Rotors on eBay

W

WaZZZZman

Active member
 Over the rainbow near the emerald city
It is me again with my brake rotor problems. I asked if anyone knew where you can get rear brembo rotors for my 2004 Z4 2.5i. Well according to the brembo web site they do not make them so I guess I answered my own question. I want to get new rotors and pads for my Zed and wanted drilled rotors as most of the better high performance vehicles have them and keeping with my rule of only doing mods that are true improvements I wanted to get higher performance brakes. :?

Now knowing that I can not have brembo all the way around, I have a couple of questions for the smart guys and gals out there. 1. Can I put brembos on the front and some other brand on the rear? 2. There are some drilled rotors and pads offered on eBay. Anyone have experience with any of them and is Muhsyn Motorsport in Salt Lake City any good if you have had experience with them? They are big on eBay.

I was looking at R1 Concepts but they do not appear to be on eBay any longer and have I have read some bad reports about them rusting and other problems in regard to support and quality.

Does anyone know where I can get a good set of rotors for about the same price as brembo? :cry:

Thanks for any help you can give me. :)
 
Wazz, do you specifically want drilled/slotted rotors?

I really don't want to start a flame war here but, 99% of the time, drilled/slotted rotors are a waist of money unless you want the 'Look'.

The original D/S rotors were developed because, at the time, the pad material would 'outgas' and create a gas layer between the pad and rotor surface and to lighten the rotor. This was the main reason. There are others reasons also but are very minor.
Now with the newer pad material the outgassing is pretty much a thing of the past....

Drilled rotors also have a 'fatigue' factor. They are not as strong as a solid rotor. You do get a SMALL cooling effect but a vented rotor stays pretty cool on its own. I have seen way more cracked/warped/BROKEN drilled rotors than I have solid rotors when I am at the track and THAT is extreme use....

Some also say that the slots help to reduce the glazing that can sometimes happen to the pad.

The 'boy racers' say that the D/S rotors are used in the racing world. That could not be further from the truth and they forget one thing. The racers replace the rotors every event and sometimes during a race..... They have the money to do that..... If you look at F1 series, they all use solid rotors.... even, god, I hate to say this, NASCAR. I don't like NASCAR...

I have yet to take my Zed to the track. Since it is convertible, I may never get to. If you want more info on that type of extreme use, AlanL and others who track their cars can add more info or rebut my opinions... On the track we have a 03 Vette and a 02 Miata....

Brembro make a outstanding caliper, but you do have to ask yourself, with the type of driving you do, do you really need it....

My stock BMW calipers and Axis Deluxe Ceramic pads are just outstanding.... I am always amazed at how fast the Zed can stop.... I have to watch to make sure I am stopping tooo fast. I worry about the moron behind me that can't stop that fast...but thinks he can...

If you just want the bling look, and they do look nice, go for it...

This is just information. Make up your own mind....
 
Shipkiller said:
I have to watch to make sure I am stopping tooo fast. I worry about the moron behind me that can't stop that fast...but thinks he can...
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Had that yesterday! Fortunately the SUV behind me kept a slight distance, but unfortunately for him, the car behind him did not :wink: Geez, I hate ATL drivers! :headbang:
 
Well I saw Rick Hunter’s M coupe and others and they have drilled rotors. I think AlanL has the same, I think. Why would BMW put them on the more expensive cars/faster zeds it they were not better? I do not have the technical knowledge, just subjective reasoning. I have photo after photo of comp cars with them on so that is why I was thinking they must be better. ShipKiller you know I am no racer, :driving: and 95% of the time my Zed is in the garage just looking pretty. It is just a weekend fun car for me. But I think the drilled ones look better, but would not do a mod just for looks. That is my rule, not for anyone else. But I wonder about the drilled on other Zed’s like the M. If not better why? :?
 
Just to stir the pot :stir: .

BTW, my understanding is that the newer materials, used for slotted and drilled rotors, no longer exhibit the problems you have previously seen.

