Cross drill vs dimple drill

[napkinthief]

whats the difference?

 

[Todd TCE]

One has a hole passing through the rotor, the other only looks like it has one.

 

[Jason84]

yeah... and they both crack

 

[WHite97RS]

ive had my crossdrilled rotors for 2 years, numerous hardcore scenic mountain drives with lots of braking....no cracks, you buy cheap rotors, you get cheap rotors, as with anything, you pay for what you get.

 

[ahaidet]

What type of driving/ use do you plan on? Street driving, occasional autocross or drag use and drilled rotors or dimpled rotors are fine. If you are looking to do some track day lapping then you might want to look at slotted rotors. Many people buy quality drilled rotors and use them on the street without problem. If you are getting them mainly based off of looks and don't plan on doing any track lapping at a road course drilled or dimpled will be fine. Both work similar in evacuating gasses and pad material. However holes create "stress Risers" where cracks can begin.

Check out Stoptechs website for any technical brake info: lots of good stuff very detailed and easy to understand.

www.stoptech.com (go to technical information and white papers or FAQs)


Also make sure the holes are drilled properly not by some guy who has a drill press. You also want the holes to be in a swept curve design (that follows the shape of the internal vanes) not in straight lines. Straight lines diminish brake performance.

 

[prostreetdsmx1]

we have sold hundreds of rotors just here in the tuners community alone and we have never never once had a complaint about cracking. We also use the cross drilled and slotted on all of our own personal cars.

 

[DSMJim]

People go on all the time about cross drilled rotors cracking because somebody once somewhere on the internet bought $10 ebay cross drills and they did crack. What I love the most is how everybody who says they crack either heard it somewhere or somebody told them about it, but dont have cross drilled rotors never mind acctually had them crack on them.

I have done auto-x with cross drills on various cars and not had them crack. I have smoked two sets of pads easily over one weekend of lapping and the rotors didn't crack. It's just more typical "internet lore" from guys who heard it from a thread on another board where one guy heard about another thread where somebody had a problem...

 

[Jason84]

actually ive cracked wilwoods big rotors.. i know a few others that have to. also seen people crack the brembo crossdrilled/slotted ones and numerous other ones also.

 

[c5chris]

Cross-drilled rotors are said not to be recommended for autocrossing since they are structurally weaker than slotted or regular rotors. I had autocrossed my other car that has cross-drilled and slotted Eradispeed rotors and I had never had a problem with them. I had seen some rotors that had developed hairline cracks emanating from the individual holes of the drilled rotors though, which may be a problem if these cracks coalesce.

Actually I would rather stick with a regular OEM rotor rather than dimpled, slotted or cross-drilled. They are cheaper, and if they happen to warp, I could just replace them easily. Also, they do not eat up brake pads as much. Brake pads had evolved alot that the new ones do not have the problem of gassing up during hard braking, unlike then where you needed slots or holes to expel them.

Cross-drilled and slots look good aesthetically, esp. if you have a big brake system.

 

[Jason84]

i either use powerslots or cheap autozone rotors. depends on the car.

 

[napkinthief]

I will be using these for street driving, my rotors are almost worn down, but they are stock and I am going to want to replace them with something a little bit better. I was thinking slotted, but slotted or drilled all cost the same, so I said why not? I guess I am getting the cross drilled because it seems to be better from reading around than dimple drilled.


Green stuff pads or something else?

 

[c5chris]

I will be using these for street driving, my rotors are almost worn down, but they are stock and I am going to want to replace them with something a little bit better. I was thinking slotted, but slotted or drilled all cost the same, so I said why not? I guess I am getting the cross drilled because it seems to be better from reading around than dimple drilled.


Green stuff pads or something else?

For street driving, get ceramics. They get used up less, does not eat your rotors as bad and leaves less brake dust so your clean wheels look good for weeks.

Green stuff/Hawk/Metal Masters - save it for the track.

 

[Defiant]

People go on all the time about cross drilled rotors cracking because somebody once somewhere on the internet bought $10 ebay cross drills and they did crack.

http://www.dsmtuners.com/forums/showthread.php?t=141849

 

[Jason84]

in my old 1g with 2 piston front calipers i had powerslots all around (DONT GET CROSSDRILLED) and axis metal master pads up front and hawks in the rear.. and that setup was awsome... like 2 days after i put them on a lady pulled out infront of me when i was going 40... lets just say good thing i put the brakes on

 

[DSMJim]

http://www.dsmtuners.com/forums/showthread.php?t=141849

Thats one of 10,000,000 big deal. I guess you should pull out your transfer case because there a chance that same thing will happen to you when it locks up. Your chances of an accident from a transfer case are 1000X what they are from cross drilled rotors. If your taking that chance, then cross drilled rotors won't be a problem for you.

 

[Todd TCE]

Internet lore... ?

From one who sells these for BBKs, I can tell that I strongly discourage it for any use other than daily street driving. Never for the common open track driver. Common? Yes, meaning he's not prepared to change these out on a regular basis when the cracks begin to show.

Street use, autocross use both are not hard on brakes as open track day use is. The problems are far less about rotor strenght than thermal expansion and contraction issues. Doesn't matter the manufacture either. Pick one. I've also personally picked up blown up parts of Porsche rotors off the track at RA to make ready for the next event following a Pcup session...

Are they 'bad'. No, just not as durable as plain parts are. Should you buy them? If you are comfortable with the trade offs; sure. So why do people continue to buy them? Because they like the way the look. So what, there's noting wrong with that.

