Contour Enthusiasts Group Archives Forums Modifications Brakes Great idea for brake improvement (question!?)

Originally posted by Bud Miller:

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Originally posted by Thinkmoto:

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Umm he wants to know if it's Carbon Fiber

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Sorry Thinkmotor, I guess I didn't understand the question. Kinda hard when he doesn't E-L-A-B-O-R-A-T-E. Anyway, I don't know anything about carbon fiber. What's that?

Bud Miller

=> No mistake, it's a Mystique <=

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it's Thinkmoto.... and you don't know what carbon fiber is???

Originally posted by Thinkmoto:

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.... and you don't know what carbon fiber is???

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Originally posted by HThomas:

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I don't see why every one is so sour grapes here. I think drilling rotors is a great DIY job. Holes are holes, right? What, you think some expensive mill can make some kind of hole that a hand drill and a titanium-nitride bit can't?

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Because he wants to take an "old" rotor, which means its probably already nearing the end of its service life due to wear, and drill holes in it. SO he will be taking a rotor that is already low on thermal mass, and removing more! And on top of it, he will be adding a large number of stress risers in the braking surface. The rotor will not be able to handle the added thermal stress, and will crack. And the fact that it wasn't designed to be drilled will likely make the crack a catastrophic failure (read, total rotor failure).

Holes are most certainly not holes. If you read what I wrote before, a proper drilled rotor is designed that way from the begining. That includes sizing the rotor to have enough thermal mass AFTER drilling. It also includes the hole size and chamfer size (which Bud fails to mention), the hole pattern (very important to prevent crack propagation), venting design and pattern (to prevent crack propagation and improve airflow for cooling).

So essentially, this guy wants to take a worn-out, stock, non-performance rotor and hack it up because he saw it on a Mercedes. All to improve a condition resulting from his BS theory about humidity?

And your friend is wrong. Panoz LMP cars run with carbon-carbon rotors (not steel), and they are non-drilled.

-Todd

Originally posted by Silver Snake:

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I now work for Brembo Brake Systems (you may have heard of us, we have a small reputation ). Mercedes does not use cross-drilled rotors as an OEM part. I know, because we make them.

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Originally posted by Bud Miller:

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Originally posted by Silver Snake:

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I now work for Brembo Brake Systems (you may have heard of us, we have a small reputation ). Mercedes does not use cross-drilled rotors as an OEM part. I know, because we make them.

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Head's up everybody! I think this SliverSnake guy might be a fraud! While all of you are spending your time trying to smear me and criticize my sincere inquiry, I spent a little time checking Mercedes Benz web site. Please take a moment to check this out: Mercedes S-series

In it, you will see none other than a drilled hole rotor photo on Mercedes S-series cars. The SilverSnake is correct that Brembo makes them, but he is wrong on the drilling holes. Maybe we need some proof that he really works for Brembo. By the way, isn't Brembo in Italy? If you work for Brembo, then why locate in MI? Very strange.

Otherwise, this isn't such a big deal. You guys don't like my idea of adding holes. Even if humidity isn't the main reason, there still must be some purpose. And nobody can explain why. And all this talk about thermal mass. What the heck is that? Heat weight? Who are you trying to kid? Heat doesn't have any weight. If you put a candle on a scale, it will weigh the same before and after you light it. Gimme a break!

OK. Time to cool down. Really, I like you guys, and I love to read this site. We should all get along better.

Bud Miller

** No mistake, it's a Mystique **

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I am a fraud, posing as a Brembo employee. Thats a great one. THere are people on this board who know me, including Worldtour and Rara. Rara has even been to my office.

Yes, our headquarters is in Italy, Curono Italy to be exact. I am flying there tommorow actualy, as I have meetings there all next week. I work in MI, because our office handles the North American OEMs. In case you can't follow that, North American OEM's are Original Equipment Manufacturers.....i.e. GM, Daimler Chrysler, Ford Motor Company, Nissan North America and Honda North America. We are based in Detroit (Farmington Hills to be specific) because that's where these manufacturers call home (with the exception of Honda NA, who is based in Marysville, OH). CHeck out www.brembo.com , there is a a blurb on Brembo's worldwide locations that will list our three North America locations. Like I said, our office handles OEM customers. Our Costa Mesa, CA office handles after-market kits and applications. We also have an office in North Carolina that supports the NASCAR teams using Brembo.

