Slotted vs. drilled

[sketchyd]

So I understand the reasons behind slotted and drilled rotors, but not the differences (if any?) between the two. To met it seems just looks between slits, holes our both combined. Maybe someone can enlighten me?

I'm doing 4 wheel brakes on my ///M soon, going with stoptech slotted rotors, and after reading the thread on their street performance pads, they're in the mix with pbr/axxis pads.

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[az3579]

Slotted generally is better from a reliability standpoint.

Drilled rotors are known to have the potential for cracking under track use. It also makes a difference if it's cross drilled or cast drilled. Cast I believe is more durable, but still carries the risk.

With slotted, you have more surface area, which is better for cooking. There are no holes that would otherwise compromise the integrity of the rotor.

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[Avetiso]

But drilled looks so :drool

[sketchyd]

Slotted generally is better from a reliability standpoint.

Drilled rotors are known to have the potential for cracking under track use. It also makes a difference if it's cross drilled or cast drilled. Cast I believe is more durable, but still carries the risk.

With slotted, you have more surface area, which is better for cooking. There are no holes that would otherwise compromise the integrity of the rotor.

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I want going to mention it, to see if it came up. I havent heard "prone" but all stories of cracking I have heard were of cross drilled. So that reassures me somewhat. Mostly what I had guessed.

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[az3579]

I want going to mention it, to see. I havent heard "prone" but all spirits if cracking I had heard were of cross drilled. So that treasure me somewhat. Mostly what I had guessed.

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Wow, I really can't read through that autocorrect. Lol

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[Avetiso]

Wow, I really can't read through that autocorrect. Lol

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X2 I think he's trying to communicate.

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[330i ZHP]

what the H

[330i ZHP]

btw - slotted (I have had both and found the slotted to perform better)

[static667]

In my opinion, slotted will give you better reliability. I've been told by several SCCA driver/car owners that cross drilled are nice for the brake gas relief (big cause of brake fade) and reduction of weight but, they warp and crack easily as well as increase the wear on your brake pads. Slotted rotors will get you nearly the same amount of brake gas diffusion without reduced issue of warping, cracking, and pad wear.

[sketchyd]

Whoops, fixt :o

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[330i ZHP]

I will mention that the Brembo BBK 380mm that were crossdrilled warped - an awful shudder when braking

[Vas]

Stasis states that "Crescent slots provide gas relief and pad cleaning while minimizing the pedal pulsations normally associated with straight-slotted rotors or cracking issues common with cross-drilled rotors."

[sketchyd]

Sounds good to me. Personally I like the look of slotted better anyway.

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[az3579]

Stasis states that "Crescent slots provide gas relief and pad cleaning while minimizing the pedal pulsations normally associated with straight-slotted rotors or cracking issues common with cross-drilled rotors."

What is this "pulsations"? I can't say I know what this person means by that.
If it's in regards to vibrations, I didn't have any issues with vibrations or "pulating" until my rotors got well below minimum spec (like they are now). Mine are slotted.

[Vas]

Pedal pulsation is when pads get overheated and the overheated pad is pressed against the rotor. Brake pad material is transferred into the rotor at the molecular level, and then there's a spot with different thermal expansion than the rest of the rotor.

Often mistake for warped rotors.

[M0nk3y]

Pedal pulsation is when pads get overheated and the overheated pad is pressed against the rotor. Brake pad material is transferred into the rotor at the molecular level, and then there's a spot with different thermal expansion than the rest of the rotor.

Often mistake for warped rotors.

BINGO.

Can I vote for blank rotors?

I have drilled by OEM, and personally they are garbage. The drilled holes are always clogged with dust either from track days or autocross. I dont remember when they were replaced, but after 10k miles hard driven (most of the time) they need replaced

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[Vas]

Blanks are the way too go.

[danewilson77]

Blanks are the way too go.

Unless you daily drive and like the aesthetics of the BMW Performance cross drilled rotors.

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[Vas]

Good point Dane. Plus those rotors are a 2 piece design so less rotational mass. However pad life is reduced with them.

