Looking for some info one which is better, last longer etc. Drilled or slotted rotors. I would welcome some pics of any if someone has it. Any additional info would be great. I know there are some big brake kits out there, but now I am just looking for some slotted or drilled rotors to upgrade.... any thoughts? Also, can you put larger rotors with the stock brake system?

 

I've always heard that slotted were a better compromise between cooling and stopping power (because of increased surface area. The drilled ones sure do look cool, though, and would probably be fine for the street if you're more concerned with the look than the peformance benefit. I'm no expert, though. JR

 

Drilled tend to crack, heat stress along the hole edges leads to damage. Few drilled rotors avoid this issue... only the high end ones with cast in holes do not suffer from it.

Slotted is your best bet, or partial drilled such as the EBC rotors have (aka dimpled)

 

Rotors-Better? Last Longer? you get what you pay for. Cheaper rotors would be more prone to overheating and cracks if drilled even if cast with holes. You have to be careful and over time you should expect wear and tear on drilled rotors. Slotted rotors work and resist trouble from heat better. If you can afford it, I like Powerslot rotors for autocross or track but they are not required.

For street driving you do not need to replace rotors. Maybe just the brake pads if you like.
You do not need larger rotors.

If you want better performance think rotors and brake pads and replace the stock brake fluid while you are at it.
Unless you are on the track and have way too much power/money forget the big brake kits.

If you upgrade brakes always remember to upgrade the rears too.

Here are Zimmerman cross drilled rotors in the rear


Here are Zimmerman cross drilled and slotted rotor front

 

I have 35,000 miles since July of 02, and have done 17 track events, including six multi-day Driver Education with BMW and Porsche clubs and four or five open track (lapping) days with smaller groups. I wore out two sets of stock rotors; I had gone to higher temp brake fluid, steel lines, and upgraded pads (Ferodos) for tarck use and now use them for everyday driving as well. I replaced the front rotors with Helix slotted rotors - these are stock rotors with the slots cut in them. I did this to maximize braking 'feel', and to help deal with brake fade on track days. The stock system got mushy and ineffective after ten or so laps at a 2 miles track. (They were OK in the next session.)
I expect to wear out the pads after about six-ten days on track, so I have a spare set for the fronts. I will be doing about 17 events between now and October. The rear (stock) pads lasted twice as long, so they are fine for what I do, though using something like Green Stuff pads would be cleaner. The rotors will about the same as stock.
For street driving, if you want to get a better look, it won't matter what you do. For performance, racing rotors are usually slotted. You can upgrade your pads for a reasonable cost and the 'feel' will give a little better bite. Good luck and enjoy!

 

Thanks for all the advice. I love the look of drilled rotors. As for the cracking issue with drilled... how many miles roughly before they crack are we talking?

As for brake pad upgrade... which is the best in terms of brake dust.... I clean my wheels what feels like every day.

Thanks again for the info. This has been very helpful!!

 

>>Thanks for all the advice. I love the look of drilled rotors. As for the cracking issue with drilled... how many miles roughly before they crack are we talking?
>>
>>As for brake pad upgrade... which is the best in terms of brake dust.... I clean my wheels what feels like every day.
>>
>>Thanks again for the info. This has been very helpful!!

Cracking isn't going to be caused by mileage. It's going to be caused by extream heat cycles. If you are using drilled rotors on your street car I woundn't worry about cracking, you proabably won't see it. Even for Autocross you probably won't see it. Only if you do alot of track day's where you run multiple laps and generate maximum heat in your brakes.

 

Take a look at the Brembo "Sport Slotted" rotors at Tire Rack.
Jim

 

>>>>Thanks for all the advice. I love the look of drilled rotors. As for the cracking issue with drilled... how many miles roughly before they crack are we talking?

Not a function of miles. read below.

>>>>As for brake pad upgrade... which is the best in terms of brake dust.... I clean my wheels what feels like every day.

Brake dust is a separate issue. Lower dust- try EBC green pads or Mintex Redbox (not as low as EBC but probably better street performance and lower chance for squeaking). Performance of street pads is best with low temperatures and track pads are best at higher temps (not very good at low temps so not good for street use).

