How Can Brakes Cost $10,000? The Brilliance Of Carbon Ceramics

hello everyone and welcome in this video sponsored by brembo i have a cast iron brake rotor in front of me as well as a carbon ceramic brake rotor i think a lot of people realize the carbon ceramic rotor is quite a bit more pricey but you might not realize why or what the advantages are just looking at it i mean it's a brake rotor it's difficult to see how it can increase your grip or improve your ride quality and yet it does so in this video we're gonna be explaining why these rotors are so expensive and 10 advantages they provide all of which will help explain why this technology developed from motorsports has made its way into road cars as original equipment so let's start off with the big question why so expensive well there's really three reasons first the materials used iron is significantly cheaper than the high grade carbon used on carbon rotors carbon ceramics also use higher quality fasteners because these discs tend to last a lot longer so all the materials used need to last longer second and this is a big one is the manufacturing process brembo says it takes 90 minutes from start to finish to crank out a single cast iron rotor on a continuous production cycle it takes less than a minute per part a carbon rotor on the other hand has a much more intense process end to end it takes about three weeks to create a single carbon rotor the process is pretty wild it involves specialized equipment and many manual steps there's a really cool video on how they're made which i'll include a link to in the video description if you're interested so materials time and finally scale these brakes not only have low volume batch sizes they're also pretty low volume parts especially in comparison to cast iron rotors so when you add all this up you might have a set of cast iron rotors for around a thousand dollars whereas the option for carbon ceramics on a new vehicle can easily be ten thousand dollars so the question becomes are they worth it well obviously i think that is ultimately up to whoever is buying them but let's talk about 10 advantages that you get with carbon ceramic rotors the first is the most obvious one so we won't spend much time on it brake fade carbon ceramics are the go-to and professional racing because you get consistent brake pedal feel and virtually no brake fade even at really high temperatures and repeated use now that doesn't mean you can't achieve the same thing with iron rotors an appropriately sized iron rotor can allow for consistent track performance it's just going to be significantly heavier than an equivalent carbon ceramic rotor that leads us to number two weight and this provides a whole host of benefits so both of these discs here are made for the same vehicle the iron rotors are 398 millimeter in diameter and 36 millimeters wide the carbon ceramic disc is 400 millimeters in diameter and 38 millimeters wide so you'll notice that dimensionally they're nearly identical with the carbon ceramic rotor being just slightly larger however the weight difference is astonishing okay i'm going to embarrass myself to prove a point so i have the carbon ceramic in my left arm my weaker arm and i have the cast iron rotor in my right arm my not as weak arm and as you can see i can easily curl the carbon ceramic with my left arm and to all the gym bros out there that can curl 40 pounds congratulations i'm very proud of you i'm sure you'll let me know in the comments uh but i cannot the iron disc actually weighs 36.4 pounds or about 16 and a half kilograms the carbon disk weighs just 16 and a half pounds or about seven and a half kilograms so while the carbon disk is actually just slightly larger dimensionally the iron rotor actually weighs more than twice as much i find that very impressive of course the majority of this weight difference comes down to the materials used iron has a density of around 7.3 grams per centimeter cubed whereas carbon fiber composite has a density around 2.3 grams per centimeter cubed you'll also always see an aluminum bell used with a carbon ceramic rotor whereas often on iron rotors you will have an iron belt unless it's a two piece rotor like the one you see here so ultimately you're taking weight out of the car and removing weight means the car does everything better braking accelerating and cornering so that's a good thing all in all on a single car switching from these to these would take out about 80 pounds or about 36 kilograms that is quite significant for number three we're talking rotational inertia so anything that has to rotate on your vehicle whether that's the wheels the tires the drive shafts differential transmission gears oh yeah and your brakes anything that rotates causes an additional penalty on your vehicle's acceleration because not only do you have to accelerate this mass longitudinally like yourself sitting inside of the car but you also have to accelerate this mass rotationally so the more mass an object has and the further that mass is from the axis of rotation the more rotational inertia that object has and that's a bad thing how much of a bad thing well consider this on my own car i switched over to smaller lighter wheels pulling out 34 pounds of rotational mass by doing so my 0 to 60 went from 3.4 seconds down to 3.3 seconds just by removing 34 pounds on a card that weighs over 4 000 pounds okay so for number four grip and reasonably you might wonder how in the world can something that never comes into contact with the ground improve the grip of a car well if all roads and driving surfaces were perfectly smooth it wouldn't but that's simply not the case so let's talk about unsprung mass cars have a suspension whatever that suspension is holding up is the sprung mass whatever that suspension isn't holding up like the wheels tires and brakes is the unsprung mass your suspension's job is to keep your tire in contact with the road and also improve ride comfort which we'll get into later if you're going over an uneven surface the suspension is trying to push the tire into the