[Ray]

From what I heard in the past, drilled variations of an OE sized rotor lose their structural integrity, therefore stress or crack between each hole.

Drilled rotors seen on brake kits or race cars have holes that are strategically positioned to maintain strength and improve performance.

[judec]

SLOTTED!!!

drilled rotors were used in rally cars long time ago just because they were able to release gas coming from old composition pads under extreme circumstances. The pad composite changed long time ago, no need for venting holes. The only reason for their usage recently is in cars on tracks (means road course) with lot of braking from high speed, where they need larger diameter rotors (for less fade) but also need to lower unsprug weight, there comes the drilling. But in F1 cars when the brakes dont fall apart immediately after crossing the finish line, the team fires their chief engineer for oversizing the rotors, so take it that way
Also there's no relevant relation between holes and better cooling If U dont believe, try to use wikipedia+google+some brain. If google is not your friend, try to use this address and read carefully:
http://www.carbibles.com/brake_bible.html

For all of U kids - there is a big difference between "I think" and "I know". Please weight your words B4 U release them out of your mouth/puter.

[ADHD]

Originally Posted by judec

SLOTTED!!!

drilled rotors were used in rally cars long time ago just because they were able to release gas coming from old composition pads under extreme circumstances. The pad composite changed long time ago, no need for venting holes. The only reason for their usage recently is in cars on tracks (means road course) with lot of braking from high speed, where they need larger diameter rotors (for less fade) but also need to lower unsprug weight, there comes the drilling. But in F1 cars when the brakes dont fall apart immediately after crossing the finish line, the team fires their chief engineer for oversizing the rotors, so take it that way
Also there's no relevant relation between holes and better cooling If U dont believe, try to use wikipedia+google+some brain. If google is not your friend, try to use this address and read carefully:
http://www.carbibles.com/brake_bible.html

For all of U kids - there is a big difference between "I think" and "I know". Please weight your words B4 U release them out of your mouth/puter.

So where does your EXPERIENCE Come from??? Is this your opinon or where did u get these facts???
Im sorry but SHEERSPEED is a Formula renalt driver so his opinon is "I KNOW" not "I think" so maybe u need to think before u talk next time!!

[jetblk328i]

yea i dont think that guy knows what hes talking about.....sure they last shorter times but they def. have better cooling....

[ScheerSpeed]

alright, alright, calm down....

by the way, F1 crew cheifs dont get fired if the brakes dont fall apart. i was a guest of Juan Pablo Montoya in '04 at the USGP, and i got to sit in the williams car, look up close and everything. the brakes are drilled.

in reference to Judec's comment, all you are saying is good thigs about drilled rotors, like weight, heat dissipation, etc.

it is common sense that by having less mass, it wont take as long to cool down (drilled rotors)

try driving a formula renault car at 180 at cali speedway and braking to 45 in a matter of a few feet to make the first corner of the infeild, then come tell me drilled doesnt make a difference....

[IND-Distribution]

Drilled rotors are unsafe and do not increase performance.

[Hunter399]

Originally Posted by judec

SLOTTED!!!

drilled rotors were used in rally cars long time ago just because they were able to release gas coming from old composition pads under extreme circumstances. The pad composite changed long time ago, no need for venting holes. The only reason for their usage recently is in cars on tracks (means road course) with lot of braking from high speed, where they need larger diameter rotors (for less fade) but also need to lower unsprug weight, there comes the drilling. But in F1 cars when the brakes dont fall apart immediately after crossing the finish line, the team fires their chief engineer for oversizing the rotors, so take it that way
Also there's no relevant relation between holes and better cooling If U dont believe, try to use wikipedia+google+some brain. If google is not your friend, try to use this address and read carefully:
http://www.carbibles.com/brake_bible.html

For all of U kids - there is a big difference between "I think" and "I know". Please weight your words B4 U release them out of your mouth/puter.

Nice link!

[Ron@Modbargains]

Do I dare jump into this thread??? .....here goes.

