Slotted and cross drilled rotors for street: opinions

[Right_LiRrr]

Correct me if I'm wrong, from a technical point of view, my undserstanding is that slotted and cross drilled rotors actually cause less braking power, all else being equal. This is because they reduce surface area contact between the disc and the pads. However, because they offer much better cooling and hence reducing brake fade, the pluses totally outweigh the minuses once you do some serious braking.

So for street use, I know with slotted, it should give better overall braking because of the better cooling versus the minimal surface area loss. But is cross-drilling on top of that necessary?

Other than looking cool, I would think 90% of the time on the street, you braking load is not heavy enough to have the extra cooling effects of cross drilling outweigh the loss of surface contact.

Price is not a factor here because I already got the cross-drilled ones anyway . The slotted for the rear were out of stock and I didn't wannt wait another 8hrs for service...long story.

[TheStang00]

i was under the inpression that slots or vents improved braking because the pad would catch the edge of the slot when it when by thus causing more friction but wearing the pad out a little faster. but idk. atleast you know with all that cooling that your rotors wont warp. some cars probably should have drilled/vented rotors. the stock brakes on our malibu are terrible, they warp within a month of being put on every time. and after searching online it appears to be a common thing.




damnit! cant sleep

[Right_LiRrr]

Originally Posted by TheStang00

i was under the inpression that slots or vents improved braking because the pad would catch the edge of the slot when it when by thus causing more friction but wearing the pad out a little faster. but idk. atleast you know with all that cooling that your rotors wont warp. some cars probably should have drilled/vented rotors. the stock brakes on our malibu are terrible, they warp within a month of being put on every time. and after searching online it appears to be a common thing.

Yes, sorry I missed that, I heard the slots cause the initial braking to bite quicker...but overall I think they would still provide less braking power?


Oh and it's 7pm here...sucks to be you :-P

[turtlecrxsi]

I had cross-drilled Power Slot rotors on my car and they lasted 2 years. I really abused them. I think I even changed the pads without turning them too and they squeaked for a day but still were in good shape. They eventually warped when those pads wore out... more abuse. So I replaced them with Brembo Blanks and new pads which are fine since I minimized the abuse of my car. But, honestly IMO, the cross-drilled discs seemed to have better performance. I'd say they're worth the extra $

EDIT: Apparently, I don't know what I'm talking about. If regular brakes are fine, then I'll be damned if I spend 90 bucks for Brembo blanks when I can get OE replacements for much cheaper... sheesh.

[Polygon]

Here is the truth. While slotting actually improves initial bite, cross-drilling is just a marketing ploy. You will not find cross-drilled rotors on ANY race car.

The fact of the matter is that if you really want to have the look of cross-drilled rotors you had better get bigger rotors because when you cross-drill you're removing material from the rotor. This reduces the surface contact between the pad and the rotor and it lessens the rotors ability to dissipate heat. Some might tell you that it prevents outgassing but that is a myth. Outgassing was a problem with older brake pads. Any new brake pad is chamfered and has a slot in the middle to prevent outgassing.

So, unless you increase your rotor size you will decrease your braking performance by using cross-drilled rotors. They are worthless. However, slotting is useful but you will go through brake pads very fast.

[Jet-Lee]

Not all current brake pads have the slot in the middle.

I've had 3 different pads on my my car, and all faded horribly when under hard braking. I'll be getting slotted rotors next time around.

It's not the slots on the rotor that cause more pad wear, it's the more abuse put on the pads because they're not fading anymore. If you notice, the slots run in an arc. If they were perpendicular to the tangent of the hub, then yes, because it would be like a potato-peeler shaving a layer off. It's like rolling a big cylinder over a line in the sidewalk. If you go head-on, you get a nice dip and bump. Go at an angle, and you don't even know it's there and it has no effect whatsoever. Make sense?

EDIT-Organic pads, some of the cheapest brands, still do out-gas. That's the reason for the slots in the middle of the pad. If they didn't out-gas, why are there slots in the middle?

