i was lookin online today and found these was thinkin about buyin em wut do u guys thttp://www.nopionline.com/nopistore/dsp_parts.cfm?vpcid=480&vcatid=0040&vcatyear=2005&vmodelid=578&vmakeid=135&vL1id=0&&vtitle=CHEVROLET%20Cobalt%202005

Crossdriled are prone to cracking, especially when they are sloted as well. Yes, performance is nice, but not long lasting at all.

dam thats a old wives tale


ive had drilled rotors on my g/fs cav for over 3years , and she is hard on brakes , and not 1 crack


the newer rotors are made with better materials , and better technoligy , and arent prone to cracking like the older stuff was

Are they just cross drilled or slotted also? That was just something my father passed on to me, so I never looked into them to the full extent.

I have heard most shops won't turn the rotors so if they warp you need to replace them. I have heard that you can have them turned but it's a difficult job and most shops just won't do it.

My previous car was an 03 Eclipse GT and I warped the factory rotors within a month of use.. I noticed the rotors were warped (caused shaky steering when braking hard) directly after the first snow when my car was new.

However, I immedietly replaced them with slotted and x-drilled rotors. I ran on the same rotors until I sold my car (a total of about 3 years and 70k miles). Never warped or showed any sign of wear at all. They eat break pads like crazy though. That's a major warning. lol.

Good to know that they're available for the Cobalt. I might be replacing my factory rotors come winter. :cry:

While there are many rumors and home made theories about the benefits of different rotors, lets try to dispel them and deliver some facts. Cross drilled rotors have long been the subject of ridicule and blame. For years many uneducated people have been blaming poor old cross drilled rotors for failures that were not directly related to them.

Cross drilled rotors were designed with the intent that cool air would pass through the rotor to help reduce the heat deflection through the rotor. An interesting fact about (all)"vented" rotors is that they pull air from the center of the rotors and allow it to pass in an outward direction. By cross drilling the rotors, you can achieve more cool swept area of the rotor and pad while sweeping the pad and rotor surface at the same time. This is very beneficial for performance and daily driving. The cross drilling also makes the rotor surface more aggressive to give a better initial bite under heavy breaking. Many people believe that all cross drilled rotors are prone to cracking. One of the things that they don't understand is that all rotors are prone to crack given wrong or extreme conditions. The difference is the heat threshold that each of these rotors will allow.

Just because a rotor is cross drilled does not mean that it is at risk to fail or crack. Many manufacture's use different methods to help prevent rotor failure. One such method is to radial chamfer each gun drilled hole in the rotor surface. This as you may recall from physics class makes the edge stronger, (a curved surface is stronger than a flat one). By doing this you also make the rotor more aggressive with out making them more abusive toward the pads. This also allows for more air surface for cooling.

Slotting the rotors is generally intended to pick up where cross drilled rotors leave off. They tend to have a higher thresh hold to heat there for enabling the brakes to function at much higher temperatures. By slotting the rotors you create "sweep" for the pads. At high temps cross drilling becomes non effective. Rotors can't pull air through after extreme temps. The rotor actually becomes a heat sink. As the cross drills become non effective, the slots can sweep the gas pocket out.

I will say my peace here.... Owning a vette as well, I hear alot of hype about slotted and cross drilled rotors on the corvette forums. I can count many many times where cross drilled rotors have cracked, proven with photos. They also claim to stop your car quicker, not true in my books. The corvette guys that autocross stick with the cheap 25 dollar napa or equivilent solid rotors. Cheap to replace and provide the best stopping power. More surface area for the pad to contact equals better stopping power period. If you want the bling bling, go with the slotted/cross drilled etc. If you want the best stopping power, go with the solid rotor. I have tried both, and there is no comparison.

when i was a tech for chevy , i saw alot of the stock/stock replacement rotors cracked

guess what no holes

its not all about surface area ...the slots help gas that is created by heat escape instead of pushing back against the pad ... I would go with slotted rotors but not a combo

I'm waiting for the Baer replacement rotors....Decela rotors :)

DecelaRotorsTM...our new line of direct replacement, cosmetically upgraded rotors. Designed for a variety of domestic and foreign vehicles, DecelaRotorsTM provide that dynamic race look without the cost.
http://baer.com/baer/xtra/img/decelalogo.gif
DecelaRotorsTM feature:

Dynamic visual impact
Superior bite
Equalized pad wear
Consistent wet weather performance
Direct OE replacement
The same counter-rotational drilling used in professional racing
Designed to eliminate outgassing while minimizing stress cracks

or a GOOD 2 pce Rotor
http://baer.com/baer/xtra/img/eradispeedplus_rotor.gif

I have never had a problem with baer brakes and rotors... :cssNET:

that's why my SRT-4 has rotors big brake kit.. ;)
Baer doent make anything for the SRT.

I have seen a lot of race car rotors and while most of them are not crossdrilled, 99% of them are slotted i.e Nascar, F1, Indy etc.... On the Very top of the line Mercedes and Porches there are usuallly slotted/ crossdrilled or any combination of the two installed. Apparantly these engineers that study brakes (and get paid good money to do so) have found something that some of us just dont understand, and dont want to. If i am not mistaken the new Z06 has brakes from the factory that are Slotted and x drilled ( i think they are an option, but i know you can get them from the factory)

This is just my $0.02

nope Z06 2006 brakes are slotted and xdrilled FROM THEFACTORY, take that and smoke it, lol

Actually most will tell you dont xdrill if you are using them in heavy competition, for street and occasional track duty it is fine!

The cross drilled rotors were put on the C6 Vette (Z51) and Z06 for purely cosmetic reasons because that is what is popular for a racy look.

While cross-drilling rotors aid in cooling, it also reduces the surface are of the brake disk that makes contact with the pad due to the holes, thus negating whatever effect the cooling had. So there is really no advantage to cross-drilled brakes!

The cross drilled rotors were put on the C6 Vette (Z51) and Z06 for purely cosmetic reasons because that is what is popular for a racy look.

While cross-drilling rotors aid in cooling, it also reduces the surface are of the brake disk that makes contact with the pad due to the holes, thus negating whatever effect the cooling had. So there is really no advantage to cross-drilled brakes!

Drilled and Slotted prevent fade and assist in wet driving aswell. I've run them for 6 years now. Not one, from any company have cracked. You must however buy them from a good manufacturer. Bear are the best, IMO. And yes, you could say that there is less surface to brake on. But, with a good set of pads you are already braking more effectively. With the buildup of gasses under the pad, resulting in reduced braking on solid rotors, you sacrifice good braking.
It's simply a matter of preference. I think they aid in breaking, others don't. Some just like them for looks, and nobody beats Bear in the looks department for factory replacements. Try them and give them an honest try.

Rotors and brake pads for all Cobalts!
http://www.cobaltss.net/forums/showthread.php?t=5703&highlight=rotors

crossdrilled and slotted DO aid in cooling - drilling STOPS cracks, not starts them - more than likely inferior material if more than "surface checking" deeper than approxiamately .020" appears



gm employee

just a fun fact; Baer filed for bankruptcy and can no longer buy anything on credit, according to the SSBC owner

nope Z06 2006 brakes are slotted and xdrilled FROM THEFACTORY, take that and smoke it, lol

Actually most will tell you dont xdrill if you are using them in heavy competition, for street and occasional track duty it is fine!


Thats what i said!