Which Brake Rotor?

[Big Daddy]

I am going to replace my front rotors on the M roadster. I have two options that I am looking into. The first is Brembo's, standard rotor, under $50.00 each. The second is ATE's, gas slotted, $75.00 each. I use the roadster during nice weather only, and my driving is "spirited". I am no longer tracking the car. Should I spend the extra $50.00 for the slotted...that is the way I am leaning?

 

[shadymilkman]

I say no. If you're not track racing, your driving has to be pretty damn spirited to actually see brake fade in the brembo rotors.

 

[mjbst111]

If you aren't tracking anymore and don't have to be stock to stay in a 'class'....

I would do ATE's if you ever plan on driving over 100. (Don't know exactly what you mean by spirited.) If even once its neccessary to stop quickly at high speeds, you will thank yourself later.

i've experienced brembo rotor fade..

Then again its a totally different ballgame in an //M huh?!

 

[Zee3Coupe]

Big Daddy, why did you decide on the ATEs versus other drilled or slotted rotors? Cost? Performance? I've been considering slotted rotors myself and end up getting dizzy by the number of options each time.

Also, maybe you can explain to me why everyone says that drilled rotors are worthless because they crack and rust like crazy, and yet every Porsche, M3, and Ferrari has them? Thoughts?

 

[Big Daddy]

Daniel For the M roadster the options are limited. I used ATE gas slotted on my 91 318is and really did not notice any big difference in braking. I trust ATE as they have a great reputation. All the professionals agree that drilled are going to wear your brake pads out faster and are more prone to cracking, and not that I would but you cannot turn slotted or drilled rotors. Those Porsche and Ferrari guys just replace them more often. Some professionals are telling me that with today's brake pads slotted are not necessary and that with everyday driving you are not going to see a difference.

Michael I was not tracking the car in any class, I was using it for BMW CCA High Performance Driving Schools and Safety Schools. I no longer participate in these (with this car), but still push my car to the limits at times. I was only considering slotted for two reasons, looks, and the rain we experience here in the Pacific Northwest. I am not sure the extra $50.00 (total) in costs is worth it though.

Shawn I agree, as I said above in this post I was looking at two benefits, looks and wet braking. Any more ideas guys? I am still mot 100% decided?

 

[MrElussive]

Spend the extra loot for the better product. I know that a $50 difference out of a $100/$150 purchase is significant, but $150 for a pair of rotors isn't that much.

 

[epj3]

Dan, the rotor won't make your braking improve as much as putting that extra $50 into better pads. I went from oem rotors/pads, to oem rotors and Pagid red's. Never ever had ANY fade (this is in my 325is) and that was driving like a nut on back farm/mountain roads in williamsport. I then went to slotted ATE rotors with the same pagid pads (new set), never had fade, and honestly I thought the solid rotors were better... the initial 'bite' was better too.

 

[Big Daddy]

I am not sure the "better product" is the ATE's? It is hard to beat Brembo rotors, I am sure the ATE's are $50.00 more because of the slotting.

Eric, I have been using EBC's "Red Stuff" pads. From HMS Motorsports web site: "Red Stuff Pads are suitable for high performance street driving and autocross. Ideal for everyday use in high performance vehicles such as M Roadsters, M3’s, 328 and 330 models. This is also the pad recommended for all heavier cars such as 5 and 7 series. Squeal free and nearly dust free!
EBC's semi-metallic Redstuff formulation is a high performance street pad with medium lifetime and a friction level of about 0.3µ steadily rising to 0.33µ at 750ºC. Redstuff is very kind to brake discs and can be used on highway vehicles for high performance and extreme duty use. Redstuff gives longer pad life under extreme road conditions features and benefits: friction co-efficient starting at 0.3µ and rising to 0.33µ once warm
medium initial bite with friction steadily increasing with heat heat stable to an incredible 750ºC low disc abrasion"

 

[Big Daddy]

I ordered the Brembo's. From what I can tell the slotted would accomplish me nothing, other than looks. I will let you know what I think when they arrive.

 

[Pete K]

The first couple of times I took my car to the track (NHIS) I warped the rotors. Makes for an expensive weekend. Then I had ATE drilled rotors put on the front. No fade at all but they did warp just a little bit. Of course, NHIS has some really harsh braking zones. For everyday "spirited" driving the stock rotors would be OK for me though. Just my thoughts...

 

[Big Daddy]

Thanks for all the input, I went with the Brembo's and they arrived a few days ago. I will be putting them on in a few days and let you know what I think. $50.00 ea. shipping included was a great buy!

 

[IslandDawgZ4]

Dinan says slotted

The new R&T has a Tech response on this issue and it seems that they think slotted are best since they dissipate brake gases quicker and thereby reduce fade. I don't think they like harder pads particularly either. Drilled are basically dress up goodies.

There is an article in The Rondel, January I think, in which Steve Dinan, goes through an extensive upgrade of a Z4. In the article, he fully explains the differences in rotors and his preference for slotted rotors. These are thing he should know about. I'd consider him an "expert"!

 

[davidmj]

id go with the ATE gas slotted i got it and its top

 

[Big Daddy]

Here is some information I found that seems very true and helpful:

For many years most racing rotors were drilled. There were two reasons -
the holes gave the "fireband" boundary layer of gasses and particulate
matter someplace to go and the edges of the holes gave the pad a better
"bite".

Unfortunately the drilled holes also reduced the thermal capacity of the
discs and served as very effective "stress raisers" significantly
decreasing disc life. Improvements in friction materials have pretty
much made the drilled rotor a thing of the past in racing. Most racing
rotors currently feature a series of tangential slots or channels that
serve the same purpose without the attendant disadvantages.

the process of drilling rotors and slotting rotors was done for 1 reason
and 1 reason only it is to disipate the gases that build up between the
pad and the rotor which occurs under extreme heat ( when braking very
aggressively like on a road course) and it has absolutely nothing to do
with heat disipation. the only way to transfer more heat away is by
using a larger heat sink which means use of a larger rotor whether in
diameter or thickness. Since the caliper will only allow for a certain
rotor thickness that solution is not very applicable because, if you are
changing tha caliper opening width you might as well get a larger rotor
diameter at that time.