BradB

So do you think I can get a couple more track days at NCM out of these rotors?

Dewinator

Wow those are really cracked. I just changed out my rotors this weekend because they had gotten pretty good ruts worn in them after 64k miles and they had zero cracks.

Spyerx

I'd replace them or have a set of spares on hand. Go with slotted.

BradB

My car has 11k miles on it at this is the fourth set of rotors. That's what track days will do to you.

LexVan

Brad, when I do Tech Inspection for PCA events (DE and Club Racing) we inspect the rotors and pads, and a bunch of other stuff. On rotors, we are looking for these check/crack marks at the outer most edge. That would be bad. Yours look pretty normal with a tracked car. You do not have any cracks at the outer edges. I like Spyerx's answer, have a set of spares ready to swap out in the paddock.

BradB

I have another set of OEM standing by, but was hoping to get another track event with these. That said, I'm asking because I'm not sure if these are completely toasted or OK for another run. I honestly don't know how far they can go.

Any suggestions on a brand of slotted that isn't super expensive?

Dewinator

Wow. I'm doing a track day this weekend uhoh. At least I know how to do it now, the first rotor took me like 6 hours and I was down to under 30 mins by the 4th.

BradB

Thanks! That's helpful. I'll give them another shot. It's not hard to swap if I need to. Packing will be tricky, though. I hope my wife can hold them on her lap!

Spyerx

LexVan had the more complete answer.

Drilled rotors are toast when the cracks reach and edge (you need to look front and rear) or the crack touch hole to hole. Or they reach thickness limit. Porsche spec is less, like 5mm long cracks or something.

You'd probably be wise to invest in slotted rotors. They last a lot longer for track use.

BradB

Yes. I'll start looking into them. Any experience with brands other than Girodisc and similar $$$ ones? Those are nice but beyond my budget.

LexVan

Does cryogenic rotor treatment help extend lifespan?

Spyerx

My experience is the better rotors last longer. I use Brembo on 2 of my 3 911. So costs can equalize. Plus you don't lose a track day if your rotor cracks to the edge from a hole.

Cryo? Who knows maybe.

BradB

Well, I kept my replacement OEM's in the fridge and it didn't make a difference.

KA MOTORSPORT

- The discs themselves look pretty worn (5-6 mm of radial crack from the drill holes according to Brembo Racing and also a visually noticeable lip on the discs).
- If you have a 991"S" model, Brembo upgraded discs (350 x 34 - Front, 350 x 28 - Rear Type 3) and RT RE10 endurance pads. Nothing available for non-S models from Brembo (the only brand we choose to sell). PM us for more details or RL pricing.
- Cryo must not help, Brembo or AP (the two leading brake suppliers) don't really offer / do that for their racing discs.

Jerrygreene

my .02 Drilled rotors on track will not last any where near slotted rotors....