[az3579]

Pedal pulsation is when pads get overheated and the overheated pad is pressed against the rotor. Brake pad material is transferred into the rotor at the molecular level, and then there's a spot with different thermal expansion than the rest of the rotor.

Often mistake for warped rotors.

Ah, the very thing I avoid doing at all costs coming off a track session. Didn't realize that had a name. lol
Thanks.


Unless you daily drive and like the aesthetics of the BMW Performance cross drilled rotors.

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Might I add that they are semi-floating and cast drilled, not cross drilled. :thumbsup

[danewilson77]

Ah, the very thing I avoid doing at all costs coming off a track session. Didn't realize that had a name. lol
Thanks.



Might I add that they are semi-floating and cast drilled, not cross drilled. :thumbsup

Sure. Feel free.

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[BCS_ZHP]

Unless you guys are tracking your cars, and obviously some of you definitely are, slotted, drilled, or S&D rotors are pure street bling. I'm fully aware of that and have blinged every one of our "street only" cars. For non-track addicts, any of the non-blank rotors will help your harder ceramic pads on initial bite, however they are terrible on dissipating heat if you're into heavy braking events.

[az3579]

Blanks are hands-down the best rotors to buy for street-only driven cars.

Bruce,
They're actually not terrible on the track. I'd bet you that if I put a set of blanks of my car with my Hawk HP+ pads, I wouldn't get fade.

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[M0nk3y]

If I could get blank rotors, I would.

My rotors have turned blue before. If you guys know what that means, that means I'm overheating the rotors. They don't "dissipate" heat like people think.

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[BCS_ZHP]

Blanks are hands-down the best rotors to buy for street-only driven cars.

Bruce,
They're actually not terrible on the track. I'd bet you that if I put a set of blanks of my car with my Hawk HP+ pads, I wouldn't get fade.

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BP,
The ceramic pads for low dust need S, D, or S&D rotors for initial bite to perform as well as OEM, they don't appear to grab as well on blank rotors. What I meant was these ceramic pads will fade quickly with heavy use, not the solid blank rotors. I've read a lot on the benefits of each of the different rotors but since we don't track our cars, the rotors on the cars at my house are purely to help those low dust ceramic pads get their initial bite and then there's the bling effect which we like.
Bruce

[az3579]

Gotcha. Misunderstood.

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[johnrando]

I went with cross drilled, but it's my daily driver of only 8K miles/year and I don't track. Really like the way drilled looks over slotted.

http://i1214.photobucket.com/albums/cc481/johnrando/IMG_20130525_135215_663_zps1dd1da94.jpg (http://s1214.photobucket.com/user/johnrando/media/IMG_20130525_135215_663_zps1dd1da94.jpg.html)

[danewilson77]

I went with cross drilled, but it's my daily driver of only 8K miles/year and I don't track. Really like the way drilled looks over slotted.

http://i1214.photobucket.com/albums/cc481/johnrando/IMG_20130525_135215_663_zps1dd1da94.jpg (http://s1214.photobucket.com/user/johnrando/media/IMG_20130525_135215_663_zps1dd1da94.jpg.html)

Now we're talking!

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[Smilez]

sexy :D

I've been running drilled/slotted forever. Never had issue, but i dont take her to the track either.

[danewilson77]

sexy :D

I've been running drilled/slotted forever. Never had issue, but i dont take her to the track either.

Holy shit. Is that Ray? Whaddya say?

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[Smilez]

lol. Danney boy. Just been hiding. i log on almost everyday. i read. but never post.

[danewilson77]

lol. Danney boy. Just been hiding. i log on almost everyday. i read. but never post.

Ok brutha. We miss you around heya.

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[BCS_ZHP]

How's that little one treating you Ray? Keeping your hands (and heart) full I bet.

[Smilez]

Oh definitely. Been a blessing. Oh boy shes going to give me more than terrible 2's, but shes a joy to be around with. She has me rolling everyday.

[prowlerflyer]

On a trivia tangent, the Formula Ford guys drill the heck out of their rotors to reduce unsprung weight. In fact on some of the faster circuits, they will also run non-ventilated rotors also for weight, since for the most part they are over braked.

