Welcome, Guest. Please login or register.
September 01, 2014, 09:37:18 AM
Pages: [1]   Go Down
  Print  
Author Topic: Insight to slotted and cross drilled rotors  (Read 1617 times)
0 Members and 1 Guest are viewing this topic.
stirfriedferret
New Member
Posts: 173



Reputation Power: 2
stirfriedferret pfffft.
Trade Count: (0)

View Profile
« on: March 12, 2009, 12:39:54 PM »

Taken from http://www.superhonda.com/forum/f93/cro ... rs-304172/ but modified a bit (actually a lot). The guy that originally wrote up the article had many false facts.  I'm taking out the facts that are wrong. You may compare this article to the original as you wish.

Slotted Rotors:



- The slots on the rotor helps clean the brake pad, which improves bite. (not so sure about this)
- Slotted rotors MAY also cause slightly more brake pad wear and tear giving you less miles on a pad before it needs to be replaced. Shorter maintenance schedule.
- Slotted rotors allow gasses between the rotor and pad to vent.
- Slotted rotors are less prone to cracking then the cross drilled rotor.
- Slotted rotors weigh less.
- Slotted rotors have less disc surface than stock, thus reducing your braking ability.
- Slotted rotors maintain around 96% of the friction surface

Drilled Rotors:



- Drilled Rotors are more prone to cracking than slotted.
- Drilled Rotors allow gas to ventilate during brake fade.
- Drilled Rotors reduce unsprung weight (barely) due to their weight reduction.
- Drilled Rotors have less disc surface than stock, thus reducing your braking ability.
- Drilled rotors maintain around 85-93% of the friction surface


Drilled and Slotted Rotors:



- The drilled holes will increase the cooling after braking (under certain conditions which I will explain later).
- Drilled and slotted are the most reliable (under certain conditions, damnit!)
- Drilled and slotted are going to weigh less from the same manufacturer. Other designs might be lighter from company to company.
- Drilled and slotted will give the most performance benefit to acceleration due to less unsprung weight.
- Drilled and slotted will also be the hardest on your brake pad (wear and tear)
- Drilled and slotted only maintain 80-91% of the friction surface.

Alright, here's the section where I will explain everything that I NEED to explain and debunk all of those myths and whatever else questions you have.

Let's begin with the slotted rotors. Slotted rotors WILL, like all of the other types of rotors, give you a performance benefit under certain conditions. Do you see those slots in it? Those slots reduce the surface area of your rotors which reduces your contact surface between your rotors and pads, but at the same time allow gasses that have formed between the rotor and pad to escape.  These gasses are only created during extreme braking conditions such as auto crossing and road racing.  Without those slots, the gasses formed by heat will stay in between the rotor and pad, thus causing heat fade or brake fade. So now, the issue may be "Are these slotted rotors okay for daily driving?."  They are OK for daily driving, BUT you may actually notice a decrease in performance if you have a short commute.

Drilled rotors. Yes, everything they say about cracking on those rotors is true.  They are much more prone to cracking than other types of rotors because their structural integrity is compromised by those holes that look oh so cool. (They look cool to me by the way so don't be offended) The holes, like slots, also reduce the surface area between the rotors and pads.  They also allow gasses to escape between the rotors and pads to escape.  But here comes the tricky part. You know your front vented rotors?  They have vents that are between the front and rear surface of the rotors.  Those vents actually work like a vacuum. As the rotor and wheel rotate, it brings in air from the front of the rotor, pulls it through the rotor, and lets it escape at the center of the rotor near the hub. AWESOME. So they work on a vacuum like stated before. Think about a vacuum cleaner, right. Put holes all over the hose (not literally, your wife or mom might kill you) and what happens to the suction at the end of the vacuum?  Well, that's exactly what happens to rotors when you cross drill them.  So how and when are cross drilled rotors effective?  They're only effective when you have a type of duct or panel that directs air directly to the rotors (they usually come from the lower grill to the inner fender).  The air is then blown THROUGH the cross drilled holes in the rotor. That is the ONLY time that cross drilled rotors are effective.  Otherwise, they are just a waste of money, and they will crack and reduce your braking ability.  So to answer your question; No, they are not recommended for your daily driver.

As for cross drilled and slotted rotors, put both of those summaries together.  Big brake kits fall under the same conditions, except for the fact that they have more surface area.  This surface area will allow you to dissipate more heat under normal driving conditions.

Can you resurface cross drilled/slotted rotors?  Yes, you actually can.  The problem here is whether the manufacturer recommends not resurfacing or not.  All rotors have a machining limit and it can only be measured with an outside micrometer or a rotor micrometer.  Machining beyond your limit will make your rotors more prone to warping due to the lack of rotor mass.  Another thing on resurfacing these types of rotors; if this shop says that it will eat up their bits, they're lying to you.  These slots and holes are actually chamfered or rounded out (IF you have a quality rotor!! Some are just straight cut.).  If they can't resurface these types of rotors, then what about rotors that are warped or have excessive run out or parallelism? The bit isn't always touching the rotor at all times.  It doesn't even do that in the scratch cut! Enough of that.
Bottom line: You CAN resurface slotted/drilled rotors and ALL shops can do it, it's just a matter of whether or not manufacturer allows you to do so and whether or not the holes and slots are chamfered!

