Crossed drilled/slotted rotors.

What real advantages or disatvantage to having crossed drilled rotors, on a daily driven car. Is it better to go slotted, versus drilled, or what about a combo to both? Do they withstand warping longer? I know they are meant to keep the rotors cooler, but what if you dont upgrade to a larger rotor, but keep the OEM size?

A brake converts kinetic energy into heat energy. So, a slotted/drilled brake more easily converts kinetics to heat because more surface area is exposed. Think about air-cooled engines that have all the fins on them, slotted/drilled rotors are similar.

Originally posted by kbslacker
What real advantages or disatvantage to having crossed drilled rotors, on a daily driven car.

None I can think of... They do look cool though :)

Originally posted by kbslacker
Is it better to go slotted, versus drilled[/B]

Yeah, that's what I'd do...

Now I shut up and wait for smarter guys to reply...

Cross-drilled or slotted rotors do not fade as easily, stop quicker, and last longer than conventional rotors. As far as which is better, I think they're about even.

I think enginerd said it all. But I would like to add that certain cars have no need for these. Unless your car needs some real stopping power then I would say they are a waste of money. I have vented rotors on my LeBaron and it stops just fine. I have no need for cross drilled or slotted rotors.

Well, when it came time to replace my rotors. I opted to spend an extra $10 per rotor and get Brembo cross drilled/slotted rotors. I really wasnt looking to stop faster, or some crap like that. I think they look nice peeking through your rims. :) But on another forum we are having a nice little debate. Some people say they are just shit, and not worth it. I was looking for more info on them. Thanks so far. :)

I have cross drilled rotors on my VR4s and I can tell the difference.

as its my understanding, and physics background, the slots and holes are to help cool the brakes a lot faster. Cooler brakes stop better, and yeah, there is more surface area, to COOL with, but not to STOP with, cause the brae pads arent even touching those parts.

Originally posted by Steel
as its my understanding, and physics background, the slots and holes are to help cool the brakes a lot faster. Cooler brakes stop better, and yeah, there is more surface area, to COOL with, but not to STOP with, cause the brae pads arent even touching those parts.

That is true! and it's why slotted are more preferable, IMO...

Slotted and cross drilled are both techniques to help get brake gas vented. This helps keep the rotor cool and helps to reduce fade. The do overall have more braking power.
Those are the advantages, disadvantages contrary to popular believe the do not last longer! and they also shorten brake pad life. Unless you you are using them with a baer calipers and something like hawk brake pads you really won't gain much from them. Also unless you are driving a heavily modded car used ofr drag or SCAA the ar e a waste of money, u'd be better served buying just plain bigger rotors

It's up to you KB . . . but along the lines of some of the earlier replies, they both have advantages over stock or just oversized rotors.

The slotted/drilled rotors are advantageous because the holes, and slots provide ventilation for the rotors. This prevents your brakes from getting very hot which is not desirable. Somebody mentioned that you will be able to convert energy to heat quicker with slotted/drilled rotors . . . I don't know what that's all about.

You don't want your brakes getting hot . . .

When your brakes are very hot you will not be able to stop as well as you should be able to . . . a problem known as "brake fade"

GTSTANG mentioned that unless your involved in some form of racing these rotors won't be much help to you, and for the most part that is correct, but again . . . the choice is yours.

This is true because the only time that your brakes should bet hot enough that you need to consider alternatives to stock rotors is if you are CONSISTENTLY braking heavily . . . like during racing, when you can see the glowing brake rotors.

While a lot of us like to drive hard on the streets, you should not be able to get your brakes hot enough to have a significant braking problem.

If you pay enough attention to your brakes and the overall "feel" of them, you should be able to notice the difference when you change your rotors.

Cross-drilled is a better idea for street applications than slotted, but I can't remember why.

Originally posted by i_rebel
Cross-drilled is a better idea for street applications than slotted, but I can't remember why.

In all honesty, it really doesn't matter one way or another. Pad material and normal working heat range are the two most important things, besides that if you really want to get into increased braking performance you should consider building brake cooling ducts into the system. You can make plain, slotted, cross-drilled or cross-drilled & slotted rotors work perfectly in virtually any application. You can go to the track and see this for yourself, or just look at some of the best braking performance cars from the factory. What sort of rotor treatment has been done is really more for looks and personal preference than anything else.

Originally posted by texan


In all honesty, it really doesn't matter one way or another. Pad material and normal working heat range are the two most important things, besides that if you really want to get into increased braking performance you should consider building brake cooling ducts into the system. You can make plain, slotted, cross-drilled or cross-drilled & slotted rotors work perfectly in virtually any application. You can go to the track and see this for yourself, or just look at some of the best braking performance cars from the factory. What sort of rotor treatment has been done is really more for looks and personal preference than anything else.

- Well ain't that some schitt!? I did a whole shitload of research before changing my rotors to cross-drilled about two years ago, and thought that I found some pretty reputable sources for the wisdom that I now sling about like so much filth . . .

- You mean to say that they offer no improvement over the performance of a stock rotor of the same size? I find it hard to believe, but I digress . . .

- Thanks for the insight Texan!

Originally posted by i_rebel


- Well ain't that some schitt!? I did a whole shitload of research before changing my rotors to cross-drilled about two years ago, and thought that I found some pretty reputable sources for the wisdom that I now sling about like so much filth . . .

- You mean to say that they offer no improvement over the performance of a stock rotor of the same size? I find it hard to believe, but I digress . . .

- Thanks for the insight Texan!


If they are the same size as stock, i dont think you will get any benefit. If anything, you will lose braking performance because of the smaller amount of surface area. The main reason I switched to cross drilled/slotted, was to help prevent my rotors from warping, plus they look good sitting underneath the rims. So far, so good. :) I know there are other ways to prevent warping, but for a extra $10, why not get a better quality rotor.

ok...
here's the rundown.
the slots/holes DO keep the rotor cooler...
however, they are designed to flow the built up gas (from the friction of the pad and rotor) away from the braking area....
what that means is that as your brakes heat up from repeated usage, the amount of waste gas b/n the rotor and pad causes "brake fade" as it takes longer for the pad to come in full contact with the rotor.
so, if you have the slots/holes, it allows the gas to escape from under the pad, so there is no brake fade.

i drive my car hard every day, and for the driving i do, even with a set of rotors that are the same size as stock, i do notice alot more consistency in the braking.
the rotors may not change your braking performance (distance, etc) but they will help you be more consistent in your distances...

like if you did 5 60-0 runs with holes, you would notice a fairly consistent distance, whereas with the non drilled, you will notice that the distance becomes longer.
so the first stop may be equal b/n the two, but the last ones wont be...

so...
main reason is consistency

ideally stepping up to a bigger rotor w/more swept area and holes/slots will cut down the distance AND be consistent...