jangy

Do you have another source for the slotted rotors? Thanks for the PM.

SLK55R

Yeah like I said ... mercedes ... mine are cross drilled and slotted. 030 package.

adx

Correct, EVO rotors are not cryo'd. I got them cryo'd at www.300below.com and it cost about $150 for all 4 rotors.

L8Apex

Tirerack carries Brembo slotted rotors. Not sure if they have them for our cars though.

FlyByNight

I'm curious.. if drilled rotors crack like this... and slotted tend not to (other than shatter)... does a cross drilled AND slotted rotor fare better or worse crack-wise over the long haul? I would imagine worse since you're adding yet another wrinkle to the overall struture, but who knows.

I've been holding out for good aftermarket cross drilled and slotted rotors for a while now...



Loren

mbbodytech

To quote the WIS: (workshop information system)

"Ventilated, brake discs with perforations and without perforations do not have to be replaced if the hairline crack length is a maximum of 25mm.

On perforated brake discs the hairline crack length including the hole diameter is to be measured"

So, the discs don't have to be replaced if there is a crack, however if it looks like the picture above I would replace them in a minute!

jangy

No they do not. Brembo was the first i checked. There is a possibility that they will make a group buy if enough people commit. They do offer a package that includes calipers.

saveur

Actually, I wouldn't be too worried about these hairline cracks. They're mostly superficial, and just comes from fairly hard use (but intended use). I have many hairline fissures on my 996TT, which are still using stock rotors. I track the car quite often. Like the other poster mentioned, if they are beyond a specific length/depth, then that's when you need to replace them.

C43AMG

Have you ever considered taking the front wheels off and "punching out" the buildup in the holes of your rotors?I did mine on Friday - just for the heck of it and was blown away with the amount of garbage that came out.I used a philips head screwdriver and then used my compressor to blow the holes out and the vanes on top.If the design of the holes is to help disapate heat they can't do the job if they are partially or completely plugged.

pas

Have you noticed any difference with the rotors being cryo treated? Have you braked real hard from high speed repeatedly or done anything to "abuse" the rotors that might lead to surface cracks? I was told by the guy at 300 below that cryo treatment would solve the craking issue with the stock rotors just wondering if you have any actual experience to back it up.

Thanks

adx

I just had the rotors installed about a week ago so it is too soon to tell. However, I will be driving down to San Diego for Labor Day weekend and will test these new rotors out at high speeds. By the way, will be getting the Renntech lowering module installed when I get to San Diego.

mertd93

Well in case you didn't know you have 2 piece floating composite rotors made by brembo on your slk55.

vixapphire

yeah, but those turkey platter-sized brake discs sure look cool from the kerb at stoplights, don't they?

guanabara

Dude you would think that the holes would be helping in reducing heat Huh?
It looks like your rotors are cracking by a combination of structural degradation by the holes plus an apparent overheating.
Are you using the brakes too hard all the time?
Are the metal surfaces that make contact between the pads and the caliper bracket well lubricated and cleaned up of rust?

I recommend you try the new rotors that have dimples instead of holes.
I have seen one that had dimples and slots. It looked nice and reasonably priced.
I just had my front pads replaced today. I used Akebono's ceramic pads.
The original rotors still looked good (no lips) and quite shiny so I left it alone.

E55 RUSS

I had this...replaced them at 25 km...They are not that expensive...I think it happned after you get you brakes hot and then hit water splash or clean you wheels with chemicals...

guanabara

another thing you have to consider is that given the high cost of some of these rotors, there is a posibility that depending on where you buy your parts you could be get counterfeit stuff from Northern Asia, if you know what I mean. Those rotors don't come with serial numbers or fancy stickers that let you know when you have been taken.
Try buying these parts as anything else for your cars from reputable dealers such as tirerack or any others that advertise here.
I would stay away from ebay and other shady fly by night web sites.
You would never know what you are really getting there.
Your car costs enough for you to be trying to skimp on a few dollars on parts.
Specially when you are already saving a bundle on DIY stints.
Have a great one

guanabara

Nice "wheels" by the way Russ. Congratulations

tigerlam92

I had used www.300below.com many years ago to cryotreat my Baer rotors. You can have the rotor send there straight then treated before coming to you. Would I do it again, NO. After road racing for four years and getting my professional race license, I would still not do this. Most people at the track will put in the biggest but cheapest rotor you can find. Then replace it when you need to.

Back to topic:
As stated, the cracks looks fine to me (some starting to look pretty deep and big though). I would not hesitate to drive it at all. I have raced rotors that look like that. I would only worry if it has cracked through and extend to the end.

iolithblue

someone mentioned that brake rotors seem to be made out of any old pig iron.... indeed thet are as cast iron provides the best heat dissapation/ duarability mix needed to survive this much abuse for this long. think about it.
assuming a perfect system, your car can stop quicker than i can accelerate, meaning your car has more "stopping horsepower" than "acceleration horsepower" any yet only your engine has a dedicated active cooling system, not your brakes...