There are many claims as to the benefits of drilled vs slotted rotors on stopping power. This guide is intended to provide some facts about drilled and slotted rotors. As a member of the SAE (Society of Automotive Engineers), I was pleased to see a paper "The Effect of Rotor Crossdrilling on Brake Performance" by two GM engineers published in 2006. They examined three vehicle platforms with cross-drilled rotors vs standard rotors to measure convection cooling capability, fade characteristics, wet braking, pedal feel and lining wear. The result is summarized as follows:

For the sports sedan, the coefficient of friction was 21% higher for drilled rotors than standard front rotors at 340F and higher using 15 brake snubs at 62mph. The track simulated 124 mph fade test showed 37% better brake output for drilled rotors. The drilled rotor brake temperature was about 150 degrees cooler.
For the performance car, the coefficient of friction was significantly higher for drilled rotors especially at high temperature.
Wet braking at high pedal pressure was the same for drilled or standard rotors. Wet braking is not significantly improved by drilled rotors.
Pedal force was much more consistent with drilled rotors over the brake temperature range. That is, to stop at the same deceleration rate, the driver does not need to modulate pedal pressure based on different brake temperatures. This reduces driver fatigue and improves brake response.
The authors also reported that drilled rotors prevent pad resin glazing on the rotor. So we now have solid evidence that drilled rotors have benefits over standard rotors. However, I have not found any published paper to show how slots affect brake output. So I reviewed inertial dynamometer tests using ISO NWI 26867 from Link Testing in Detroit with slotted rotors vs standard rotors. The results showed no significant difference in the coefficient of friction during the fade sections, hot stop section or pedal sensitivity portion of the test. My hypothesis is that slotted rotors do not contribute to rotor cooling whereas drilled rotors improve convection heat transfer to cool rotors and reduce brake fade. I should also point out that the pad lining wear for the slotted rotor was very severe during the test, i.e. the pad was chewed up over 20% more than the lining with stock rotors. While I believe that slots will help remove gas and debri from under the pad, I am not sure that this has a significant effect on brake torque for normal street driving. Perhaps the effect of slotted rotors is more significant on the race track, and conversely, I believe that drilled rotors are better for street and highway driving. For most drivers, I recommend drilled rotors over slotted rotors, and this conclusion is supported by the fact that Corvette, Ford GT, Porsche, Mercedes and BMW come with OEM drilled rotors.
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YMMV :thumbsup:
 
Good info.

See.... someone came up with some info that I did not have.

Can you send me that link? Time to do some more education....to myself..
 
Ovrkll - I like that bit of research. :thumbsup:

I fitted drilled Brembos to my X5 and quality pads. I can categorically state that braking is way better with them and less prone to fade. I warped 2 sets of standard rotors and these are still as new. Nope I don't race but I do tow 2 tonne Jeeps around. For sure the trailer is supposed to brake itself, but they never do fully. Bottom line is I'm 15,000-20,000 mile on crossed drilled rotors. No pad wear, better stopping, better look for sure and I'm much more confident crossing the Alps, Pyrenees and even some minor Wales passes with 4 tonne being stopped by Brembo..

I did extensive reserarch before fitting and concluded that slotted were designed to degas, shave pads and not suitable for road use, but drilled or plain were best. Key was to get the drilled holes with chamfered edges to remove any stress points


For general road use I have no research to point to but I bet absolute braking ability in a single application has far more to do with condition of the system, tyre pressure, tread depth, tyre typre, good condition shock absorbers, etc. than the pad or rotor ??
 
Well it is the consensus of opinion that putting drilled breaks on my Zed is a bad idea. I received many posts on this forum and others and several private emails most were negative about the idea. I do not track but I do like to zoom around the mountain passes here in my area of the world and the brakes do heat up very badly at times. I can not afford to convert to a big brake kit with the associated larger wheels and tires so I yield to your expertise and I will put better pads on, but forget the drilled rotors. Thanks for all those who gave me advise. :)
 
That's the beauty of boards like this where you can get lots of opinions on which to base decisions, not just sales pitches from retailers and magazine adverts. :thumbsup:
 
Does anyone have some level of documented reliable proof that drilled and/or slotted rotors are prone to failure under varying conditions? This debate reminds me of the Armourall protectant debate some years back. It did, it didn't accelerate or promote vinyl deterioration etc. Thanks.
 
On this topic, I am much willing to have my mind changed. There is just no hard data that drilled rotors are better.

I do think that on a car that is driven normally and not tracked, the longevity of the drilled rotors would be the same as solid ones..

They DO look better..
 
Yeah, I hope no one takes my question wrong...I am only asking for some type of validation to the process...some sort of irrefutable test.
 
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