>>Cracking isn't going to be caused by mileage. It's going to be caused by extream heat cycles. If you are using drilled rotors on your street car I woundn't worry about cracking, you proabably won't see it. Even for Autocross you probably won't see it. Only if you do alot of track day's where you run multiple laps and generate maximum heat in your brakes.
>>
An example of cracks in a drilled rotor
with explanation text on a Mazda RX-7:

Crack through drilled hole in brake rotor.

"This all began with my switch from stock rotors to X-drilled rotors. I had initially gone to the track with my stock rotors and a set of Hawk Blue (9012) racing brake pads. This was a perfectly adequate braking setup for me as a beginner running approximately stock horsepower. The Hawk Blue pads are like boat anchors and I could engage the ABS at speeds approaching 100mph. Then I happened upon a set of front X-drilled brake rotors. They were in good condition, inexpensive, and looked nice on the car. I matched these with a pair for the rear. Well the gist of this tale is that after FIVE days on the track the front brake rotors exhibited those telltale signs of premature cracking and after only THREE days on the track the rear Xdrilled rotors had cracked to failure."

"How did I know? The brake pedal was vibrating like the ABS had kicked in! Upon closer examination microcracks are emanating in a radial pattern from literally every single one of the holes. Previsously, using temperature sensitive paint I determined that all temperatures were within the acceptable range for the pads. It is just a function of the heat load and cycling that leads to the cracking. I am really disappointed. I had expected them to last at least a few years before requiring replacement. "

Also see this thread from the past-
https://www.northamericanmotoring.co...mp;topic=16883

 

Absolutely love the looks of the crossed drilled rotors. I have crossed drilled rotors in one of my cars for 10,000+ miles without any problem. As mentioned above, the crack is usually heat-induced. Since I use the car for street driving, cracking will not be an issue. :smile:

 

Thanks for the info everyone. I will look into it some more before switching them out. Where is a good place to check out the rotors for prices and all... Thanks again for the info. I love the drilled rotor look. I would love to switch it out, but I dont know if I can justify just putting them on for cosmetics... I think I need some performance explanation.... We'll see. If I do switch it out, I will post some photos. Thanks again everyone!

 

>>Thanks for the info everyone. I will look into it some more before switching them out. Where is a good place to check out the rotors for prices and all... Thanks again for the info. I love the drilled rotor look. I would love to switch it out, but I dont know if I can justify just putting them on for cosmetics... I think I need some performance explanation.... We'll see. If I do switch it out, I will post some photos. Thanks again everyone!

Cross drilled rotors are not for looks alone. They provide a bit of roughness for brake pads to adhere to and allow some heat and boundary gases to escape. These are the same benefits of slotted rotors but the slots don't make the rotor more prone to cracking. Appearance is subjective. Slotted rotors are more expensive. Dimpled rotors which are usually combined with slots works OK and are not prone to cracking. Powerslot rotors and others are treated with a cadmium finish that resists rust but with the heat of using them this finish may not last.

Sources of various rotors for MINIs-
http://helix13.com/html/products/brakes.htm
Slots in OEM rotor

http://www.webbmotorsports.com/suspension.php
PowerSlot Rotors


_________________
Aloha Hawaii

 

I have an '04 MCS with 21K on it.

I replaced the rotors with Brembo drilled and slotted (Brembo replacements drilled and slotted aftermarket) in the fronts and zimmermann drilled and slotted in the rears.

I got them on ebay for $200 shipped for all four....and put them on around 6K I think.

I rotated my tires today and noticed that the fronts were cracking near the holes, and almost all of them...However, I couldn't feel the cracks when I ran my fingernail over them...but I sure as heck could see 'em and it's bothering me now.

I don't track the car, I don't auto-x, though I will say I've had my fair share of 'spirited' motoring for sure.

I've got EBC GS pads all around as well and they make quite a bit of noise - much like a ringing of a bell and that is also quite annoying.

When I rotated my front left rotor by hand today, I noticed that at some point, it seems like the rotor was getting some kind of resistance and and other points, it rotated freely.

I'm thinking perhaps the rotor was not seated correctly...