Lets see I've had this argument in the **********s office about 20x last year or so, so we kept going to all these different sources for information. Eventually after sifting through everything, I'll break it down as simply as possible. Even addressing what I've just read in this thread seems like the typical thread I've read on many forums.

Cross-Drilled -Out performs slotted - False. Best Performance on the Street- Yes one could easily make that argument. I'll get into it.

Cracks- easier with Drilled - Not necessarily, since you wanted personal experience (I've cracked every type of rotor even blanks, and yes some serious cracks) Multiple factors contribute to cracks - the main reason being that the rotors are worn down. Stress fractures are still ok to have on your rotor it doesn't mean its bad yet, but if the fracture/crack is going from one hole to the other hole then now you're in need of replacing the rotor, same if the crack travels to the edge. Other contributing factors are the brake fluids used, and the heat cycles that the rotors go through. Each rotor has different ratings, hard to say this right now cause there are BBK rotors and replacement rotors which are different. A replacement rotor is typically cross drilled right through - that is not the proper way for a cross drilled rotor to be made, it should be cross drilled mathematically in proper areas both sides of the rotor being completely different actually - you'll see this on the BBK's from any of the major companies. short answer - debunked myth/with slight truth in it.

Cooling is better with the Cross-Drilled- does it dissipate heat quicker - Yes which helps performance somewhat - but who here is driving on some serious track races and needs that type of cooling? Your brake fluids you guys use is going to be more important down the line. Anyway short answer - yes helps cooling.

Cross Drilled Rotors- eat up at the brake pads quicker acting like a shredder- sorry not true, I believed that one cause it seemed to make sense. That it gave an uneven wear on the pads. The reality is it doesn't eat up the pads any quicker, if anything they last longer, meaning they are actually the street pad most would want. Short answer - they are fine on the pads.

Cross Drilled - are better in the rain - I remember reading about the answer being true - I don't remember the reasons but the water passes escapes through the holes.

Cross Drilled - less weight - reality the weight difference is negligible. No this don't really matter on the weight, you can save more some where else. Don't do it on your brakes!!!

Slotted - Better for performance- yes this is true. Reasons being is that each time the pad goes through the slate of the rotor, its cleaning the pad one more time through. Its giving a clean swipe on the pads each time.

Hence this cause's - Pad wear down much quicker. Cross-drilled wins between the two in the longevity on pads, hence making them better for street. But Slotted perform better making them better for the track/performance.

Looks - well this is subjective. So you can all have your own opinions on this. But Cross drilled wins on looks in my opinion - I like the way it looks for the street.

Cross- drilled - Street Choice
Slotted - the Track choice

Now to debunk some statements made on here.

Originally Posted by ScheerSpeed

alright, alright, calm down....

by the way, F1 crew cheifs dont get fired if the brakes dont fall apart. i was a guest of Juan Pablo Montoya in '04 at the USGP, and i got to sit in the williams car, look up close and everything. the brakes are drilled.

in reference to Judec's comment, all you are saying is good thigs about drilled rotors, like weight, heat dissipation, etc.

.....

Asked this question of Brembo is the only real brake company out there for the F1 - Reason for it is certain race teams want to experiment with different rotors/ for different settings. In the end the majority more then 75% all use slotted. Brembo indulges them in the experiments, some for rain purposes, and to gather data by different race teams, plus other various reasons each team has. But slotted is the choice on the track and what is proven to work. - Please no one starting bringing up the Ferrai Enzo or other super cars with the cross drilled -I asked this as well -Answer: Looks, its not unsafe and they know the person buying that car is rightly concerned with the looks being of major importance. The other reason is those buyers are driving a car built for the street.

Originally Posted by ilia@industry

Drilled rotors are unsafe and do not increase performance.

Where is this bold statement coming from?? No drilled rotors are safe and used by Porsches, Ferraris etc in their OEM rotors. There are increased benefits from uising Drilled rotors as mentioned above.

