Drilled and slotted rotors.

[don4331]

Drilled rotors came into existence back when the glue that held the asbestos together tended to form a gas layer between the pad and rotor. As the gas held the pads off the rotor, brakes would "fade" rather dramatically. The solution was to drill the rotors, allowing the gas to flow through the holes and stopping was maintained. It worked on those nice Porsche's so very one wanted them.

But fast forward 3+ decades and the material is no longer asbestos and the glues don't off gas near as much. So, drilled rotors now hurt ultimate stopping performance, much the same way a treaded tire is worse than slicks. If you look at Formula one, they no longer drill their rotors. Some have even exchanged the vanes for series of small holes...

So, for mall crawlers, get the drilled rotors. For the rest of us, undrilled provide equal or better performance. The high end rotors with directional vanes that pump air thorough the rotors have their place at the track where you get air moving thorough the rotor before the next corner, and drilling may still have a purpose there as it would allow slightly more cooling.

As noted, its pads sitting on the hot rotor that warps. Interesting that ceramic pads don't warp rotors as bad.; I think I can understand the physics - the ceramic doesn't hold any heat, so doesn't cause the heat soak that warps rotor.

 

[Dirtman]

Get tungsten carbide rotors!

 

[Curious Hound]

Get tungsten carbide rotors!

Make your own by recycling the filaments from all those incandescent light bulbs that are being replaced by LED’s.

 

[Dirtman]

Make your own by recycling the filaments from all those incandescent light bulbs that are being replaced by LED’s.

I always wondered if I could sell the dust from grinding tungsten electrodes. I've been welding for 20 some years now and have collected almost a whole salmon egg jar full of it!

 

[85_Ranger4x4]

So, for mall crawlers, get the drilled rotors. For the rest of us, undrilled provide equal or better performance. The high end rotors with directional vanes that pump air thorough the rotors have their place at the track where you get air moving thorough the rotor before the next corner, and drilling may still have a purpose there as it would allow slightly more cooling.

The Ford GT still has drilled rotors, GT-350/500 does not.

But the GT rotor is made out of some funky looking stuff too...

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[Mightyfordranger]

I am learning... Knowing this I'll prolly never buy drilled/slotted again but I wanted to try em and they weren't horrible priced compared to a smooth rotor.

I'll post back up with how I like em if anyone cares to know?

 

[JohnnyO]

Did you explain to her that brakes can catch on fire when they get hot?

I don't think that would happen but if I wash her car right when she gets home steam comes off the wheels.

 

[Dirtman]

I need a mohel.

 

[sheep herder]

I wonder how much a tungsten carbide rotor would weigh.

 

[Dirtman]

I wonder how much a tungsten carbide rotor would weigh.

Less than iron. It's a thermal coating on an iron rotor. The rotor itself is actually thinner because the tungsten carbide is so hard. Watch the video... tungsten carbide is like 1000% harder than cast iron. The coating is like paint, but so hard it lasts longer than a normal rotor. I do this sorta thing with hard facing at work, you weld on super hard material to make a part last longer. But if the part were 100% tungsten carbide for example, it would weigh a ton and shatter on the first bump. So you coat flexible cheap metal in hard crap. Any excavator or bulldozer bucket will have hardface welds on the bottom.

 

[sgtsandman]

I've used drilled and slotted rotors in the past. Good ones too. Braking performance didn't seem to be any better with them. Of course, it may be because of modern materials used in brake pads now. I prefer ceramic pads and have used them for years because of the longer life and less dusting.

That being said, I'm pretty sure the pads on the back of the 2011 are organic. When I replaced the rear rotors and pads last time, I bought the super duty rear pads. I'm pretty sure Rock Auto said they were organic. They also have a flat profile rather than the typical tapered from the face to the back of the pad that most pads have. They tend to have a bit of a braking groan now as a result but they seem to work. Brake dust doesn't seem to be a problem.

In any case, if you buy good rotors, they should work just fine with no problems or cracking. Brake dust will build up in the holes over time. So, you might want to clean those out from time to time. Otherwise, you might as well have standard rotors. Me, I'll just stick with a quality standard rotor anymore.

 

[Mightyfordranger]

"just stick with a quality standard rotor anymore"

What do you get? cause there's an a$$load of em on rockauto. There's coated and non coated and only the non braking surfaces are coated. Learn me.

 

[Dirtman]

I put slotted rotors on my cavalier after warping the factory rotors. Bought from tire rack and can't remember the brand. (Like I said, tons of chinese garbage out there) They lasted less than standard oem or Bendix non slotted rotors. I beat that car to death but what helped was good ceramic pads, not rotors. My fox body brakes on my 65 have always had EBC drilled and slotted rotors so it's hard to judge them since the oem front brakes were drum, but they stop on a dime even with no power assist.


And FYI like @Mightyfordranger said, "coated" rotors have nothing to do with the actual braking surface. It just means they have the non contact surface painted so they don't rust as fast around the hub or in the fins. It's just grey spray paint. I definitely love them but they don't make any difference in stopping.

 

[Mightyfordranger]

I put slotted rotors on my cavalier after warping the factory rotors. Bought from tire rack and can't remember the brand. (Like I said, tons of chinese garbage out there) They lasted less than standard oem or Bendix non slotted rotors. I beat that car to death but what helped was good ceramic pads, not rotors. My fox body brakes on my 65 have always had EBC drilled and slotted rotors so it's hard to judge them since the oem front brakes were drum, but they stop on a dime even with no power assist.


And FYI like @Mightyfordranger said, "coated" rotors have nothing to do with the actual braking surface. It just means they have the non contact surface painted so they don't rust as fast around the hub or in the fins. It's just grey spray paint. I definitely love them but they don't make any difference in stopping.

if you look at rockautos list of rotors they have some that the entire rotor is coated in a black coating. What's that do? Should I post a link?

 

[97RangerXLT]

if you look at rockautos list of rotors they have some that the entire rotor is coated in a black coating. What's that do? Should I post a link?

my guess is that the rotor was coated entirely to simplify the coating process, and once the brakes are put on, the coating is quickly ground off of the braking surface. Hopefully without messing up the pads...


I have a set of drilled / slotted rotors on my Buick Lucerne with ceramic pads. got them off of Rock Auto as well. the rotors were coated with some kind of silver. had them on the car for about 3 years now, the coating has held up well. Braking is much improved over the warped stock rotors that they replaced. Not sure if it is much over a good unwarped rotor though... I paid about 100 or 150 for the set.

AJ