Which is better?
The cross-drilled rotors, slotted or the combo that's both crossed-drilled and slotted?

 

Slotted!
Cross drilled just causes them to crack. And the only way it helps is by reducing weight.

 

i got both. I'm very happy. They run much cooler than regular rotors as tested by my bare hand (dont ask)

 

so .. you touched the stock ones bare hand, then did it to the new ones.... how hot was it... lol

 

Hey he said not to ask!

 

so, i had to...

 

I talked to a guy at SPORTBRAKES and he said that the combo rotors are what he sales most of. Combo being drilling and slotted. Maybe those are the best to go with. Also heard from a couple of others that slotted rotors where like cheese graters on your pads. Anybody know from experience?

 

the edges are rounded on the ones I sold (from sportbrakes) so it didn't cut into the pads nor dust badly. It still helped with pad seating and the drills keep it nice and cool. I don't do any heavy braking or auto-x on these brakes but for street rotors they are perfect.....they even have a cool sound when you roll to a stop with the window down.

 

question:.. aren't you loosing surface area when you go with drilled rotors. effectively reducing braking performance?

 

the very minimal amount of surface you lose is nothing when you think of the cooling advantages of the drills and the fact that the slots help vent off the air that is trapped between the pad and rotor. This gives (supposedly) better pedal feel.

i know my p5 has worn these "combo" rotors for almost 15K miles with no problems and my pads still look brand new. I'm pleased.

 

if you don't do any hard driving, crossed drilled and slotted rotors will be fine. in fact, stock rotors will be fine for that application. however, for track conditions, slotted is the only way to go. you lose minimal surface area and still have an effective means of letting brake gas escape. under harsh conditions, drilled holes not casted from when the rotor was made will crack.

powerslot just released their cryogen'd slotted rotors. they're a bit pricey, but their performance factor is high.

 

Yah....it's like a :
"whirrrrrrrrrrrrrrr"
It sounds great...lol!

 

They crack because some companies (I won't mention which ones) take a set of rotors and just drill holes in them. And they drill too many which weakens them.

I have cross-drilled Brembo rotors and they are awesome!

 

So, if you won't mention the companies, then someone might buy them and suffer the indignity/problem of cracking. Come on dude, help us out!

 

I've heard it was companies like KVR which use Brembo rotors and drill holes into them. As well some people have mentioned that the e-Bay ones may be like that too.