Originally Posted by ADHD

I say DRILLED are FAR SUPERIOR to SLOTTED IN PERFORMANCE!!
1. Drilled will stay cooler yet they dont last as long cuase they crack yet the perfomace is better cause they stay cooler
2. Drilled are used in F1, NASCAR ETC... So why are all u saying SLotted are better???

I want Info from PERSONAL EXPERIENCES Not A manufacturs suggestions!!

Yes, you are right say they stay cooler. But the cracking again is not the main issue. NASCAR uses slotted on their vehicles that are actually racing(not talking about their show cars), I am wondering why people seem to not notice this.

Originally Posted by DTMhunter

"Each and every Dinan/Brembo brake conversion is now available with not only a choice of black or red calipers, but now you can choose either SLOTTED or DRILLED rotors! Dinan's preference remains going with the slotted option, but now YOU have the choice."

There is a reason these companies dont want to sell into distribution like how most vendors get them and just sell without being informed. It's mis-information that non-direct vendors end up generating. Reasons for both is again to give the proper the choices based on each customer's driving styles/abilities/purposes and matching him up accordingly.

My 2 cents into your discussion. Again welcome to ask me any brake question or discussion you may have in terms of replacment brakes or Big Brake Kits. We carry replacment brake rotors from Stoptech/Brembos, multitude of different pads, BBK's from Stoptech/Brembo/Wilwood, not all of our stuff is up on the site but I'll be working on getting it up there for you guys in the coming months.

[judec]

well OK, I'm 33 so I'm past my age of rebellion. Apart from my personal experiences I read a lot the think about what I've read. It looks like U don't, but nevermind. Ron just spent some serious time to give U some explanation. I just answered the subject of this thread and voted in the poll + stated my opinion and provided some proofs and facts. Shouting "drilled is superior" isn't enough, I'm sorry. Show me a similar effort and we can talk. Until then it's a dog barf.

It is likely U wont believe me or wont believe Ron, it is also likely U won't believe anybody saying what U dont like, but who cares? Learn or die stupid, I dont care. But one advice for the non-believers - if U dont race and dont know any racer or anyone from a racer crew and U dont read for any reason or U do but U just dont believe what U read, just go to some road course track and take a walk around when there will be no cars. I bet U'll be able to find a few drilled pieces outside of some heavy breaking corners. Then tell me they are superior.

Also I tried to not bash drilled rotors completely. They were created for a reason and are used now frequently for another reason. But U can't call them superior w/o explaining for what application are they superior. If U do, U're just presenting your lack of knowledge. And supporting your statement by saying that they are beter because U have slotted brembos installed on your car or they are better because all your ricer friends use them and U've seen it in a tuning magasine only causes LMAO.

So - if you NEED large diameter rotors for your extreme braking on the track, drilled is the way to go because of lower weight, but U have to sacrifice longevity, U have to count with that. If U dont need such a large diameter rotor, go with slotted. much better for daily driver + more efficient and lasts longer.

[wrickem]

My Porsche came with drilled and they are the best brakes on any car that I've ever driven. One PITA thing is when you wash the wheels, the water stays in the holes and when you drive it, it looks like someone flung shit in your clean wheels.

[DTMhunter]

Nicely said Ron!

[ksfrogman]

I'm not a race car driver, and imagine not too many of us are, but from all the vendors I have spoken with (including Dinan), slotted are actually preferable. I have cross drilled, because they do look much better.


From http://www.rimier.com/eshop/item.php...449&cat=490954

Cross Drilled Rotors vs Slotted Rotors

Rotors with drilled holes or slots can significantly improve braking performance. The drilled holes or slots continuously refresh the brake pad surface area and also provide pathways to help disperse built-up gasses and heat that result from pads acting on the rotors during the braking process.



Slots or holes help deflect water in wet conditions and improve brake performance. The effect is more noticeable on cross-drilled rotors because of the different ratio of the surface area used for braking. There is also the possibility that water will flow through the holes of a vented rotor into the vane gap - although you maybe going for a swim before this happens.



Where friction levels of an extreme nature are required such as on the track, Brembo slotted rotors are the preferred solution. The mechanical friction resistance of the Brembo slotted rotor is high and. all of Brembo’s slotted rotors are directional in construction.

