Cross-Drilled or Solid rotors: The Bottom Line Answers
 

Ok, there has been a lot of static in the forum regarding this topic. I want to know the final facts.

Particulars:

* Car MB: 300E
* Driving style: Aggressive - daily speeds over 90 mph (driving in Europe) Heavy usage of the brakes.
* Keeping the stock brake calipers, and thus, the stock size rotors
* Considering high quality (chamfered) Cross-drilled and/or slotted rotors
* Have heard that unless you increase the size of the rotor, cross-drilling merely reduces frictional surface area, canceling any braking benefits
* Have heard that slotted rotors eat pads and are non-functional gimick
* Have heard that stock solids function well enough, provided you couple it up with a high quality pad (e.g., Metal Master...)

Ok ... enough debate! What are the facts here? Let's go to the Bottem Line please.

Can anyone clear this up - in a straight forward manner?

Thanks,
David

I cannot, or shall I say, I will not attempt to get into this debate, but I can state my observations.

I have a 94 E500 with stock calipers and I bought some cross drilled rotors from KVR Performance (www.kvrperformance.com) for my car. I run PBR Metal Master Pads. I went with KVR becuase they were the only people that had cross drilled rotors that were OEM sized, they also have slotted or a combination of both. I did not want to change out my calipers and what not. KVR rotors are chamferred. I do know a few others that run these rotors with not problems.

For the record, I have an agressive driving style and I drive at least 85-90 mph everyday on the highway, though I have been slowing down to about 80mph lately as this is the time of the year I collect tickets. :D

I have been extremely pleased with KVR. I turned Carl from Bergwerks (www.bergwerks.com) onto these and he checked them out before I purchased mines and he said they were all good. They used quality materials. You may want to contact him for some more info.

Here is a pic of mines, though it is not a good pic as it doesn't show the rotors that much.

http://www.nemonis.net/shanta/wheels/1.jpg

I installed cross-drilled/chamfered Brembo rotors front and rear on a non-MB car I had a few years ago. I used the car for Monte Carlo style rallying in So. Calif. that involved a goodly amount of high-speed back road and mountain driving. I was experiencing serious brake fade and rotor warping with the stock brakes. The Brembo's, coupled with Porterfield R4S pads at both ends and Goodridge stainless brake lines were like a night and day difference. No more fade; consistent, solid braking performance, especially in the wet; and no more rotor warpage. I have to give a lot of credit to the Porterfield pads. They have excellent braking response at all speeds, even when cold, they hardly dust at all and they last a ridiculously long time for a performance brake pad. They're pricey, but a bargain in the long run. I would highly recommend them. I'll be putting them on my 300E in the near future.

Gary

Love your wheels Shanta !
 

One other consideration is Cryogenically treated rotors. I know of one member here that tracks his car and has used OEM, cryo treated rotors with good results.

I have purchased, but not yet installed some OEM, cryo treated and slotted rotors. Still need to get pads and refinish / rebuild the OE Porsche-Brembo calipers on my 500E.

Shanta -
Do you have the Porsche-Brembo aluminum calipers?
I can't tell from the picture.

I have the stock 94 E500 system which is the SL 600 brake system in the front. I may future wise upgrade my rears to the SL 600 system also.

Thanks for the compliment on my wheels. :D

That's right, forgot you had a 94.

Re: Cross-Drilled or Solid rotors: The Bottom Line Answers
 

1. better traction improves braking....get bigger tires.
2. drilling holes in your rotors reduces total swept area.
3. heat build-up is not a problem for anything but sustained track racing.
4. drilled rotors look cool :cool:

Re: Re: Cross-Drilled or Solid rotors: The Bottom Line Answers
 

yep...that about covers it. especially point #1

With cross drilled rotors, whether or not you track your car. Eventually, they will end up like this. Notice, this are chamferred

http://www.2phast.com/badrotor.jpg

I run slotted & cryo-treated rotors (320mm off of 600SL). The slots I do for looks-as I understand it, the brake compounds nowadays don't off gas like the old ones, so slots or holes are unnecessary from this standpoint. From a performance standpoint, solid rotors should be fine.

Cryo - plain & simple: it works! I ran cryo'd rotors for 20+ track days, and they never cracked...I'd still have them on the car if I didn't destroy them with a couple of sets of EBC Reds(VERY aggressive on rotors). Due to time constraints, I replaced them with slotted/non-cryo'd rotors, and they're toast after only 7 or 8 track days.

I've been on my rear slotted & cryo'd rotors for 3 years now, and they look as-new (my 600SL rear setup rtemains in the box, as the current rear brakes are completely adequate).

LMAO, "hit" the apex is the right word, even if backwards!! :D

That is why if you want holes in your rotors, get holes that are cast into the rotor, and not drilled, that way when the rotors are cast, the metal aligns itself around the hole which is much stronger, another cause for that is getting water on your rotors.

Drilled rotors do look cool I have them on my 300CD with 560SEL front brakes. I am trying out ate power slots on 500E front brakes right now, I will see if they really do cut up pads.

If drilled and slotted stuff was a bad idea brembo wouldnt do it. Look at their GT kit you can choose what you want.

Take it easy,

omegabenz

I agree with you on the cast part of " cross-drilled " rotors.

I remember talking to a Brembo rep. one time & he stated to me, nothing pisses Brembo off more, than some " tuners " buying Brembo rotors, cross-drilling them and then selling the rotors for twice the original cost.
Of course when the rotor develops cracks, Brembo gets blamed for it. :eek:

Zimmerman rotors (cast) and textar (yellow box) pads. Best combo i've ever used.