many holes. I believe most all rotors are vented these days. And that is about the only thing that really matters. Temps do change higher and lower which is dependent more on racing and type of track. Not street use. For street use these do nothing to enhance the performance..or change temperature to benefits. Only the looks of them is the change. It is why you don't see spec temps listed for slotted or drilled rotors. The temp changes are really insignificant until you get to really racing around a track.

I looked up your video because I was looking to fit crossdrilled discs on my car. The reason was that the wet performance on the standard ones is terrible to the point that it's hard to stop the car! I live in the west of Scotland, which is a notoriously damp part of the world. I wasn't aware of the cracking issue, so I'll keep that in mind when I speak to the brake fitter.

I purchased cross drilled/ slotted rotors along with a ceramic or "Red series" pads. My Stage 1 2010 Passat stops so hard it's actually dangerous. My question is in regard to the effect this type of setup has on the factory abs which my brakes ( being able to easily lock up all 4 corners now) can seemingly render useless. Could you do a video about the abs system and brake system upgrades possibly? Thanks for the info and great brake rotor video.

My grandma uses slotted drilled rotors on her wheelchairs and every time she stops her wig, false teeth and depends underwear fly off.

I bought the slot and vented over the slot and drill as it just made more sense in keeping the brake pad clean. The drill is just unidealisttic as hot air will just get onto the pad, negating its effectiveness in stopping power. More surface equals better bite, kind of like on a solid vented rotor. I do notice a big improvement in the stopping power when I tap on the brake versus mashing the brake pedal hard just to get it to slow down in hot weather the stock rotor just couldn't do the job as well as expected. Sometimes, when in an emergency brake on the highway, I felt like I had to swerve out of the lane just to avoid hitting the car in front because it is just not slowing down quickly enough. With this new upgrade, I rarely had to put force down on the brake pedal to get it to slow down. I just gently tap tap the pedal and my heavy suv slows down dramatically with very little effort. I have not slam on the brake hard to see how effective it does in an emergency brake when someone cuts me off on the highway or a hazard in the front. As far as the wear goes...only time will tell after I put a couple hundreds on it. To see if the trade off is worth it by going to a slotted performance rotor over the stock.

As a Parts Specialist, Stoptech slotted/vented rotors is all I run & recommend for cars that are going to be ran in light racing events like Auto-Cross. All the teams in Pirelli World Challenge use them also. I've seen other event goers that used drilled/vented only to have cracks appear. I agree here. They may look cool but drilled offers no advantage with today's performance pads.

But brake rotors with holes have less mass, less rotating mass!

Drilled er, found out she slotted, now im leaking fluid :( . Glad I vented about this

I gave a 1997 crown Vic a second life and love driving it and I’m a bit of a lead-foot. But, as I had to completely rebuild the brakes I went with drilled and slotted rotors. I do not race this car, just a fun commuter. These more expensive and yes “cool looking” rotos lasted less than 6-months and are now VIBRATING like crazy. Under normal use they can’t slow down a big car and last... I have to replace them with solid or slotted.

pretty good description of rotors, slotted rotors are made to cut a fresh surface to the pads and keep them as flat as possible always giving a full pad surface for the most friction possible. the draw back is after the pads are done so are the rotors and they also have some vibrations from the slots scraping the pads at slower speeds. pretty sure formula racers use carbon fiber rotors that are able to handle much higher temps and reduce weight.