I went and bought another set of the front rotors on ebay from the same guy a while back just so I had a spare set (I threw out my stock ones)....so maybe I'll just chuck the new rotors on there.

Any comments?

 

Do drilled or slotted rotors affect the amount of brake dust that accumulates on your wheels?

 

Not really.

The EBC GS pads reduced the brake dust significantly while providing better brake performance.

What more can you ask.....

 

I have 22,000 miles on my '03 MCS and am on my third set of rotors.

Sounds like your front Brembo drilled and slotted rotors met the same fate as my Zimmerman cross drilled rotors. Micro cracks on many of the holes- very very small but visible. It's all from heat building up- which happens more in the fronts than in the rears. So your rear rotors have no visible cracks? If no cracks then leave them.

You can replace the Brembos with the same drilled and slotted rotors but they will do about the same and crack in about the same time if you drive the same way.

I do some track, driving school, monthly autocross and street driving. My brakes get hot and I have gone through 4 sets of brake pads including being on my second set of track pads. I switched to Powerslot rotors with cryogenic treatment. The cryo treatment helps to make the rotor wear better and perform better. They are available at Tirerack.com (talk to alex) or webbmotorsports.com $124 fronts, $114 rears.

Left-untreated rotor after one track day
Right- cryo treated powerslot after three days on track

I don't think your rotor was incorrectly seated, I think it warped from the heat.

 

Thanks Minihune.

Well, during the initial install I know it was incorreclty seated as the rotor would not make it all the round when the guy tried to rotate it! Which is when I suggest perhaps he put in the lug nuts to hold the rotor in place and then attach the torx screw. I heard a little bit of grinding...and I do remember seeing a line going all the way around the surface of the rotor, almost as if a small rock had gotten stuck under the caliper. That line has since disappeared only to be replaced by the stress cracks. The rears have no wear at all.

Since I have the replacement rotors already, I guess I'll just swap em out.

Cracks look like my crude drawing attached, yeah?

 

From past experience.... drilled look great and are fine for street use but are prone to cracking with hard use.
Slotted are better but also do not seem to hold up as well as a good set of conventional rotors under hard use.
That being said, it all depends on materials, quality and machining process used for the rotors AND the choice of pads being used.

 

I'm not dumbing this down for you, just so anyone can understand.
A rotor is designed to heat up and the cool as quickly as possible, that's why the high end ones are ceramic (which by the way are the only ones to have cast-in holes, you'll NEVER find cast holes in a metal rotor). With this in mind, what you are looking for is a rotor with a good thermal mass (heavy...sorry), a good fin design: large, open, with lots of surface area. The best metal designs have a seperate hat section (the part that attaches to the hub) so that the rotor can expand more radially, and avoid coning during frequent stops. Paints and coatings on the plates (braking surfaces) are useless (except for corrosion resistance during initial storage), and wear right off. The most important feature of a rotor is its ability to hold and dissipate heat to the air, without transferring it to the other components. A very open wheel design helps too.

 

Thanks for the helpful info. Sorry to bring up an old thread again, but I'm thinking about getting a BBK for my MINI.

I'm just missing the cash and my MINI would be awesome!!!

 

I recommend Brembo drilled rotors, ferodo DS2500 brake pads and Motul RBF600.

This in my opinion, is just as good as it gets,
for better you will have to get a Brembo Big Brake Kit.

 

OR......
Brembo Sport Slotted rotors (see above about cracked drilled rotors),
Turner Motorsport caliper bushings, stainless steel brake hoses,ATE Super Blue brake fluid, and EBC Green Stuff pads.
This, in MY opinion is as good as it gets, for better you will have to get a StopTech Big Brake Kit.

Jim

 

Mine are RacingBrake, haven't checked them for cracks yet...

 

You probably won't get cracking and crazing if you just street the car.But if you do aggressive DEs or racing your fronts will start looking real scary. Every track car I've seen with drilled rotors have been real scary looking

 

I had two different sets of DBA slotted and cross drilled rotors. They held up ok for street use but surface cracks developed after track days. The company said that as long as the cracks did not extend from one hole to the other there was no saftey issue. I have sence then converted to slotted only .

Randy
M7 Tuning