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Let's talk rotors

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Old 10-31-2016, 06:24 PM
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Default Let's talk rotors

I read a lot of things about rotors, mostly contrary to my experiences. So I just thought I would start a thread and see what others experiences are. Here are 2 pictures of my ebay drilled and slotted rotors I bought back on 5/2009 and 142,000 miles ago. I think they are holding up rather well for "cheap" rotors. They were like $125 shipped when I bought them and they came with ceramic pads. For sure I've replaced the pads since then.
This is my daily driver, I do not track this car so there is no "real" abuse only occasional highway play.

Drilled and slotted you may ask, yes the drilled part helps to keep the rotor cool, yes cooler than a plain blank rotor and slotted to help clean off the pads.
Attached Thumbnails Let's talk rotors-imag0865.jpg   Let's talk rotors-imag0866.jpg  
Old 10-31-2016, 06:49 PM
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I've always found drilled and slotted to be more visual appeal then any real benefit to a non-track car (and very limited, or even detrimental with modern pads on the track). You aren't going to be pushing the car enough to need to vent gas and only the worst stop and go will maybe bump your rotor temps up. But all those extra biting edges will lead to quicker break wear.

Last edited by 99SSJarhead; 10-31-2016 at 08:26 PM.
Old 10-31-2016, 08:13 PM
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I used to be a big fan of the ebay slotted and drilled deal until I got two sets of bad rotors and pads that squeal to no end. I have never had more difficult time breaking in a set of pads before these. I've never had a set of brake pads glaze on me, ebay was the only time. Even autozone never gave me a problem with break in. On top of the fact that I have seen pictures of them cracking made me a firm believer that blank is always better for stock brakes at least. On a 4 or 6 piston caliper I could see the need for them to let out more heat, but I don't think we produce enough heat for highway/city driving and the occasional stabbing of the brakes from a high speed slow down.

I say any blanks will do, autozone isn't bad. But I'll spend the money on pads next time and skip ebay.
Old 11-01-2016, 08:04 PM
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Originally Posted by LS1121
Drilled and slotted you may ask, yes the drilled part helps to keep the rotor cool, yes cooler than a plain blank rotor and slotted to help clean off the pads.
No it doesn't. The metal of the "drilled" part just cools faster than the rest which actually causes metal fatigue. You don't want rapid cooling of hot metal. Your rotors being able to handle heat is more important than cooling fast. Quality blanks will always be best. Slotted and drilled are just for aesthetics at this point in braking technology.

It's impressive that you got so much mileage out of them, but they do have some pretty good grooves in there.
Old 11-01-2016, 09:22 PM
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Originally Posted by justin455
No it doesn't. The metal of the "drilled" part just cools faster than the rest which actually causes metal fatigue. You don't want rapid cooling of hot metal. Your rotors being able to handle heat is more important than cooling fast. Quality blanks will always be best. Slotted and drilled are just for aesthetics at this point in braking technology.

It's impressive that you got so much mileage out of them, but they do have some pretty good grooves in there.


sorry wrong again. My Corvette and many other super cars come standard with drilled rotors, I guess all the engineers of the world are just stupid.

Yes many miles for such a small price. I'm trying to decide if I will get another set of these or just drilled like my Corvette.
Attached Thumbnails Let's talk rotors-bugatti_veyron_brake.jpg  

Last edited by LS1121; 11-02-2016 at 09:59 AM.
Old 11-01-2016, 10:20 PM
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Originally Posted by LS1121
[/B]
sorry wrong again. My Corvette and many other super cars come standard with drilled rotors, I guess all the engineers of the world are just stupid.

Yes many miles for such a small price. I'm trying to decide if I will get another set of these or just drilled like my Corvette.
They do it for aesthetics, plain and simple. The benefits are neglible for slotted and nothing for drilled with modern brake pads while the detriment for slotted is eating through pads quicker and possible cracking for drilled during heavy duty use. Your Corvette and many other supercars spend their lives putting around on the daily grind, so the detriments of those brakes aren't ever an issue (aside from increased pad wear) while they get the benefit of "Hey, cool! Drilled rotors!" from the average person. I trust that their engineers know about this trade-off and really don't lose sleep over it.

Though there are a different set of engineers out there that lose sleep over brakes. They work for racing teams and I can't think of a single one that uses drilled rotors.

This is an F1 rotor.

Let's talk rotors-wfhlkyb.jpg

This is a rotor from the Porsche 919 LMP1 car.



