Cross Drilled Rotors...

[Brian2by2]

Please delete.

 

[nsxtasy]

All rotors can crack with track use - cross-drilled rotors, slotted rotors, and solid-faced rotors. Ask me how I know.

It's imperative to check the surface of the rotors before and after each track session. After a while, small hairline stress cracks appear; this is not a serious problem. Yet. With additional track use, larger cracks - usually in the radial direction - can form. As soon as you can feel the crack with the edge of your fingernail (NOT when the rotors are hot!), it's time to replace them.

The cracks are actually worse when the car is cold. When the car goes out on the track, the rotors expand with heat, and the cracks fill in. They widen once the car comes back in and the rotors cool down.

It's highly likely that the rotor problem cited in the above post could have been averted by a close inspection of the rotors prior to that track session.

 

[ncdogdoc]

According to the Brembo representative at NSXPO '03, crossdrilled rotors are designed for street use only, because they do not get hot enough on the street to create the cracks in the first place. Due to the extra cooling capability of cross drilled rotors, the surfaces cool much faster than the insides, resulting in much greater heat stress on the metal, and therefore cracks.

I would have to say that just having crossdrilled rotors would not create enough of crack to cause an accident. I think the rotor would have to be very thin or of poor quality to actually crack enough to cause a course change.

One of the cars at NSXPO cracked a spoke on his rear wheel, which gave him quite a shudder, but not enough to wreck him.

 

[Zanardi 50]

I purchased a set of Baer Eradispeed x-drilled AND slotted front rotors for my S2000. To my surprise (and dismay), both rotors cracked with JUST ONE USAGE - from the edge down thru the cross-drilled holes - after only 15 - 20 min. of spirited canyon driving (that's still street driving isn't it?). And yes, the rotors NEVER seen track. The Tire Rack (vendor where I purchased my rotors from) was hesitant to replace my rotors under warranty and instead tries to sell me another set! What the heck?? This is outrageous! Arrrgh, screw it! It's only $300 bux plus tax and shipping, not worth my time and inclination. Chalking it up as lesson learned (the hard way).....

 

[Zanardi 50]

BTW, slotted (only- not drilled) rotors are non-issue. I've got a set of rear for the S2000 and after having them on for a week, along with new pads (EBC Red Stuff - good stuff!!), they're grrrreat! No cracks or warpage (yet) after 3 trips to the canyons. Highly recommended. Just stay away from drilled rotors and you're gonna be fine.

 

[Yellow Rose]

Just stay away from drilled rotors and you're gonna be fine.

Be sure you let Porsche and Ferrari (Brembo) know this. They are probably so far back into the technology dark ages, they haven't a clue why drilled rotors are OEM items on their production cars.

 

[Lud]

Rotors can also fail catastrophically. For example if the center of the rotor (the part that bolts to the hub) separates from the outside of the rotor (the part swept by the pads), bad things can happen in a hurry, particuarly if the driver is not very skilled at car control in extreme situations. Perhaps this is the type of failure being described that led to a wrecked car. Typically this only happens with heavy track use and it is not particularly common, but I know 3 people who have had it happen with stock NSX rotors (not drilled).

 

[Arata]

There is a difference in quality from brand to brand.
Simply becasue one brand has failed does not mean all brands will.

 

[ChrisK]

I don't know if anyone cars, but I used Bembo/Bradi X-Drilled rotors on my Acura Legend for years with no problems at all. I got about 20K miles on them before I sold the car to my sister and she still has them on the car.

 

[Zanardi 50]

*Ahem* Silly me, I assumed everyone here knew what I meant when I said that. I wasn't specific enough. Please allow me to rephrase it again:

- Just stay away from BAER ERADISPEED X-DRILLED ROTORS and other similarly inferior aftermarket rotors and you're gonna be fine. -


Satisfied?

 

[ncdogdoc]

[Be sure you let Porsche and Ferrari (Brembo) know this. They are probably so far back into the technology dark ages, they haven't a clue why drilled rotors are OEM items on their production cars.

So if Ferrari and Porsche drive their cars into walls, would you?? (Oh, someone did here )

Did you happen to notice the mention of not OK on track cars, but they are OK on street cars. I guess not.

 

[RP-Motorsports]

Just stay away from drilled rotors and you're gonna be fine.

Be sure you let Porsche and Ferrari (Brembo) know this. They are probably so far back into the technology dark ages, they haven't a clue why drilled rotors are OEM items on their production cars.

Andy did you ever bend down to look @ a factory Brembo Porsche rotor? Or are you only good at talking about stuff you don't know nothing about and ripping on everyones posts? Ever wonder why you hardly ever see a drilled rotor on a true race car??? I think Porsche uses drilled, for noise and vibration prevention. Drilled is better than solid. Slotted is better than drilled, but for a street production car, slotted would be too loud, too much vibration, and would eat soft street pads too fast.

Fact. Porsche factory OEM drilled rotors crack. I see tons of 911's every year and I look at every cars rotors and most ARE cracked. A BMW M3 actually cracked a OEM rotor at 120 mph down the straight at Road America this summer and shot rotor chunks 50 yards into the paddock! I agree with Ken. I have personally cracked every single rotor design on my cars. I have also seen Ken crack sev. sets of OEM's too. True slotted will last longer w/o cracking than drilled, but only about 3X longer. Cold treating helps but still not crack proof. The best suggestion is to get the thickest rotor that your caliper can take,use a 2 piece rotor, make sure solid or slotted only, and install as much ducting as you can.

Oh yeah by the way at least 50% of aftermarket rotors that I see on cars, have the rotors installed with the L on the R and vise versa!!! Make sure you have them on correct, to let the vanes inside do their job.

 

[nsxtasy]

for a street production car, slotted would be too loud, too much vibration, and would eat soft street pads too fast.

On my NSX, I've used solid, slotted, and drilled. I have not noticed any difference among the three in loudness, in vibration, or in pad life.

True slotted will last longer w/o cracking than drilled, but only about 3X longer.

Not based on my experience; they have all lasted about the same - typically 600 to 1200 actual track miles.

I am currently using two-piece Stoptech rotors (slotted), and am hoping that they last longer than one-piece rotors. If they do, it will be because of the two-piece design. My one-piece slotted rotors lasted roughly the same number of miles as one-piece drilled rotors and one-piece solid-faced rotors.

I have come to the conclusion that, with track use, rotors are simply a "consumable", something that you expect to change frequently, just like brake pads and tires. Some of my friends using big brake kits have found the same thing to be true. You can try to improve their lifespan with measures like air ducting and two-piece rotors, but you're still going to be replacing them regularly if you keep going to the track. Put 8700 actual track miles on your car, and you'll be on your 11th set of front rotors (and never have to change the rears). Lots of laps, lots of pads, lots of rotors. Such is life.

 

[RP-Motorsports]

I went through 1 set of front rotors each season on my Teg.

I did get a couple more events out of the slotted -vs- the drilled

Slotted rotors ARE louder and eat pads faster. -----> maybe you just baby the pedal!!! jk

You are right Ken..... load up the trailer (or front seat in your case!) with tires, pads, fluids, and rotors!!!!!!