DDP

Do you really think that the rotor bends? Well, in my mind, that makes sense. I can't remember where I read that, I wish I could find the article. I'll look for it.

Manning

Carroll Smith wrote an article about it and from my experience I tend to agree with what he had to say. IIRC the premise is that most people think of 'warping' as the rotor looking like a potato chip when it happens, but what actually happens is that the side to side runout of the centerline of the rotor does not change, but rotor thickness does. This can happen by pad transfer to the rotor surface, which I have seen a number of times and is quite visibly obvious at times, or the rotor surface can collapse in between the vains. Also the rotor hat can become deformed and cause side to side oscillation, but the rotor itself is still relatively true.

Manning

Also, I have run ATE slotted rotors on the 924S and my old Scirocco and have not noticed appreciably increased pad wear.

RedlineMan

Hey;

I only read the first question. I don't need to read two pages of this and that. I will give you the straight scoop on drilled -vs- slotted from someone who lives in the world where they were both designed to be used.

Drilled and slotted rotors were designed for HARD TRACK USE. They both accomplish the same things.

1) The added friction of pad hitting edges puts heat in the pads/rotors FAST. This makes them grip harder earlier and reduces stopping distances.
2) They allow an escape route for anything that might come between the rotor and the pad surface, which might decrease braking efficiency. These include water, off-gasing of hot pads, etc.
3) The drilled variety will cool better and weigh less, to a very moderate - if even negligible degree.
4) Rotors cast with holes will hold up far better than drilled. Who and how they are drilled also has a big effect, if only drilled are available.
5) Either variety of "holey rotors" will last "forever" on a street car because you will never get them hot enough to cause them to fail.

If you need these rotors for track use, I suggest slotted. If they are done properly, they will not crack. Drilled/cast hole rotors WILL crack guaranteed if used hard. They are intended for RACE cars where rotors are replaced as consumables like brake pads and tires.

These types of rotors have only ONE purpose on a car that is not driven on the track, and HARD at that - that purpose would be BLING. They are utterly pointless on a street car, except for looks. If making your car "look cool" is what you want, I guess this in one thing you can do.

Personally, I think a car looks much cooler with rubber marks and stone chips all over the front end, and numbers pasted on the doors. REAL track markers.

Serge944

So this front end looks good to you?

eman930

Im running slotted rotors that are cryo treated with some hawk HPS compound pads, I havent had a problem and my pad like is awsome longer then OEM. Love my setup

Eyal 951

Nah, thats not track like... thats just beaten up... How was I less coherent?
~Eyal

Serge944

Re-read what you wrote out loud. You'll see what I mean. The SpellCheck button is also a quick way to catch errors, if you care.

Btw, it's not beaten up: it's used. Functionality is most important to me anyways.

Bri Bro

When I ran the long tracks, the same advice was stated over and over again. Don't use your brakes for any period of time after coming off of the track or you will warp your rotors. I never heard you will melt your brake pads on to the rotors. As for my choice, it is solid rotors. They are heat sinks after all. Surface area matters for effect heat transfer.

GlenL

What we got here is classic "Internet Information:" lots of opinion about facts with frequent contradiction between them. I'm thinking to start a blog...

Let me try to sort this out:

Warping: Once the pedal pulsates and the steering wheel twitches, you're screwed. This can be pad deposits, differing wear depth or actual warping. The cause only matters if the rotors are solid as only those can be turned.

Holes: Get cast, not drilled. If used hard they'll crack. Might crack if not. Not a performance upgrade for the street but a cosmetic upgrade. Will help cooling and pad out-gassing for the track.

Slotted: Not a performance upgrade for the street and not that cool to look at. A good choice for the track as they crack less and cost less than holed rotors but help the out-gassing.

Solid: The least expensive. No attitude shown. (paint the calipers) Can possibly be turned when worn. A less good choice for the track (See above).

Some bad info in the thread: "rotors don't warp," "rotors don't crack" and "Edges help stopping." "Yes they do," "yes they do" and "Holes are bevelled and pads are really flat" respectively.

flamingeye

link

Manning

Yeah, that article. Thanks.

Eyal 951

last time I checked, the spell check doesn't work. Maybe its on my end. There really weren't that many errors... just signs of someone typing fast. That front end is not "functionality" people here with double your miles still don't have front ends like that. A bra is functional too... only a hundred bucks, and then you wouldn't have to brag about how awful your front end looks.
~Eyal

Manning

Firefox maybe? Or do you have popups blocked?

Serge944

A bra like this one? By the way, it's not very "functional" as it increases ambient temperature in the engine bay.

Double my miles? Show me someone with 510k miles.

I wasn't attacking you initially, but you just don't stop. Why don't you have another party so someone can fix your car for you? It's been on jackstands the majority of your ownership...

What a joke.