Wondering if this is a bad idea. My mechanic assures me it's safe for both the pads and the rotors and there won't be any extra wear or warping. But I've heard from a few people that you shouldn't use full metallic pads with slotted or x drilled rotors. Which of these is true? I am currently running full metallic pads with slotted rotors. Thanx for the info!

 

stillen's level 1 brake kit is the slotted/or xdrilled
and they recommend metal matrix.
so i guess it can't be that bad
Vic

 

Slotted and cross drilled rotors do nothing ***POSITIVE*** anymore except look cool. Therefore, i don't think it would matter what kind of pads you use with them. Also: vic, bring back your sig... cool sigs like that should be not only legal, but encourged.

[Edited by theblue on 01-31-2001 at 11:59 AM]

 

The statement above notwithstanding (translation: inaccurate), metallic pads will 'eat' away at your rotor surface, causing them to get thinner. This means your rotors will actually get thinner the longer you use metallic pads.....metal grinding metal is great for stopping but will wear your rotors down over the long haul. But this process is so slow and gradual that you would probably warp your rotors long before these effects could be felt or seen.

What sucks about cross-drilled/slotted rotors is that you can't turn them, so theoretically they won't last as long as blank rotors given metallic pad use. Wearing these type of rotors down will occur faster, especially for slotted rotors. Once the top rotor surface wears down to the bottom of those slot grooves, it's time to replace the rotors.....

Cryo treating only prevents premature warpage....it does not prevent metallic pads from wearing down your rotor surface....


[Edited by bill99gxe on 01-31-2001 at 11:26 AM]

 

Nope, I said nothing inaccurate. While everything you said was true. I did not say that metal pad are better. I thought it was obvious that metal pads will wear rotors faster regardless of what kind of rotors you have.

 

is inaccurate.

There aren't really doubts as to whether these types of rotors perform better, but by how much over blank rotors. That is another thread discussion entirely.....

I edited my previous post to illustrate what I thought was inaccurate.....

 

I edited my previous post to illustrate what I thought was inaccurate.....

 

First though, I have cross drilled rotors on my 95 GLE and now have just about 30K on them with no problem.

CROSS DRILLED, SLOTTED, VENTED ROTORS

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 so called racers 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 wanna be "Racers" 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.

A slotted rotor will have a higher thermal thresh hold but can still fail. One of the most overlooked reasons for brake failure is mismatched pads and rotor combination. With out the correct combination, your performance level could
really be at risk as well as your safety.

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. For a real world example, look at "real race" cars. Mainly, road race cars such as Trans Am, IMSA, and CART will exclusively run slotted rotors with very aggressive pads. While many teams have their particular love of brand, they all have the same basic function. One must also realize that when operating a performance system, there will be a trade off in the system some where. Generally performance street systems are designed to compromise the pads life with added braking ability. By doing this, one can expect certain "better" braking while not sacrificing the life of the rotor.

As you move up in pad compound, you must realize that it takes more heat to get these brakes working at optimum standards. The trade off here is accelerated rotor wear.(Here's were combination playing can pay off / or not). Ideally, you would want to run a new pad on a used rotor and vise versa when seating new components. Depending on the track conditions and characteristics of the particular car, bypass stagger (brake ballast) in conjunction with pad and
rotor combo can be the deciding factor in longevity and performance.

For most import and domestic applications, there should be little more than a need for basic cross drilled or slotted rotors with carbon based pads and steel braided lines. Not all big brake kits are practical for each application. They
may not even be available for your car or truck. The last important factor is to take into consideration is driver charctoristic's. Late braker's will generate more heat cycles than a "two footed" driver. The dreaded "two foot" driver will just eat brakes - period.

Regards

 

I disagree with your statement that you cannot turn slotted rotors; I have first-hand experience to the contrary. My rotors are NOT the gold cadmium plated ones, they are just plain carbon steel. I would think that the plated ones are not machineable because of the plating, not the slots.

 

I contend that you shouldn't turn slotted rotors because of WHO turns them, not because you CAN'T turn them. There's a difference.

As you know, most places that turn rotors don't have the proper/most up to date equipment to do them correctly. With slotted rotors, any variance from smooth is bad news for your brake pads as well as your teeth when braking. So, if one slot section is raised higher than it should be, then those brake pads will be toast in a hurry.

I doubt, though I don't know for sure, that cadmium plating, or even painted cadmium plating, has an effect on the ability to turn a rotor. Since most rotors that have the coating aren't blank ones anyway, I don't have any experiences to back up this claim.

The only thing I know about cadmium plating (aside from rust prevention) is that you can still cryo treat rotors with this plating, which actually surprised me.....