[corning_d3]

I too think drilled rotors are a gimmick. I've never seen a race car with them, but I've seen a lot of slotted ones. I'll be getting some slotted rotors for my Monte soon, since there isn't a pad for my car with a slot in it. The edge is chamfered on the slot, so it doesn't cut the pad, but I do imagine it cause more wear than standard rotors.

[Polygon]

Originally Posted by Jet-Lee

Not all current brake pads have the slot in the middle.

I've had 3 different pads on my my car, and all faded horribly when under hard braking. I'll be getting slotted rotors next time around.

It's not the slots on the rotor that cause more pad wear, it's the more abuse put on the pads because they're not fading anymore. If you notice, the slots run in an arc. If they were perpendicular to the tangent of the hub, then yes, because it would be like a potato-peeler shaving a layer off. It's like rolling a big cylinder over a line in the sidewalk. If you go head-on, you get a nice dip and bump. Go at an angle, and you don't even know it's there and it has no effect whatsoever. Make sense?

EDIT-Organic pads, some of the cheapest brands, still do out-gas. That's the reason for the slots in the middle of the pad. If they didn't out-gas, why are there slots in the middle?

1. Show me a set that does not have the slot in the middle. If they exist then they must be some of the cheapest pads out there.

2. The slots are what chew up the pad, plain and simple. Run your hand across a blank rotor and run your hand across a slotted rotor. The slotted one is more abrasive.

3. Brake fade is caused by boiling brake fluid, inadequate pads, and rotors that are too small for the weight of the car. Cross-drilled rotors will increase the chances of brake fade, not reduce them since you are reducing the rotors capability to dissipate heat.

4. Duh, that is what I said. I said outgassing isn't a problem anymore because of the slot in the middle.

[TheStang00]

these have no slot. for the search i typed discount brake pads... so they are probably cheap.

[CassiesMan]

For street applications, your normal brakes are fine. You don't need big brakes, cross drilled or slotted or any of that stuff on a street application. Hell, you don't need them for 1/4 mile track applications either.

[2.2 Straight six]

race cars don't have drilled disks/rotors. they sometimes have "dimples" in the disks, but that's usually only endurance racers, and they're used to monitor brake wear, the deeper the dimple, the more disk life is left. they usually have a two pairs of these dimples, opposite each other one dimple bigger and deeper than the other.

[Jet-Lee]

Originally Posted by Polygon

1. Show me a set that does not have the slot in the middle. If they exist then they must be some of the cheapest pads out there.

2. The slots are what chew up the pad, plain and simple. Run your hand across a blank rotor and run your hand across a slotted rotor. The slotted one is more abrasive.

3. Brake fade is caused by boiling brake fluid, inadequate pads, and rotors that are too small for the weight of the car. Cross-drilled rotors will increase the chances of brake fade, not reduce them since you are reducing the rotors capability to dissipate heat.

4. Duh, that is what I said. I said outgassing isn't a problem anymore because of the slot in the middle.

1. Review the post below yours. I don't know where they were bought or for what price, but I've installed at least 3 sets of pads that didn't have a slot. Sure, I thought it was weird, but it wasn't my vehicle and they bought them some warranty, whatever.

2. Not plain and simple. Did you even read my example?

3. I didn't say shit about cross-drilled rotors, did I?

4. Outgassing is an action. Regardless of whether or not there is a slot, outgassing still takes place and still has an effect on the braking capabilities. The slot just helps reduce the effects.

[Underground_Killah]

i dunno, i notice my breaking from faster times is much more accurate and faster, and it's been safer for me since i've put mine on. i suggest them

[Jet-Lee]

Slotted, cross-drilled, or both?

[-Jayson-]

ive also heard that drilled rotors cause uneven wear on the pads, because with the slotted, it scrapes the whole pad, but with drilled, its just where the hole is. So over time you can carve a groove in the pad where the dot is.