Do Performance Brake Rotors Have Better Cooling?

You did it wrong, when they say cooler they mean it looks better. a common mistake.

I think this is just a result of testing parts intended for the track vs parts for the road. People convince themselves that race parts must be better on the road because they are designed for harsher conditions but this refutes that. Very useful as I am going to need new rotors in the future and with my car being an old Lincoln, I never really thought I'd need performance rotors, but I really wanted them. But it looks like you've saved me some money! It may be a tricky one to test but if you're considering doing it, how dusty performance pads get would be extremely useful as I think that is what will do more for braking performance.

nicely done test. Something to consider is that if the aftermarket rotors were brand new, perhaps they have a protective corrosion resistant coating (many rotors do for shipping) and these coatings usually take a while to burn off, and these coatings burn HOT. Just something to keep in mind.

I have heard that the slots or vents in performance rotors are not intended to cool the rotor. But rather to allow the vaporized brake pad gas off out from under the pad helping relieve brake fade. Also to help take heat out of the area between the pad surface and rotor not the rotor as a whole. Interesting test and your work into it is commendable. The smaller mass should have a faster temperature change rate. Heat up and cool down faster between applications

I can see what it is that you did wrong...you had the winter air still in the tires. you need to drain the winter air and put in the summer air so it keeps the blinker fluid cooler

This video is (possibly) a great example of confirmation bias. Because I think it's logical that the rotors have a better design, I did want to see if there's a reason for which they'd perform better than the stock rotors. Based on my data alone, I cannot confirm that, but I'm trusting that Science of Speed's data is accurate. Also, the sweat and grease stains are just make-up, you don't really believe I spent time in a garage working on a car, right? 😂 Follow on Instagram if you like to go fast! www.instagram.com/engineeringexplained/

I once sprayed WD40 on the brakes to clean them so they will brake better. Forgot to clean it off. Massive surprise at first intersection

How about actual performance? Like stopping distances, brake fade?

Professionalism achieved dude

I know it takes a lot of work to do these tests, they are informative and interesting. Thanks for doing it!

I search all over all the time... for everything about cars and part etc... and I always find my self back here on your channel... I just want to also say that you’re the best and amazing at what you do... and thank you!

Absolutely, YES. I drive my E350 van hard and I kept warping the rotors. I bit the bullet and bought a set of performance rotors and I've never had a problem since.

This and ChrisFix videos is all I need.

Learning physics hasn't ever been this much fun. You're the best "teacher" EE!

Really interesting testing and video. Weight reduction & better heat dispersion during hard braking; seems like a win/win to me.

Very nice and useful tests and analysis. I think the mass had a significant impact. The cooling for directional vanes is better but that when you are on a straight at 200kph which makes the difference. Less mass is better because of less unsprung weight but you need a minimum thickness otherwise they will crack. Racing rotors are two piece free floating and they are small in diameter unlike on supercars, but they are thick. However, with air ducts that blows a high flow of air in the middle, they can stay cool for tens of minutes of racing. The slots are also necessary for off-gassing. Racing pads which you cannot use on roads, are also used. If you want good brakes you want multi piston calipers, good pads, free floating discs not too big, and air ducts, racing fluid. Air ducts with good pads are still ok.

As an ME this was a great video. Other factors to consider are friction as the stock rotors you tested looked to be used and the slotted rotors looked brand new. Generally rotors need to be "broken in" to the brake pads. If the same pads were used throughout the experiment they may have broken in to the stock set of rotors creating higher friction points on the slotted rotors. Incidentally came across this video looking for upgrades to my stock brakes.

A lot of folks asking about why I didn't test stopping distance since we're talking about brakes. Conveniently, my very first article for Road & Track explains why, and was released today! www.roadandtrack.com/car-culture/a10316984/why-bra…

Thanks for addressing the mass difference, and the difference between your tests and higher-temp track testing.

I'm not sure you are taking all things into consideration. Rotor temperature alone may not be the sole determining factor of performance. What if the rotors are carrying away heat from the pads more efficiently? Or, with the slotting allowing gas to escape may be offering additional friction, resulting in the higher temperatures, but increased braking as well. I'm not saying you're wrong. Just that, I'm not sure that you are right.