manalex

Crack was all the way through. I'll never use drilled rotors again, at least not up front. First sign of any issue was turn 10A at RATL.

CWhaley

That does not look like an OEM rotor... Was It?

Also, the crack is not (in my opinion) directly related to the crossed drilled hole

manalex

This happened last year. I'm not sure if it was OEM as it was already on the car when I purchases it. I don't think there's an OEM cross drilled AND slotted rotor, but I could be wrong.

The crack propagates from one of the holes to the outer edge. This is why I attribute the failure to the cross drilling. I may be wrong but cracks eminating from these holes is very common-at least in my limited experience.

todera

That is what I thought, thanks.

CWhaley

The slot is why I made the not OEM observation.

It appear the primary crack started mid way between the edge and hole (circled in red) from Heat saturation. Again, just my opinion.

mglobe

No way that's an OEM rotor.

manalex

Not sure you can make that kind of analysis from an iPhone pic. And believe me the picture did not capture the amount of deformation-it's more than just a simple crack.

I use to track a 996TT, much faster and MUCH heavier. Had to replace front rotors often due to cracking. Eventually upgraded the brakes to 6 piston and 2 pc floating. Most of the cracks, by far, started at the drilled holes and propagated outward. Most people advised that the rotors needed to be replaced whenever a crack from on hole met another or the edge of the disc. Never had a failure like this on the turbo (thank God), but I feel the causes in both cases are attributable to the holes, at least in part. The failure pictured just confirmed my sentiment that crossed-drilled rotors suck for tracking. Again just my opinion.

CWhaley

I could see in the photo that the area I indicated was deformed. so after years of analyzing failures from worse imagery... I can say that it really was not the holes fault.

TRT41

^^^^^^

Classic

manalex

The edge of the crack is at the hole-this is undeniable. Whether it started there or not is irrelevant to me, it's involved in the failure (my opinion). Based on your pictorial analysis can you honestly say that the crack would have been as large, or as severe, without the hole there? I think not, again my opinion.

Look, I don't want or need to get into a pissing match about this rotor/crack. We all have our preferences based on our experiences. Good luck to you with your's and I wish you the best. Based on my experiences I don't see any disadvantage to avoiding crossed drilled rotors for track use when possible.

jrgordonsenior

Since I built my 996 in July 09', I've probably put in excess of 70 hours on it running both POC and NASA's full schedule of 17-18 races each per year. To date I've replaced one, that's correct, 1 front cross drilled OEM rotor. I run Pagid RS29's up front, RS 14's rear. Yea I've got some cracks between the holes, but none to the outside edge. You guys need to quit braking so much .....

garrett376

It's nice to be light, with lots of rubber!

manalex

I've come to this same conclusion. There is a proper technique to braking, one day I'll figure it out.

coinboy

Just signed up for the Sebring Club Race as the first ever "SP996" !
Can't wait, who is with me???!!!!

CWhaley

give'em hell!