drilled rotors not recommended for track use?

[ECLIPSE95]

I was looking at some brake rotors and I saw some brembo rotors that are just cross drilled(not slotted), but they have a note saying: not recommended for track use? why is that? does that mean the brake rotors are weaker under stress? and if thats true then why are the big brake kits slotted and cross drilled??

 

[the_mork]

Use the search button this has been covered a few times.

Yes, in certain situations the rotors will be weakened enough that under extreme duty they can crack. This is not common and would almost certainly not happen during normal driving. It really isn't likely to happen on a good rotor with a good pattern.

 

[ECLIPSE95]

I've searched, its probably the way im searching so I just asked. Thanks for the info.

 

[kahl23]

Drilling takes away a lot of material from the rotor and causes it to heat up faster, causing stress fractures, which causes this.

Slotted rotors give you the same result as cross drilling but retain more material on the rotor, doing both is the worst, as you are removing the most material from the rotors. Look at what real race cars run, its almost always slotted rotors. However, Porsche loves to use drilled rotors, maybe they just assume that their customer base can afford regular replacements.

Some more good reading here.

why are the big brake kits slotted and cross drilled??

Looks, plain and simple, the more things it has done to it the more people think it's worth.

Mork, read my first link, it's an eye opener.

 

[ECLIPSE95]

That helps me even more. Thanks. I'm probably just going to stick to the typical blank rotors it seems like for my DD.

EDIT: just read that link. Scary stuff. Good thing I asked before purchase.

 

[the_mork]

Mork, read my first link, it's an eye opener.

I had not read that particular thread but it is similar to other information that I have seen. IMO the danger involved has a lot to do with how hard your push the rotors and what condition they are in to start with.

I personally wouldn't recommend them, I run slotted rotors on my car but I also wouldn't race to the nearest shop and replace some drilled rotors if I bought a car that had them on already. Most drivers on the street (and mild courses) wont put their rotors through enough stress to cause danger.

It really is a matter of experience and opinion. If you've experienced one failure you'll never ride in a car that has them again but there are a number of knowing people who think they are fine for daily driving.