And this is the rotor from the C7.R race car. It will benefit from slotted rotors and decreased pad life probably isn't an issue.



Like I said, I'm impressed you had as a good an experience with them, but that doesn't change facts and certainly doesn't make the facts I stated wrong. Drilled rotors weren't even invented for cooling purposes. They were invented because old brake pads used to emit gas as they got hot and that gas would build between the rotor surface and the pad surface, causing ineffective braking. The holes allowed that gas to be pushed out of the vented middle of the rotor. Modern pads don't do this anymore so drilled rotors are nothing more than a relic of racing past that trickled into street cars for aesthetic purposes.
Again, blank is best.
Old 11-02-2016, 08:55 AM
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Originally Posted by justin455
They do it for aesthetics, plain and simple. The benefits are neglible for slotted and nothing for drilled with modern brake pads while the detriment for slotted is eating through pads quicker and possible cracking for drilled during heavy duty use. Your Corvette and many other supercars spend their lives putting around on the daily grind, so the detriments of those brakes aren't ever an issue (aside from increased pad wear) while they get the benefit of "Hey, cool! Drilled rotors!" from the average person. I trust that their engineers know about this trade-off and really don't lose sleep over it.

Though there are a different set of engineers out there that lose sleep over brakes. They work for racing teams and I can't think of a single one that uses drilled rotors.

This is an F1 rotor.



This is a rotor from the Porsche 919 LMP1 car.



And this is the rotor from the C7.R race car. It will benefit from slotted rotors and decreased pad life probably isn't an issue.



Like I said, I'm impressed you had as a good an experience with them, but that doesn't change facts and certainly doesn't make the facts I stated wrong. Drilled rotors weren't even invented for cooling purposes. They were invented because old brake pads used to emit gas as they got hot and that gas would build between the rotor surface and the pad surface, causing ineffective braking. The holes allowed that gas to be pushed out of the vented middle of the rotor. Modern pads don't do this anymore so drilled rotors are nothing more than a relic of racing past that trickled into street cars for aesthetic purposes.
Again, blank is best.

Old 11-02-2016, 09:56 AM
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Well since my 2 sets of OEM GM rotors both warped out and made me nuts and I installed my poor old useless drilled and slotted rotors that lasted all this time perfectly without issue I'll just have to buy another set. My brakes are still good I was just thinking since I'm replacing all the bushings and ball joints in my front end I would just go ahead and do the brakes at the same time. It's funny though all I did was change the rotors and my brake pedal has been pulse free for all these years. I guess more air really does not mean more cooling.

Bugatti Veyron gee I can find pictures too.
Attached Thumbnails Let's talk rotors-bugatti_veyron_brake.jpg  

Last edited by LS1121; 11-02-2016 at 10:02 AM.
Old 11-02-2016, 11:15 AM
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Don't get defensive now, he's right. In a true performance application like the wheel to wheel road racing I do, blank rotors are where it's at. Go to an SCCA US Majors Tour event. Not one team, from the little guys like me to the million dollar teams that pull up in semis run drilled and slotted rotors, because they are useless.

For a DD, sure they look cool.
Old 11-02-2016, 11:22 AM
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I'm enjoying this thread
Old 11-02-2016, 12:56 PM
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Originally Posted by LS1121
Well since my 2 sets of OEM GM rotors both warped out and made me nuts and I installed my poor old useless drilled and slotted rotors that lasted all this time perfectly without issue I'll just have to buy another set. My brakes are still good I was just thinking since I'm replacing all the bushings and ball joints in my front end I would just go ahead and do the brakes at the same time. It's funny though all I did was change the rotors and my brake pedal has been pulse free for all these years. I guess more air really does not mean more cooling.

Bugatti Veyron gee I can find pictures too.
Most "warping" rotors are caused by the pads leaving material on the rotor when they get hot and then are held in one spot, not the metal of the rotor actually warping. It's just build up. Slotted rotors can help with that. Or you used better pads or didn't get them hot enough, holding the brakes in place.
The holes did literally nothing to help cooling or longevity. That's just a fact.

Also F1, Le Mans prototype endurance racing, and C7.R > Bugatti Veyron. Again, the Veyron will spend it's entire life sitting in a garage or putting around town. The race cars spend their entire life racing. That doesn't even take into account the Veyron has carbon ceramic rotors which will have different heating and cooling characteristics. They might not experience the metal fatigue of regular cast iron.

