cross-drilled rotors?

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That's why two piece brakes are common on racers so it makes it easy to change disks and they can choose lower unsprung weight. Some racers still like the drilled rotors but they crack and they last one race and get s-canned. Some ideas die hard....
I had slotted Racing Brakes on my NSX and I hope they make a two piece solution for the CL55. Smart engineers there.
Stock AMG brakes are awesome, but I'd like the 2 piece rotors when I have to replace them. Check out Racing Brakes.
If I recall correctly, Merc calls our non-AMG sport front rotors either perforated or ventilated; no cross-drilled. I've looked for my sources, but can't find anything...
Anyone else recall the same?
Their fleet of 80+ uses stock brakes (non-drilled) & gets flogged hard daily. The instructors says no problems with heating nor fading at all.
So I doubt if our E series gets that much racing abuse for need to upgrade to drilled rotors...
Their fleet of 80+ uses stock brakes (non-drilled) & gets flogged hard daily. The instructors says no problems with heating nor fading at all.
So I doubt if our E series gets that much racing abuse for need to upgrade to drilled rotors...
Not really. The theory about the outgassing from holes/slots is that they should allow for debris to be removed from the surfaces, keeping the pads cleaner and smoother. Common issues with them are usually related to less mass = more heat, combined with many inferior products out there. I did find that the Zimmerman/OEM rotors are cast with the holes, so the heat treating is uniform throughout the rotor, many aftermarket are drilled later which impacts the heat treatment and can also cause small chips at the edges of the holes. So be careful about price vs. quality.
Also, regarding warping vs cracking, put a laser temp gun on a rotor when you get home, you will be surprised how hot they not only get but how much heat they retain, even from regular driving. The heat sink part can be an issue if they hit cold water/rain, which can cause warpage.
I say anyone can use what they like but I prefer the solid mass rotors, good quality pads, and a brake system with regular fluid flushes. Other than looks IMO I just can't see a rational justification for drilled. Ventilated is another story, yes most everyone has them and they do a good job of capturing airflow into the rotor surfaces.
Last edited by Mud; May 27, 2015 at 03:11 PM.
Any noise I hear is the same for both front (drilled) and rear (solid) rotors and I would not describe it as grinding. Holes in rotors are not like a cheese-grater, they don't shave off parts of the pads. If they did pads would only last about 5-10K miles and in fact proponents of drilled rotors describe pads lasting longer, so I don't know the basis of your theory.
Noise is directly related to surface condition of the rotor and especially pad material, not holes. Semi-metallic pads can be on the noisy side, especially when cold and/or when first driven after the car has been parked due to accumulation of surface rust and any debris left on the pad. First few brake applications are essentially wiping the surfaces and building some heat into the rotors.
Anyway, there's not much more to add to all this. It doesn't really matter to me to be "right", I'm only trying to look at some evidence pro/con.
But the real evidence would be that engineers smarter than you and I are putting these rotors on the cars from the factory (MB, Ferrari, Maserati, Porsche, etc), so it's pretty obvious that they won't be a danger nor inferior in performance, whether use them for show or function. And I would highly doubt changing to a solid rotor alone would provide better stopping on street use. Now if one were to be tracking a car then obviously it would be wiser to use an actual track setup. Anyway, my point is, if MB used drilled rotors from the factory, you're not gaining anything by going OEM-replacement solid, unless you're going with aftermarket parts in efforts to save money. In another words don't reengineer the vehicle (unless you're modding).
Last edited by DJ Hellfire; May 28, 2015 at 09:20 AM.