I think you'll find that every reputable buider/supplier of BBKs will share this same infomation with you. Me, Wilwood, Stoptech.....

All I ask that customers be informed buyers.

 

[Defiant]

Thats one of 10,000,000 big deal. I guess you should pull out your transfer case because there a chance that same thing will happen to you when it locks up. Your chances of an accident from a transfer case are 1000X what they are from cross drilled rotors. If your taking that chance, then cross drilled rotors won't be a problem for you.

Just giving a link. No shots were fired.

 

[cait sith]

People are still debating cross drills?

They're great if you want to have a pretend race car.

 

[napkinthief]

Pretend race cars are cool.

I've decided to go with slotted/cross drilled by Brembo from the speed factor, not a bad deal for 140$. This car is a daily driver, and I will probably never go to the track. I like the way it looks and it makes most cars that have it get a more aggressive look. Isn't that why people convert to 97-99 front bumper? I am sure that bumper doesn't add 7 horsepower.

 

[DSMJim]

Buy whatever you want. I have used them in auto-x crap loads of times and not had a problem. Then again I don't buy them from Ebay or Taiwan so maybe thats why. Going on car number 5 now and set number say 7 with no cracks to date. Each set saw aprox 3-4 sets of hawk pads...

To each their own, I just find the stories all come from guys who heard of somebody else who had a problem, thats Internet Lore where I come from.

Next your all gonna argue the EGT probe MUST be in the manifold, I can see it coming.

 

[prostreetdsmx1]

Next your all gonna argue the EGT probe MUST be in the manifold, I can see it coming.

i thought it went in the upper coolant hose WTF

anyway, the problem is that there are soooooooooo many no name companies on places like E-bay and those rice shops that simply re-box china rotors. I have seen these rotors broken. People have brought them to the shop and when you get a chance to see them they look more like pressed powder. Pretty shitty.

Anyway, if you stick to the names that work and have a rep like Brembo or Centric you have nothing to worry about. I have said it once, I'll say it again. Hundreds of brakes sold, the abuse of our drift cars, our track cars and our street cars and NEVER a single report of cracking.

 

[D_Eclipse9916]

I agree with Martin, I abused the living shit outta my cross-drilled brembo rotors, incidentally I got them from Martin too. Went to the track and on a 25-minute session I totally destroyed my axxis metal masters pads (went up in smoke LITERALLY) but my rotors are completely fine, I was surprised they didnt even warp, my caliper paint (specifically for calipers) went from bright red to black in that one session. I was like holy crap, I will now use brembo only from now on for rotors, but I wont go with axxis again cuz they were destroyed in one track session and started to fade.

Also, brembo would not sell cross-drilled rotors if they cracked. Do you know how much the brembo brand-name is worth? They would not risk their reputation if those rotors cracked, not BY A LONGSHOT! They also come stock on a lot of cars. As with almost anything on a dsm, dont cheap out on parts, theyll come back to get you. I would rather spend cheaply on a new turbo or something along those lines, oh no if it breaks you wont go any faster, if your ####ing brakes go out, you cant stop and almost gaurantees a wreck. Brakes ARE one of the most important parts of your car so please spend the money there before anything else aside from good tire rubber.

 

[Rx3]

People go on all the time about cross drilled rotors cracking because somebody once somewhere on the internet bought $10 ebay cross drills and they did crack. What I love the most is how everybody who says they crack either heard it somewhere or somebody told them about it, but dont have cross drilled rotors never mind acctually had them crack on them.

I have done auto-x with cross drills on various cars and not had them crack. I have smoked two sets of pads easily over one weekend of lapping and the rotors didn't crack. It's just more typical "internet lore" from guys who heard it from a thread on another board where one guy heard about another thread where somebody had a problem...

I would have to disagree. I have a set of BREMBO cross-drilled rotors that have cracks all over them. Matter of fact, they are still in my garage. Would you like to see the pictures?


Daily driven, a season of autocross, 2 track days at the Glen, they lasted just under two years.


If you are just daily driving your car, or auto-crossing only then maybe there isn't a problem. If you take your car to a serious racetrack and don't REGULARLY check/change your rotors as necessary, they will crack. How and when depends on you and your car.


Brembo sells cross-drilled rotors yes. But the responsibility falls on the owner of the car to properly check and replace worn rotors as necessary. Yes race teams may use cross-drilled rotors, to save weight but THEY CHANGE THEM VERY FREQUENTLY. Do not assume that you can just throw on a pair of cross-drilled rotors and forget about them.

 

[D_Eclipse9916]

^^^^^ Very true, but I guess I Was being ignorant in thinking that somebody wouldnt check their rotors and pads everytime they went to the track or AT LEAST every 2-3 months. I am usualyl doing something on my car that requires taking off my wheel at least every 2-3 months so I guess that is natural for me...

 

[flinguist]

I bought into the cross drilled rotor cracking thing too, however over the last year or so I've noticed a lot of high profile cars using them. I've also never read a magazine article, or seen anything on automotive shows about cross drilled rotor problems. I would say unless you absolutely beat the piss out of your car you won't have a problem, if you buy them from a reputable company. If you're that hard on your car you'll probably wreck it, or break something else before you have to worry about cracking your rotors. One thing I can personally vouch for is that cross drilled rotors work really well in wet weather, as opposed to normal ones.