fhp911

Anyone know of replacement SLOTTED, not drilled, brake rotors for the 987??


TIA, CIA, etc,

Fred

KS-CS

dba (disc brakes australia) makes them but for the fronts only. Girodisc also makes a set (F and R) that are larger than stock (use a spacer). I have a set in my garage - just waiting for a day less than 100F to install them.

No HTwo O

If and when I need to replace rotors, I plan to have them cryo treated. Are you guys considering this too? Costs maybe $100 per set.....and last about 2x's longer????

TheKane

I've been tracking (and driving hard on curvy roads) and have 14K on my Spyder. I have aftermarket pads and fluid, but I don't feel or see any issue with the stock rotors. What are the benefits of slotted vs drilled, or other aftermarket manufacturers vs Porsche?

I have aftermarket rotors on other cars, but that's because I was noticing fade and cracking rotors. I haven't even warped the Porsche stock ones.

fhp911

IMO -- drilled rotors are less than ideal for track use because they promote cracking -- the cracks start around the drilled holes and travel between the holes and soon the rotor has to be scrapped -- at least that it the way it goes for GT3. [I owned one until this season -- admittedly the car is much faster and so needs much more braking.]

Slotted don't crack as easily, so they last longer. No reason to prefer Porsche over other brands, but there may be big savings available -- for the GT3 stock Porsche rotors cost $300 or so, versus what I could buy from Tire Rack for $130 -- and they last less than 1/2 as long! [final irony: the Tire Rack rotor is made by ATE and is the stock rotor for the Cayenne.]

KS-CS

And you likely won't "warp" the stock rotors; however, as fhp911 pointed out, you will get cracks with hard track use. When I started getting significant (e.g. 5-6mm) cracks after just a couple of track weekends on brand new OEM rotors, I decided it was time to switch to slotted for track use.

Bill Lehman

After replacing two sets of front rotors on my 2.7 and 3.4 Cayman due to cracks either connecting or going to the perimeter, I am trying the DBA slotted rotor. I now have 4 track days on them with no issues. The Thermo-Graphic paint says I am reaching 550 degrees C. Cost was $316.47 a pair for the Cayman S fronts from TopBrakes.com .

TheKane

Thanks for the info gents! I should have phrased my original question better, but you did answer the question I meant to ask. Sweet! I know the benefits of slotted vs drilled. I have to run slotted on my Suby built by LIC Motorsports, and even then I crack (all the way through a side) my slotted rotors every 5 months. I run aftermarket rotors, but since I can't swap in the big brake kit, and have to keep the stock size (for rims with studded nobbies for winter), I'll keep cracking them since they can't handle slowing the car with the engine/suspension work cone by LIC. I call it planned obsolescence.

You did answer my real question: "has anyone had problems (cracked/warped) the stock rotors?". The answer seems to be "yes". I've looked at my rotors, and so have SCarGo Racing (who replaced the stock pads and fluid), and even with my 5 track days and hard driving, I have no fractures. I'm guessing that the reasons for my lack of issues are (to a lesser extent) my braking style and (mostly) aftermarket pads.

Thanks again for the info on aftermarket, I'll probably switch to the cheaper/more durable when my current ones do need replacing.

bensf

Can you guys elaborate on the rotor issue. I checked my rotors this morning and have found 2 to 4 mm cracks radiating from the holes of my front rotors and I know they are still good, the rear rotors do not exhibit any cracks. The stock rotors have been through 12 track days but probably the equivalent of 10 since the first 2 were in the rain. Switched to aftermarket pad and fluid after the 6th track day and the brakes work great. They do not exhibit any fade in a 20-25 minute session. It looks like from the above posts that the DBA for the fronts is a good choice if sticking with stock size since they are the same price as stock rotors. What about the rears though since they don't seem to make the appropriate rear sizing?

I like the idea of GiroDisc and they look very cool but unless their rotors last 3 to 4 times longer than the stocks or the DBA's, they don't seem worth it. I'm also concerned about adding the spacer for the GiroDisc application and potentially bending the metal brake line when installing.

fhp911

The general wisdom is that cracks going from hole to hole are ok --it's when you get a crack which has traveled to the outside edge of the rotor that you MUST replace the rotors. At that point the rotor could shatter, with disastrous consequences.

KS-CS

I think most guys using dba's are going with the stock rotors on the rear, since the rears don't seem to crack as much anyway. I considered the dba's but from an aesthetic standpoint, I didn't really want to drive around with 2 different style rotors front and rear.

IIRC, the spacer on the Girodiscs is only about 1 cm thick, and I think there is enough flexibility in the brake line to accomodate that - at least, I haven't heard of anyone having any issues in that regard after installing them. I'll try to report back after I install mine.