As mentioned the best braking is via blank rotors, an exception being wet braking. Slotted or drilled are superior in the wet for gas/vapor displacement. Think of it as a slick tire vs a treaded one.

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[derbo]

On a trivia tangent, the Formula Ford guys drill the heck out of their rotors to reduce unsprung weight. In fact on some of the faster circuits, they will also run non-ventilated rotors also for weight, since for the most part they are over braked.

As mentioned the best braking is via blank rotors, an exception being wet braking. Slotted or drilled are superior in the wet for gas/vapor displacement. Think of it as a slick tire vs a treaded one.

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For Formula guys where weight is important, the rotors just need to last one race. We on the other hand, expect it to last awhile.


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[prowlerflyer]

That's why it was trivia.... not recommend for street use. We were getting 2 weekends out of non-vented front rotors and around 5 on rears, with a Swift chassis

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[sketchyd]

BP,
The ceramic pads for low dust need S, D, or S&D rotors for initial bite to perform as well as OEM, they don't appear to grab as well on blank rotors. What I meant was these ceramic pads will fade quickly with heavy use, not the solid blank rotors. I've read a lot on the benefits of each of the different rotors but since we don't track our cars, the rotors on the cars at my house are purely to help those low dust ceramic pads get their initial bite and then there's the bling effect which we like.
Bruce

I've been pondering this.. Is this because "low dust " pads go directly to a gaseous state, and don't really grind off to form dust?
Thats my theory anyway, and I like it. Lol.


If I could get blank rotors, I would.

My rotors have turned blue before. If you guys know what that means, that means I'm overheating the rotors. They don't "dissipate" heat like people think.

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I was under thr impression the slots were for gasses, not heat dissipation..

I can see drilling for the weight savings only in formula racing where that little bit really turns out to be really important.

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[derbo]

But I do have a few sets of the BMW performance rotors laying around. Hmmm


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[johnrando]

Are they BMW Perf cross drilled? Good condition? I might be interested in buying a set off you.

[trancenation]

Are they BMW Perf cross drilled? Good condition? I might be interested in buying a set off you.

+1 if you have any brand new sets that you would like to get rid of, please let me know!

[derbo]

Are they BMW Perf cross drilled? Good condition? I might be interested in buying a set off you.

BMW Perf is cross drilled.

http://www.zhpmafia.com/forums/attachment.php?attachmentid=3816&d=1334907889


But as far as condition goes, yes...it's brand new. I stocked up when I got my ECS 135i Brake Kit
https://lh6.googleusercontent.com/-DESUMxItG9Y/TolYbHTkp-I/AAAAAAAAB3Q/FQKsasBmV1Q/w1089-h614-no/2011-10-02_15-12-23_189.jpg

[Avetiso]

BMW Perf is cross drilled.

http://www.zhpmafia.com/forums/attachment.php?attachmentid=3816&d=1334907889


But as far as condition goes, yes...it's brand new. I stocked up when I got my ECS 135i Brake Kit
https://lh6.googleusercontent.com/-DESUMxItG9Y/TolYbHTkp-I/AAAAAAAAB3Q/FQKsasBmV1Q/w1089-h614-no/2011-10-02_15-12-23_189.jpg

I'm in third. If there is a full set left for me, I'm interested.

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[trancenation]

BMW Perf is cross drilled.

http://www.zhpmafia.com/forums/attachment.php?attachmentid=3816&d=1334907889


But as far as condition goes, yes...it's brand new. I stocked up when I got my ECS 135i Brake Kit
https://lh6.googleusercontent.com/-DESUMxItG9Y/TolYbHTkp-I/AAAAAAAAB3Q/FQKsasBmV1Q/w1089-h614-no/2011-10-02_15-12-23_189.jpg

Thats awesome. If you do plan to sell, I'm only a dozen blocks away! Haha.

[az3579]

FYI, ECS Tuning still sells these...

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[derbo]

FYI, ECS Tuning still sells these...

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Course but I wouldn't charge arm n leg like they are.


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[az3579]

Edit: never mind. Don't know why I can't delete my own post on Tapatalk.

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