EDIT: I just noticed Ron's explanation, which makes a lot of sense.

[S4to335]

I have alcons..and they are sorta both...small c-shaped slots.

[DTMhunter]

Nice brakes!

Alcons makes a VERY nice system

[HyperM3]

What people are overlooking is the fact that the PAD actually has the biggest effect on braking, not the rotors. Maybe about 1% of the people on this forum will take their cars to the track and run it hard enough to feel the difference between flatface rotors and drilled/slotted.

I auto-x'd my M3 for many years and put on drilled rotors with race performance pads. Sure, they looked cool but they never got hot enough to actually work perfectly. During colder days on the street, you had to lay into the brakes to get the pads to make the car stop. Once they were warmed up though, they bit like hell.

When it came time to replace my rotors, I just went back to the OEM flatface though but kept more street friendly race pads. They brake just as well if not better and I dont notice any fade no matter how hard I drive.

Its all for looks when going for slotted/drilled rotors because nobody will really take advantage of what they are made for. Dont even get me started about BBK's.

Good pads, braided lines and top shelf brake fluid will make all the difference at about 1/3 the price.

[ADHD]

hmmmmm wow i need to start reading!!! Cliffnotes anyone???

[sg335]

I have been through this argument many times before. I will only comment on my personal opinion based on real track experience with all types of rotors on stock and BBK equiped cars (Solid, Floating, Slotted, and Drilled (or Cast Holes whick is a completely different and superior method of creating holes without stress) and say that Slotted or solid faces are better for heavy track use unless your brakes are still too hot and you cannot go to a larger rotor, in which case drilled may provide a small increase in heat shedding. What hasn't been discussed is the design of the rotor, specifically the center portion that seperates the two halfs. It is within this region and its various designs by each manufacturer that produces over 99% of the cooling of the disk itself. Vein design is highly debated amongst manufacturers. StopTech goes one step further and vents directionally thier pad retainer on top of the caliper to further increase the efficiency of heat disipation of the rotor. Some rotors are not directional. So the left and right rotors are vented in opposite directions and one side of the car's rotors will run significantly hotter than the other. Some less expensive stock replacement drilled rotors are actually not vented in the middle and only a single piece design.

For the street, it doesn't matter and most prefer the looks of cross drilled. I personally prefer the look of slotted. Before I would look to drilled for extra heat loss, I would also as mentioned upgrade to a better brake fluid like RBF600 and run a better pad with a higher functional operating temperature. Most stock or street pads loose their efficiency in the 500 - 700 degree range. A good multipurpose street/race pad operates well up to 900 degrees and a race pad holds efficiency until 1,100 degrees or above, but do not work well on the street as they never get up to operating temperature and can be hazardous on the road.

Always fun to read these brake threads

[Don Nguyen]

I am glad Ron wrote all of that, so I didn't have to, haha.

-Don

[Mr. 5]

I like the drilled because they are usually lighter and they look cool.
I'll say though that I believe the slotted is better for tracking.

[Ron@Modbargains]

Don I go off on brakes/suspension all the time at the office haha

sg335 -your right there are quite a bit of different designs out there with the vanes of the holes. All important factors. Again thats in BBK category if anyone wants to talk about that both Don and I can definietley help anyone interested in BBK's.

What's interesting is bmw's new performance rotors, they have cross drilled in slotted format! Thats a pretty interesting design thats for sure, I wonder if we'll see other manufacturers jump into making it - I would love to see some testing on that design.

[E36325is]

I'd go for slotted, my cross drilled rotors came with my Boxster are now warped after just 1 track day.....

[Max_!]

The only reason to have drilled or slotted rotors today is for looks.

The holes mean less mass and less internal vanes which means less surface area which means they overheat faster and cool down slower. Which means you need to make them bigger, which means they weigh more.

For a road car, you want solid discs with grooved pads. For the same material, these will outperform drilled or slotted rotors under any condition.