Last week I brought my car in to be reflashed and to have the brakes inspected because they have started to shudder. When the Service Manager came out he told me that he had good news and bad news but I'll get to that in a minute.

Have you ever wondered why your front brakes are always so clean and shiny? It appears that the OEM pads are too aggressive and are actually more durable than the rotors. So the majority of brake dust on your front wheels is from rotor wear!

The Service Manager said that the rotors were worn beyond spec and need to be replaced but ironically the pads are fine. They didn't have any parts in stock so I'll have to bring the car back to have the pads and rotors replaced. The rotors are being covered under warranty. The pads are not because they are not worn out and they will cost me $96. For that price I think I would rather go with an aftermarket pad that is a little more rotor friendly like the Carbotech Bobcat.

 

I've heard very good things about EBC Green Stuff pads. Check those out too.

 

Were your brakes making any noise?

 

Yeah, I was thinking about EBC and Hawk too but it doesn't look like they have pads available for the RX-8 just yet.

So I'll go with what I can order today.

 

No, not any more than normal. The brakes have have always squealed a little bit from all of the dust. Also the pads are not worn down to the wear indicator which emits a loud squeal when braking.

This is just a case where Mazda choose a very aggressive brake compound that is not rotor friendly.

 

When it comes to brake wear, there is no free lunch. According to a buddy of mine who designs friction materials for the automotive industry (friction materials=brake pads) brake dust is virtually always comprised of worn rotor materials. That is normal. If you wan't to minimize brake dust, the only way to do that is with less aggressive brake pads. Unfortunately, less aggressive pads mean longer stopping distances. High friction materials also tend to squeal more than low friction pads. Most American cars have soft, low friction pads, as Americans bitch and moan about squeal and dust. European cars almost always have the same pad material in the US as they use in Europe, which is a high friction material. Europeans have no problems with dust or squeal. Due to the higher speeds traveled in Europe, brake performance takes precedence.

 

Yes, I fully understand that there is no such thing as a perfect brake pad. My original comment was that Mazda choose a pad that was, in my opinion, too aggressive for street use. Having to replace the rotors at 17k miles seems a little early to me.

With that in mind, I would rather purchase two sets of pads to optimize the brakes for my use. The first being a lower friction pad (i.e. Carbotech Bobcat, EBC Green Stuff, etc...) which dusts less, is rotor friendly and is more suitable for daily use. The second set would only be used on track days and would be chosen accordingly (i.e. Carbotech XP8, EBC Red Stuff, etc...). These pads provide exceptional stopping power, great initial bite and are very fade resistant but they would trash the rotors in short order if you used them everyday. Plus the first couple of stops would be scary because they don't work well when they are cold.

 

I experienced this on my VW Passat and several friends with BMW's have the same experience RE: European brakes. I'm told (by VW...and they were told by BMW) that European cars have brakes that are designed for sacrifical rotors..thats how they get the stop on a dime performance. The cost is when you need to do brakes, you do all the parts. Ran us all about $500 (+/- $50)for the front axle. Rears in my case weren't so bad, had them changed early and was able to turn the rotors.

The big surprise (for me) was that the rotors were only $70 ea for the front...the pads were $137!

AT

 

Sacrifical rotors : utter bollocks IMO. I changed all 4 original rotors at 210.000 km in my previous Audi A4.

 

Atacdad,

I'm curious, how many miles did you get out of your brakes on your Passat before they needed to be replaced?

 

Good thread, guys! Interesting stuff! Glad to hear Mazda replaced the rotors under warranty...

 

Right around 45K miles. Had the rears done later at 48K (I drive almost exactly 1000 miles/month for work). My shop (did not have dealer do them) said the rears had plenty of pad left, and that I could get another 5K miles, but I had them done anyway.

AT

 

On the RX-8? Mine dust terribly - the front wheels will be getting dark less than a week after washing.

But, I gotta disagree with your conclusion, to my knowledge brake dust is from pads, not rotors - and European cars, especially German cars, are notorious for having serious brake dust problems. (I have an Audi allroad, and you just need to look at any Mercedes, BMW, or Audi front wheels to see it.)

Regards,
Gordon

 

For what its worth, the EBC Green Pads are the dirtiest pads in terms of brake dust, I have ever had. They are installed on two of our Company vehicles - a Ford Explorer and a Pontiac Montana van and both have FILTHY front rims virtually all of the time since the install.

Both drivers are very satisfied with the performance of the pads, however.

