Vehicle: 2002 SLK 32 AMG, bone stock. 1987 190E 2.3-16 valve (destroyed). 1991 300CE, a work in progress.
Location: Near Washington, DC
Posts: 11,338
It's important to note the condition of the holes in the discs. They do not appear to be drilled, but rather cast in place. That is very important, drilled holes will have in most cases, stress risers in the center of the disc (in the vane area) that can lead to premature stress cracks and disc replacement. In severe cases they can lead to disc failure.
"Cross drilled" look good, and for most people that's enough, but if you track the car, you should consider slotted discs, as they have much fewer problems with stress build up and failure. Some think they look just as "nasty".
__________________ "Socialism is a philosophy of failure, the creed of ignorance, and the gospel of envy, its inherent virtue is the equal sharing of misery." Winston Churchill
"In my many years I have come to a conclusion that one useless man is a shame, two is a law firm and three or more is a congress." John Adams
"If you carry a gun, people will call you paranoid. That's Ridiculous..If I have a gun, what in the hell do I have to be paranoid For." Clint Smith, Director of Thunder Ranch
It's important to note the condition of the holes in the discs. They do not appear to be drilled, but rather cast in place. That is very important, drilled holes will have in most cases, stress risers in the center of the disc (in the vane area) that can lead to premature stress cracks and disc replacement. In severe cases they can lead to disc failure.
"Cross drilled" look good, and for most people that's enough, but if you track the car, you should consider slotted discs, as they have much fewer problems with stress build up and failure. Some think they look just as "nasty".
Since I am shopping for cross-drill rotors to replace the front cross-drilled rotors on my 190E, I was just wondering about a question that came to my brain. I am not questioning your statement about Drilling versus Casting the holes, but do you know if people actually buy the none drilled rotors and then have the holes drilled in then? Also this is not scientific, but from my search for cross-drill rotors for the 190E, I am finding very few, but the slotted type are readily available, so the cross-drill may be going out of flavor. The reason that I would like cross-drilled for the front is that the rear rotors (they are still within specs) are also crossed drilled, I think it would look funny to replace with slotted type.
"Cross drilled" look good, and for most people that's enough, but if you track the car, you should consider slotted discs, as they have much fewer problems with stress build up and failure. Some think they look just as "nasty".
I've heard that slotted may be better performance wise, but wear out your pads much quicker. The theory is that the slots "slice" off a small portion of the pads under heavy breaking, giving fresh material and better stopping power. This means they wear out faster. Drilled probably have the same effect, just not as severe.
Just what I've heard - I'm certainly not an expert in this area (or any area now that I think about it!)
Vehicle: 2002 SLK 32 AMG, bone stock. 1987 190E 2.3-16 valve (destroyed). 1991 300CE, a work in progress.
Location: Near Washington, DC
Posts: 11,338
Quote:
Originally Posted by bgoin
Since I am shopping for cross-drill rotors to replace the front cross-drilled rotors on my 190E, I was just wondering about a question that came to my brain. I am not questioning your statement about Drilling versus Casting the holes, but do you know if people actually buy the none drilled rotors and then have the holes drilled in them? Also this is not scientific, but from my search for cross-drill rotors for the 190E, I am finding very few, but the slotted type are readily available, so the cross-drill may be going out of flavor. The reason that I would like cross-drilled for the front is that the rear rotors (they are still within specs) are also crossed drilled, I think it would look funny to replace with slotted type.
Like I said, for everyday street use it doesn't matter if you have slotted, cross drilled, or just plain stock discs. If you are just street driving, and you bought drilled discs from someone on e-Bay that drilled them himself, to be honest, I doubt that you will ever know the difference. The deal is simple, street driving just doesn't pump anywhere near the heat into the disc that even autocrossing the car will. Track driving pumps still more heat into the discs, it's the heat cycling that causes the sharp edges of the drilled holes to start to crack. Those cracks get bigger each time there is another heat cycle.
Street driving just doesn't (normally) cause enough heat to start problems.
Quote:
Originally Posted by Rseegars
I've heard that slotted may be better performance wise, but wear out your pads much quicker. The theory is that the slots "slice" off a small portion of the pads under heavy breaking, giving fresh material and better stopping power. This means they wear out faster. Drilled probably have the same effect, just not as severe.
Just what I've heard - I'm certainly not an expert in this area (or any area now that I think about it!)
In many cases, sand is (or was) one of the components of a pads composition, as is fiberglass and a bunch of other very hard things. Next time you look at a brake pad, try and see just how hard it is, and then think how much pressure it would take to force that material into those narrow grooves to be sliced off......... It doesn't happen..
The pad MUST be in contact with the disc in order to provide friction. The slots and holes are there for one main reason, and that is to allow the gasses that form from the resins in the pad mixture at high temperatures a way to escape from under the pad. In racing the discs can get up to 1200 deg.F and sometimes more, on the street you lucky to get half that from a fast emergency stop.
Hope that helps.........
and about brake system..you will change it...i want install a AMG system with 4 pistons but i don't know where i can find it
It's two discs for front. Stock calipers and porterfield pads.
I was drolling over brake setup on Mercedes AMG F1 Safety car - compared to it - my setup looks like painted drums on Civic.
It's important to note the condition of the holes in the discs. They do not appear to be drilled, but rather cast in place. That is very important, drilled holes will have in most cases, stress risers in the center of the disc (in the vane area) that can lead to premature stress cracks and disc replacement. In severe cases they can lead to disc failure.
"Cross drilled" look good, and for most people that's enough, but if you track the car, you should consider slotted discs, as they have much fewer problems with stress build up and failure. Some think they look just as "nasty".
I was looking over the discs and couldn't tell if holes are drilled or cast - looks like outer perimeter (the notch type rim) of the hole is cast while the smaller hole may be drilled or finished touches applied by drilling it. But inside of the holes looks nice and shiny - that makes me believe they didn't came this way from foundry.
Anyway - i trust Brembo to engineered and manufacture good product - I am not going to track the SLK - so for the spirited street driving - these should be OK
The AutoGuide.com network consists of the largest network of enthusiast-owned enthusiast-operated automotive communities.
AutoGuide.com provides the latest car reviews, auto show coverage, new car prices, and automotive news. The AutoGuide network operates more than 100 automotive forums where our users consult peers for shopping information and advice, and share opinions as a community.
Linear Mode