pavement as you drive over subtle elevation changes a heavier tire wheel and brake combination of course has more inertia taking more time to react to those elevation changes whether it's forcing the wheel up or down and when you hit a bump that heavy unsprung mass is now sending a force up through the suspension to the chassis and upsetting the ride the lighter the unsprung mass the lower this force and thus the less it upsets the ride so let's say between the large wheels and tires required to accommodate these large brakes plus these large brakes plus bits of the suspension we have a hundred pounds at each corner of unsprung mass well by switching over to carbon ceramics we're taking out 20 pounds or about 20 percent of that unsprung mass at each corner this means your suspension can better control your wheel movement thus improving grip and this all carries over into number five ride quality the simplest way of thinking about it is the more stuff you put above the suspension the better your ride quality because the suspension can then do something about outside forces but the suspension has much less control over what's supporting it so by reducing unsprung mass you maximize how much of the overall mass your suspension controls and can improve ride quality it's worth mentioning that tires also act like a suspension so you can still somewhat improve the ride quality due to unsprung mass through tire selection number six another benefit from a fuel perspective is that carbon ceramic rotors are dimensionally stable so what does that mean well unlike an iron rotor a carbon ceramic rotor won't have any disc thickness variation occurring so it will maintain a nearly identical thickness throughout its life this means you won't have any brake roughness or jutter when you're pressing down on the brake pedal so for example when you get an iron rotor really hot that temperature causes the rotor to expand and deform this deformation means at really high temperatures you can get brake jutter carbon ceramics have extremely minimal differences in dimensions due to temperature so you don't get that breaking roughness due to rotor deformation there are also practical benefits of carbon rotors like number seven longer life now this is a big one because brake rotors are a wear item so the immediate concern is well i'm gonna have to spend thousands and thousands of dollars every time i have to replace these the reality is you probably won't have to replace them for your ownership of the car now it's impossible to predict your exact use case so obviously i can't say you'll never have to replace them if you're taking your car to the track every weekend yeah eventually they're gonna wear out but if it's a daily driver that you're putting a hundred thousand miles on during your ownership well it's probably going to last and keep in mind these styles of brakes are often offered on ultra high performance cars and exotics cars that typically aren't used as daily drivers where most owners won't even come close to wearing them out especially if they're only used on the street to better illustrate this brembo says that in a track environment a carbon ceramic disc will wear at a rate up to 10 times less than a cast iron rotor and having longer rotor life leads to another advantage number eight less brake dust so less brake dust is both an environmental as well as an appearance advantage long term brake dust can also damage the surface of your wheels so it's good to clean it off periodically so the explanation here is very simple most brake dust comes from grinding down the iron rotors and since the carbon rotors don't have any iron in them and don't wear as much you don't have nearly as much brake dust carbon ceramic rotors can reduce brake dust by as much as 90 percent number nine you have virtually no corrosion with carbon ceramics you've probably noticed your iron rotors with a lot of surface rust after getting wet from the rain that's the iron in the rotors reacting with oxygen and water since there is an iron in carbon ceramic rotors you don't have to worry about rust and this also helps cut down on brake dust and finally we get to number 10. okay this one's subjective they look awesome you don't get to see all of the performance enhancing parts of a car you can't see the engine internals or gears inside your transmission or differential but this is one that you most definitely do see and it's cool that you can visually differentiate it looking at it closely you'll see little cracks creating a unique pattern on the surface these cracks are an intrinsic characteristic of the rotor and nothing to be concerned with the cracks are only on the outer surface and they don't change nor do they impact the performance of the rotor but it does give the rotors a unique immediately recognizable appearance and i think it's fascinating to look at and so for the many many advantages i've listed you'll see these carbon ceramics used as original equipment on cars like the cadillac ct5 the blackwing corvette zr1 nissan gtr lexus rcf ford gt pagani wyra and plenty of other exotics brambo actually has a pretty cool story starting as a small italian shop in 1961 to being a major global brand used by pretty much all of the original equipment manufacturers today even my own cars use their products as original equipment they're also in all kinds of different motorsports today as high as formula one having gotten started in racing in 1975 with ferrari so a big thank you to brembo for sponsoring this video and thank you all so much for watching if you have any questions or comments feel free to leave them below

Channel: Engineering Explained

Views: 352,175

Keywords: carbon brakes, carbon, carbon ceramic, carbon vs iron brakes, iron rotors, carbon ceramic brake rotor, brake rotors, carbon ceramics, carbon brake rotors, brembo brakes, brembo carbon, brembo carbon ceramic, brembo brake pads, brembo brake rotors, brembo rotors, brake pads, brake test, engineering explained

Id: VBd9y3mxzCM

Length: 11min 58sec (718 seconds)

Published: Fri Dec 10 2021