hanseng1

Question regarding rotors and longevity.


Relatively new to track days. Running an 02 C5Z, effectively stock, with Carbotech XP10s up front, XP8 in rear, on Nitto NT-05s.


Road Atlanta is my home track. As I gradually improve in times, I'm noticing I'm getting "enhanced" heat checking on the rotors (see below). The pictures are from approximately 3 hours of track time. The cracks don't go through the rotor, or from hat to edge, but are deep enough to be easily felt when running a finger over them. Are these safe to run?


I'm moving to DBAs from KNS in the future, but wondering where a rotor is considered unusable. What causes this excessive wear? Something that is cured with ducting, or am I basically screwed if on stock rotors?


Thanks in advance for the help.

wtb-z

I don't change rotors until they are actually split open. This means carrying lots of spares.

As you pick up speed stock rotors will probably look like that after a session or two.

danh52

I'm interested in hearing what the experienced have to say on this subject.

I haven't tracked my C5 yet but on other cars I've tracked I have never had a crack that big. I've replaced the rotors when they are still only showing the smaller checking. I think I would replace them but I might just be more conservative.

danh52

Good to know. My MINI Cooper with Wilwood BBK hardly ever even got the micro cracks and my Camaro with the ZL1 Brembo's didn't check at all. I like to brake late and hard so I might be looking at an upgrade to the C5 front's. We'll see this summer.

CHJ In Virginia

That rotor probably has several sessions left in it. Inspect carefully after a good cool down lap. If the crack extends to the edge it is time to trash it. If your fingernail catches in the crack you are getting close. The major thing you need to do is get some cooling air to the rotor. Search the forum for the DRM ducts and use in conjunction with the LG spindle ducts. They are not too hard to install and will greatly enhance rotor life. The next decision you have to make is rotor type. Either stay with cheap NAPA stockers and replace them often or spend the bux on a top quality set of DBA 5000 two piece rotors. I tried various brands, cryo treated, and none provided any benefit over stock cheapos. Forget the drilled / slotted crap that is out there - total waste of money for track use. THE DBA have a noticeably thicker friction surface than stock and will last 5X longer, especially WITH COOLING DUCTS. IMHO Bottom line do the ducts and DBA rotors.

hanseng1

Thanks all for the replies.


I have DRM ducts in the mail, which will go on before the next event. Just installed KNS's DBA rotors (the one piece, 4k).


When I got into this a year ago, I didn't anticipate becoming obsessed. Now, I'm re-evaluating some of my decisions with the car. Mostly concerned at this point with operating cost over time rather than the upfront sticker price. XP10s are lasting six hours, and the "enhanced heat checking" noted above is after three (half of that in traffic so reduced braking effort). Does moving to a good two-piece materially reduce operating costs, or do I have to move to a BBK to see improved durability?

Last C5

Yes, going to a good two piece rotor does reduce operating costs.

harrydirty

I just replaced my DBA 4000 T3 rotors to a new set......the previous set lasted 30 track days, which is amazing value. One rotor had a crack to the outer edge, the other rotor was fine with heat checks. I changed both just to be consistent.

I drive a 2007 Z06, stock calipers, Raybestos ST43 padlets, Quantum Motorsports brake duct kit.

spearfish25

I'm impressed with the Raybestos ST43s. Rotors seem to be wearing much better than they did with Hawk DTC-70s.

hanseng1

Thanks all for the feedback.


Sounds like I need to go ahead and go two-piece after these new rotors go.


I've pretty much stuck with Carbotechs thus far (aside from a brief experience with Hawks) because I've heard they're very rotor-friendly. Perhaps I should give the Raybestos a shot as well.


Back at RA on the 10th. Hopefully, with the DBAs and new ducts, I'll fare better in the wear department.

blkbrd69

When does a "heat check" turn into a "crack"?

While you are walking to lunch. Normally noticed 30 min before your next group session on track.

harrydirty

Going two-piece is a good choice.......please keep in mind that the DBA 4000 T3 rotors that lasted me a while are one-piece, so that may give you more options cost-wise. Either way, it will be a great upgrade.

Adam@Amp'dAutosport.com

We're these rotors used with hawk and Carbotech pads?

Soloontario

The problem with cracking is that it may not become evident until the rotor has cooled so it is really worth taking a look before you go out for the next session. I have sat in the paddock and heard the dreaded loud "ping" which can sometimes be heard when a rotor cracks.

I, too, am happier with KNS 1 piece rotors than the standard Napa ones.

hanseng1

Carbotech XP10s. This is the second set of fronts I've had this happen to, both with XP10s: first set lasted two weekends, second set lasted one short weekend.


I always run a full cooldown lap without touching the brakes, and rotate the wheels 90* several times after parking (usually 5 minute intervals, roughly speaking).

hanseng1

Been there. First track day I split some "fancy" drilled rotors. Noticed five minutes before my final session. Had the pleasure of driving home through Atlanta traffic on em. Learned quick to pass on the drilled rotors......

spearfish25

The benefit of the thirsty Z06 is that every single session I burn 12 gallons of fuel. There's not enough left for a second session so I have to come off track and immediately drive to a gas station 3 miles away. Nice extra cooling time since the road is a 50-60mph stretch without stops.

NVR2L8

150 MPH going into the "hog pen" at VIR !!!

Nowanker

Standard rule of thumb, if it extends to the outer edge, garbage. On a drilled disc, when you can 'connect the dots' between holes, done.
Others, it's a pure judgement call. If it looks deep and it's close to the edge, I'd trash it.
I like the concept that if you can catch your fingernail in it, it's close to done... that sounds like pretty good advice!

Dirk Miller

I drive a '08 C6. There is just something great about those Raybestos ST43s! They really have good feel, work well for a long time and are easy on the DBA slotted rotors I've used now for 5+ years. Hoping everyone out there has found them.