Now, as for the Mercedes rotors, I will admit I was wrong. Mercedes is handled directly from Italy (with the exception of the Chrysler platforms which we do). I thought that only the Mercedes AMG-tuned cars used x-drilled. My mistake, and I apologise.

You said there has to be a reason x-drilled is used, but no-one knows. THat is not correct, the reasons have been explained in more posts than I can count (if you would have searched, you'd find them). But since the search button seems to elude you, I will explain.

In the early days of disc brakes, the pad materials used to break down under the extreme heat produced during high-speed braking. They out-gassed, or released gasses from the pad material as the friction couple heated up. This gas was trapped under the pad, and cased a loss of friction in the brakes. The solution to this was to drill holes in the rotor surface to allow space for the gasses to go without causing a fade condition. Pad out-gassing was only seen under extreme braking, ie. racing conditions. THis quickly became the standard in racing brakes. As with anything race related, people began to emulate this look for the street (same as with wings, mag-wheels, power-bulge hoods, etc.).

Flash forward to the 90's and we have a whole new grasp of friction material science. Modern pads simply don't out-gas like they used to. The holes are not needed for this purpose anymore. Brembo and Porsche have done testing that shows that x-drilled rotors do offer increased initial bite in the wet (also called first effectivness). This is the only real gain shown. And for the record, wet means rain/puddle, not humid air. There are improvements in cooling time, and weight savings, but they are negligible. And ALL drilled rotors will crack faster than a non-drilled rotor. There are ways to prevent catastrophic cracking, but they will crack. Like I said before, a properly drilled rotor is designed that way, not just randomly drilled.

However, people still like the look. It has a "race" look to it. People buy image. We produce and offer drilled discs to all of our customers. In the end, it comes down to marketing...99% of the time. In fact, look at Porsche, Ferrari, Mercedes AMG, Lamborghini.....all of these customers uses drilled discs (all except Porsche use Brembo discs BTW...they just use our calipers). However, all of them run solid faced rotors on their factory race teams. All of them, the 911-GT2's that sweep Le Mans yearly. The F360's run in the Ferrari Challenge races. The AMG Mercs that rule the roost in touring car racing. Even the Lambo Mucielago-GTR that is set to run in FIA-GT this season. They do this because its better.

Lastly, I will address your issue with thermal mass. First, lets understand how a brake system works. The purpose is to turn kinetic energy in to thermal energy. Period. Tires stop the car, brakes stop the wheel by converting the enegergy in to heat. The puspose of a disc is to act as the heat sink. The more iron in a disc, the more mass to store heat. THis is refered to as thermal mass. Once a rotor has accepted too much heat, the heat is passed to the pad and the fluid. This causes fade. A larger, thicker rotor can store more heat than a thinner totor. More thermal mass. THis is what prevents/reduces fade. Pick up a good themodynamics book to understand it better. Or better yet, go to Barnes and Noble and pick up The Brake Disc Manual.


Its written by Brembo. It will teach you more than you ever wanted to know about Brake Systems.

My last note on this subject will be this...

Two weeks ago, I replaced the calipers, rotors, and brake lines on my car. I upgraded to all Brembo equipment. Due to my job, I get my parts free. Despite the fact that they were free, I chose solid rotors for my own car over the "bling-bling" expensive drilled ones.

I am sorry for comming across abrasive, but you essentially called me a liar and a fraud. I also hate to see misinformation spread, especially on a safety critical item like brakes. If you want to know more, shoot me a private message and I will give you my work email/phone.

-Todd

PS. No hard feelings.

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And your friend is wrong. Panoz LMP cars run with carbon-carbon rotors (not steel), and they are non-drilled.

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You will develop stress cracks where you drilled.

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