More to come on this topic!
Logged

Fenix
Member
Posts: 448



Reputation Power: 4
Fenix pfffft.
Trade Count: (1)

View Profile
« Reply #1 on: March 12, 2009, 01:33:23 PM »

So what about Brembo blanks and the sort? Is it worth it to upgrade from stock rotors to aftermarket non drilled/slotted/drilled&slotted rotors?
Logged


Quote from: timot_one
I'll let you guys know that I can only tolerate so much douchebaggery
timot_one
Farts Dust
Posts: 14431


I act like I own this place, because I do!

Reputation Power: 135
timot_one is a god among men!timot_one is a god among men!timot_one is a god among men!timot_one is a god among men!timot_one is a god among men!timot_one is a god among men!timot_one is a god among men!timot_one is a god among men!timot_one is a god among men!timot_one is a god among men!
Trade Count: (3)

View Profile WWW
« Reply #2 on: March 12, 2009, 03:01:05 PM »

Sounds like that guy added a lot of his own personal opinions to this.  Not exactly factual non-biased information, so I would take this with a HEAVY grain of salt.
Logged

Tim
Quote from: clapton924
I would like to comment that I've noticed the quality of our community going downhill as well.  There is too much room for people to just "hang out" and not contribute anything constructive to our site.  I see way too much immature dick/fart joke bullshitting in the forums.  In the past the members of this community were here to talk about cars and off-topic stuff second. I feel this priority has flip-flopped.
stirfriedferret
New Member
Posts: 173



Reputation Power: 2
stirfriedferret pfffft.
Trade Count: (0)

View Profile
« Reply #3 on: March 13, 2009, 03:09:48 AM »

Quote from: "Fenix"
So what about Brembo blanks and the sort? Is it worth it to upgrade from stock rotors to aftermarket non drilled/slotted/drilled&slotted rotors?

Ah yes, I didn't speak about blank rotors here, but I believe that it is worth it to upgrade to better blanks. Usually blank rotor upgrades, such as Brembo, are made to be much stronger than stock (I don't know exactly how) which make them less prone to cracking and warping.  As a result, upgraded blank rotors will last much longer than stock rotors in my opinion. And like I said in the first post, slotted rotors are OK for daily driving but are only really worth it if being used on the track or under extreme conditions.


Quote from: "timot_one"
Sounds like that guy added a lot of his own personal opinions to this. Not exactly factual non-biased information, so I would take this with a HEAVY grain of salt.

Yes, he did which is why I removed all of the items I KNEW were opinions and not facts.  Everything on there is a fact other than those which I stated otherwise.
Logged

thisaznboi88
Member
Posts: 1629


Reputation Power: 18
thisaznboi88 pfffft.
Trade Count: (6)

View Profile
« Reply #4 on: April 13, 2009, 02:36:12 AM »

FYI Brembo are now going to be made in CHINA, they are made in Brazil currently for some of the rotor. Sigh... No more germany made rotors, WHY!!!
Logged

BOOOO!!

AV6NHBP6SPD
Member
Posts: 1909


Reputation Power: 21
AV6NHBP6SPD who is this guy?AV6NHBP6SPD who is this guy?
Trade Count: (0)

View Profile WWW
« Reply #5 on: May 12, 2009, 11:08:15 AM »

Those vents actually work like a vacuum. As the rotor and wheel rotate, it brings in air from the front of the rotor, pulls it through the rotor, and lets it escape at the center of the rotor near the hub. AWESOME

obviously not true
somebody wrote this without knowledge of phisics

take a plate or whatever and put water in middle, then rotate it, where will water go? now try to put water on edge. where does water go, inside? hell no


just read article about this in street machine magazine, they have little more credibility then guy on superhonda forum

facts. drilled rotors were needed in days when pads were made with asbestor and needed to vent gases. today thats not needed, just for looks.
drilling doesnt help cooling(air doesnt go through holes anyway).  drilled decreases cooling becouse you taking mass away from rotors. and yeah it makes it lighter but with negative effect. so sloted rotors are more then enough to vent any gasses if there are any.

ill try to find full article
Logged

Misha
http://www.detailedimage.com/wax.php?id=10288&url=detailedimage.com
"Speed has never killed anyone, suddenly becoming stationary… That’s what gets you" - Jeremy Clarkson
Mike
Farts Dust
Posts: 10745


Fan Boys Anonymous

Reputation Power: 94
Mike is a pimp among pimps!Mike is a pimp among pimps!Mike is a pimp among pimps!Mike is a pimp among pimps!Mike is a pimp among pimps!Mike is a pimp among pimps!Mike is a pimp among pimps!Mike is a pimp among pimps!Mike is a pimp among pimps!
Trade Count: (5)

View Profile WWW
« Reply #6 on: May 12, 2009, 11:28:08 AM »

Good information...
Logged

Fenix
Member
Posts: 448



Reputation Power: 4
Fenix pfffft.
Trade Count: (1)

View Profile
« Reply #7 on: May 19, 2009, 11:36:54 AM »

So whats the purpose of the braided brake lines?
Logged


Quote from: timot_one
I'll let you guys know that I can only tolerate so much douchebaggery
Icebox
Member
Posts: 1180



Reputation Power: 12
Icebox pfffft.
Trade Count: (1)

View Profile
« Reply #8 on: May 19, 2009, 12:00:10 PM »

steel brake lines dont buldge like the stock ruber lines thus allowing the fluid to move more consistently to ur calipers. thus better braking power.
Logged

David - MDVACM Squad #13

My EliteCM Profile
Pages: [1]   Go Up
  Print  
 
Jump to:  

TinyPortal © 2005-2012