OriginalSterm

I may be getting rather close to changing brake rotors. For now, I'm going to stay with the stock setup, but I have a question about which rotors I should fork over money on. It's primarily a street car, but will see several DE's and AutoX's next year. What does everyone recommend?

OriginalSterm

Got some people voting, but no reasons why. I need to weigh my options.

Jaak Lepson

Cross-Drilled fill up with road crap which causes damage to pads & rotors. Our brakes are good as is ... maybe upgrade the pads, fluid and make sure the cooling ducts are in place.

Jaak Lepson

Jon Moeller

Everything that I've read (from knowledgeable people) says that cross-drilled is purely cosmetic, and that unless the rotor is cast with the holes in place (making it not a true "cross-drilled" disc), it will crack far in advance of the solid factory rotor. Gas slotting is said to be of some value, as it does help clean the face of the pads, and does not compromise the structural integrity of the rotor.

On my track/street car, I will run either solid or gas-slotted rotors.
-J

tifosiman

I have slotted rotors combined with my S4 calipers and I am pleased, no signs of cracking, and have never had brake fade.

I have seen two sets of aftermarket "drilled" rotors crack, I'd shy away unless the holes are cast.

Tifo

ninefiveone

Cast or not, cross drilled rotors crack under heavy track use. We're not talking about within a day or even within a year but they will crack before the actual life of the rotor expires.

I haven't seen a reason to go with anything but a plain faced rotor. I've never needed a slot to "clean" the face of the brake pads although I can see slotted rotors helping to bed pads in faster.

Ahmet

I would go for regular rotors as well. If slotted weren't so much more expensive, that would be a descent choice. If increased braking power is what you're after, pads and fluid will help. If you're on the street, tires is what determines the limit anyway. If doing track events, make sure the ducting is all there also.
Ahmet

Sam Lin

For any track use, stock, they'll last the longest AND be the cheapest by far. Now for the street, cross-drilled look best, and cost the most. If you don't want to swap between street/track rotors, then go with plain stock rotors.

Sam

Waterguy

You can get special hubcaps that make it look like you have cross-drilled rotors. Phat!

Ahmet

From my experience slotted cost the most, followed by true cast "holed", then quality stock replacement, and finally a cheaper stock replacement.
Ahmet

M758

Funny..
I have run zimmerman cross-drilled rotors on my 944-spec car for some like 2.5 years now. I figure 50 track days with 20-30 races. I have gone through the following pads on these rotors

1.5 sets metal masters
2 sets KFP Magnum Golds
1 set Hawk Blues.

Rotors look nice with plenty of thickness and NO CRACKS!

I am trully surprised they have not cracked yet. I also have 3" brake cooling ducts installed and the car is 2450lbs.

I can't say they are really better then stock, but I feel I have gotten my money's worth from them. I figure I can go through another set of pads before I need to change the rotors.

sybelix

yup, definitely stock; drilled won't last,
there are problems with drilled rotors even with couple years old 996 GT3.
I think in our cars they are purely for the looks.
Stay stock !

DAR951

As everyone else says, skip the cross drilling... But do consider having whatever you settle on cryo'd/frozen. Not that expensive and add's considerable life. Take a look at the "Frozen Rotor" web site (www.frozenrotors.com) for more comprehensive info...

mochman

Cast cross drilled rotors are fine zimmerman makes them and is an OE supplier for porsche. About the only difference I'm aware of between "factory mo30 rotor and the zimmerman is the oe comes with the hat painted black. New 996 rorors crack all the time the small cracks don't worry about, worry when it starts to crack around the circumference. I've yet to have a cross drilled fill up with road debris. They also brake a lot better in the wet, trust me I've seen test results to prove it.

Laust Pedersen

My vote is for slotted rotors, which in addition to blowing the dust away also provides a whiff of fresh air to the pad-rotor interface (the hottest area). I still use standard rotors though with OG Racing brake coolers found here: http://www.ogracing.com/eshop/itemde...13&showbrake=1
but my rims (Design-90) still get quite hot (maybe 50C) after a few laps on Willow Springs.

At the risk of being controversial, the cryogenic treatment is against what I have learned in metallurgy, namely that nothing happens to the polycrystalline structure (in steel) below a certain temperature (maybe 300 - 400C) and therefore not to the macroscopic properties either.

Laust