That also doesn't take into account that drilled isn't actually how quality rotors are made. Cheap ones are drilled and fail. Rotors like on your Corvette, the Bugatti Veyron, and other supercars are cast with the holes in place. Casting the holes eliminates the danger of cracking for street driven cars while still giving the desired aesthetic. On the track, they're still gonna crack eventually where a blank rotor wouldn't.

Like I said, I'm happy those rotors worked out for you and you should keep on buying them since they do. I'm just saying the holes aren't the reason they worked well and the holes don't help with cooling. They're just there to look cool. For actual braking performance and longevity, all other things being equal, blank is better than slotted and especially drilled.
You really should replace those rotors though. They're most likely done for with those grooves in them.
Old 11-02-2016, 12:59 PM
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Take those cheapie drilled rotors to the track and see how fast they start cracking around the holes when they get heated.

The C7R looks to have the AP racing J-slot rotors. wish I could afford that set-up on my 1LE.
Old 11-02-2016, 12:59 PM
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Car companies use drilled rotors to easily impress people like you and sell more cars. All holes do is take critical mass away from the most important part of the rotor.
Old 11-02-2016, 06:08 PM
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Originally Posted by LS1121
Well since my 2 sets of OEM GM rotors both warped out and made me nuts and I installed my poor old useless drilled and slotted rotors that lasted all this time perfectly without issue I'll just have to buy another set. My brakes are still good I was just thinking since I'm replacing all the bushings and ball joints in my front end I would just go ahead and do the brakes at the same time. It's funny though all I did was change the rotors and my brake pedal has been pulse free for all these years. I guess more air really does not mean more cooling.

Bugatti Veyron gee I can find pictures too.
Bugatti huh? So how exactly is a carbon ceramic rotor like a metal one?

Been over this already, oem rotors are junk, you put better quality rotors on (drilled or not). If you would have put quality blank rotors on you would have the same results.
Also please EXPLAIN how all these guys road racing with blank rotors are not warping them??? Everyone is just getting lucky?
Ok but lets plat devils advocate and say they do produce a cooling effect. Do you really think you would see that street driving??? You really think the rotor is going to get to the point its so hot that it needs additional cooling to be effective on the street? Really?
Ok so say they produce a cooling effect at race track situations, oops wait what does brembo say about it?
"NOT FOR TRACK USE"
http://www.tirerack.com/brakes/brake...Drilled+Rotors
If they really have a cooling effect and help braking why would brembo, one of the biggest brake companies in the world, advise against using them for performance braking???

FYI
Ferrari race cars




You can see they use brake ducts for the cooling effect, but why no drilled rotors if they add cooling?
Old 11-02-2016, 08:22 PM
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interesting.
Old 11-02-2016, 08:50 PM
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You had all the intentions of a possitive thread but after 2 posts that changed. Glad the rotors you bought worked good for your driving style and pad setup.

Unfortunately, there are more of us lsx spirited drivers than driving to work drivers in our lsx. So your automatically preaching to the wrong choir even tho u have good intentions.

What could have been left unsaid was when u said my c6 has drilled rotors so the engineers are stupid i guess. Nobody likes when you **** talk the creators of our kids.

Curious if you would have gotten the same rotor results using more aggressive material like hps or semi race compound.
Old 11-02-2016, 08:53 PM
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O and btw, bugattis have drilled rotors for aestetics only, because everytime a civilian tries to do 200 in one, the dont stop by using the brakes. They use their surroundings to slow down.
Old 11-02-2016, 09:13 PM
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I'm not a fan of factory replacement, one-piece slotted and/drilled rotors. Like others have said they are not a performance upgrade on a street car. My car has them because they were on it when I bought it, but I think they look ricey. 14"+ Brembos with slotted/drilled rotors don't look ricey.

Some companies who build track car pieces and race prefer and use solid rotors in their brake kits. Griggs for example is pretty much the most respected name in road racing for Mustangs and their brakes use solid rotors.


Old 11-02-2016, 09:29 PM
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OP are those brakemotives? They kinda look similar to mine, and ive had great results with mine too. I feel aslong as you have good pads, any decent rotor should do fine. However, everyone else is right, there was a video a while back that showed how blank rotors actually performed better than drilled and slotted. I cant find it anymore tho.
Old 11-03-2016, 06:20 AM
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I need to find the pictures of my drilled and slotted rotors after 1 day at Sebring Intl. Brand new rotors almost came apart they cracked in so many places. Just can't take the heat like a blank can.


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