 

Gordon,

I think that you may have misread my comment. My front brake rotors always look bright and shiny (can't say the same for the rear). While my front wheels are normally black with brake dust after a week's worth of driving.

With that observation I came to the conclusion that the dust must be metal particles from the rotor for two reasons. First the rotors are worn to the point where they are no longer in tolerance. Second, the pads are hardly worn. So one could logically assume that the dust is coming from the item that is wearing the most which is the rotors.

 

Also.....

an observation that supports the aggresive pad comment;

Have you ever noticed how quickly minor grooves on the rotors come and go? Yes, I realize that some grooving on rotors is normal, but with the RX8...they wear away very quickly.

I have noticed on my last car (VERY little brake dust) that grooves appeared slowly and dissapeared slowly. Over a month or two the surface of the rotor would change. All perfecty normal behavior for any car as the pads and rotors wear together.

With the RX8 however, its the same thing BUT, much faster. One day I'll notice a minor groove...the next day...no trace of it. another will appear....gone in a day or two. What does this say to me? Our rotors are wearing very fast. What takes a month on another car (2000 Solara) will take just days with our brakes.

The RX8 brake pads are fairly aggresive for a street pad.....after all they have all the traits. Can be noisy, excessive dust, and chewing up the rotors. I think the only difference between RX8 stock and track pads are that our stock pads have a lower operating heat range.

I wonder if we can send a dust sample to the Blackstone company for analysis. You know.....some guys sent their oil there.

This will tell you what it is for sure. I'll also bet there is a cheaper way. Seeing that the rotors are cast iron, maybe if a large enough sample is collected...it will be attracted to a magnet. Any thoughts?

 

Has anyone who has had to replace front rotors gone with a different non-mazda rotor? Any feedback on this option?

 

I wore out WRX rotors and pads in 12K miles, so I'm not surprised that someone wore out the '8 brakes in 17k.

The '8 stops hard.. gotta pay a price for that somewhere.

 

Speed Racer,

I know your rotors will be covered under warranty, but do you know what they cost each?

My guess is when it becomes common place that the RX8 rotor pad combo is hard on rotors....it will soon be considered a wearable item that is not defective. Once you have over 20K on the ODO....and dealers realize its just how the RX8 brakes are....it will be harder to get them to replace rotors for free.

They wont do the pads now....its only a matter of time before they wont be doing the rotors for free either.

You have 17K....I'd say thats more than most RX8's on the road....lets see how our brakes are with that milage......I bet they will be not much better, and by that time Mazda may not be giving out free rotors...

 

The service manager didn't mention the cost of the rotors. The next time I talk to him I'll ask about the rotors.

This morning I called Carbotech, Hawk, and EBC to inquire about brake pads. At this point Carbotech is the only outfit that is even tooled up to make them. So I ordered a set of Bobcats for daily driving and I'll have to wait about a week before they will have a chance to make them. The only thing that they had in stock were the XP8/XP9 all out race pads. So I picked up a set of those too so that I'll have something appropriate for track days.

I think that I'm going to be scared to see my Visa bill this month (bought JIC coil overs and 2 sets of brake pads).

 

Since mine's due for a wash I have a ready supply of dust. I brushed a small amount into a glass bowl and brought a magnet near it. This was a magnet from an old disk drive (strong).

All of the loose dust leapt to the magnet from about 1/4 inch away.

If you're really interested in rate of wear, your best bet would be to do regular measurement of the rotor with calipers. You should be able to establish a trend and use the minimum service specs to predict remaining life.

 

I thought the price to pay was just bigger (and therefore more expensive) rotors and pads for increase friction surface. Don't see why they should be less durable (assuming sensible driving habits of course).

IKN

 

performance car = higher running costs + consumables replaced more often.

As Psylence sais, you can trash the brakes quick if you use them hard, realy depends on your driving style.

I'd expect about 1/3rd of the pad to be done on a track day. Rotors are consumables too - and as a performance car the 8 should use parts for best performance, not longevity.

Just be thankfull were not replacing Enzo brakes every other week..

 

Yeah! Those enzo brakes are as expensive as a complete RX8 if you need the rotors AND pads.
Can you imagine burning off an RX8 in a weekend?

No mistaking it, I use the brakes on my cars hard. I'm enjoying the rx8 brakes quite a bit (except for the noise) as part of the fun is being able to scare your passengers

 

Now you just need to test the brake pad itself with the magnet to eliminate them as the source for the dust!

Seriously - I could well be wrong about the dust being mostly from the pads. The posts about the grooves on the discs changing quickly sounds like it's possible the pads are aggressive.

Regards,
Gordon