TTAC snark-master Frank Williams writes,
My A4s both have a really bad problem with brake dust on the front wheels. Sometimes the wheels look almost like they’re black chrome instead of alloy. I’ve seen advertisements for dust shields that fit between the brake and the wheel that are supposed to keep the wheels clean (Kleen Wheels is one brand). I’ve always been wary of these, as I feared they might impede brake cooling and could result in damage to the rotors or even brake failure. Have you or any of the readers had any experience with these? Do they really work, and are my fears of brake damage unfounded? And most importantly, do they look dorky – the automotive equivalent of a pocket protector?
Sajeev replies:
I do not recommend dust shields simply because they look dorky. Newer shields are vented and are likely to withstand the rigors of mundane driving without cooking your pads and rotors, so I can’t whine about that. But that’s just a guess.
My point: dust shields look terrible because we are conditioned to see nothing between the wheel and the brakes. Its just a matter of time (the next rainy day?) before cleaning the shields is needed to keep them invisible, and I suspect that defeats the purpose entirely.
My solution: replace your pads. I’ve noticed many German cars come with unbelievably dusty stoppers. The (small) amount of brake dust from Performance Friction pads works for me, and they have plenty of bite and almost no brake squeal. There are other aftermarket alternatives, but after one day of 130 miles of open tracking on my (daily driven) land yacht I am pretty happy with these pads in every respect.
Best and Brightest, what do you think?
Ceramic brake pad compounds seem to do the trick for me. Quiet, good braking, and low dust.
They tend to cost more, but it is worth it.
-ted
You could upgrade to the S8 – the carbon ceramic brakes not only last 150,000 miles, they generate no dust.
Would it be okay to guess that you’re probably using stock pads? That wheel looks like a B7 A4 wheel and if you’re in the US that means the stock pads are 8e0-698-151-G which are made by Ferodo (division of Federal Mogul) and have a DOT rating of FF (0.35-0.45) That isn’t a terrible material… but it does seem to produce a dust with a dark coloration. You can opt for an alternate friction material with a lighter color dust as not to make the wheels appear dirty. If you do opt for a non stock material, be sure that it has a coefficient of friction rating of FF to maintain bias and braking characteristics… unless you simply don’t care about how it drives and just want dust free brakes.
Audi has in the past suggested that dealerships wax the wheels to ease cleaning. The provided chemical was 3M performance finish 39030.
For tracking… Ferodo DS2500 and DS3000 are fantastic pads. I run them in my custom brake setup with great results. I also use Porterfields too. The real solution is to learn to love matte black wheels which don’t require cleaning till they are obviously turning a brownish color from the pad dust.
Also…
Adding shields to keep dust in… not smart. If your rotors are as I suspect them to be 8E0-615-301-AD, they’re wheel side vented. So you will likely elevate brake operating temps by adding those brake covers. Higher temps can expedite pad wear and rotor wear or if you are tracking and have enough power… warp, cause pad deposits or do other fun things to your front brakes.
One of the places I buy stuff from has a FAQ that is sometimes a good read. http://raceshopper.com/tech.shtml
I hate brake dust! But add on covers? eeew.
As part of the LTZ package my Impala has the
18″ five spoke aluminum wheels. So far I’ve used
mild car wash soap and elbow grease,and they don’t look bad.
I have noticed less brake dust acumulates on
the Impala than than my old Grand AM. I can have the wheels spotless on my Firebird,and a couple of
trips around town,and there dusty. Whats that all
about?
More questions.Why do some aluminum wheels oxidize? Is it wheel weights? Or harsh detergents?
We have a Jimmy for a winter vehicle,and I have given up on the wheels. Six years old mostly winter driven and the wheels look like crap?
Brake dust is like honest dirt on your clothes. It shows you’re doing your job, so why worry?
replace your pads. I’ve noticed many German cars come with unbelievably dusty stoppers.
Of course, there’s this. I don’t know why German cars do this, any more than I know why every Chrysler I see seems to creak when it comes to a stop.
More questions.Why do some aluminum wheels oxidize? Is it wheel weights? Or harsh detergents?
Aluminum always oxydizes, just like iron (except that it’ll stop once the top layer of oxide forms) unless you make it into a stable alloy. What’s happening is that the alloy the rims are made of isn’t chemically stable, or they have a weak coating.
Definitely change your pads, and use P21s to make cleaning your wheels easier.
I also wouldn’t use those dust shields. As others have said, they are ugly and compromise brake cooling. Cleaning the wheels often seems to be the only real solution. Some brake pad formulations make more and/or darker dust than others. Premium grade ceramic pad formulations such as Akebono’s Euro do seem to help.
I’ve noticed the same thing on my Mazda6. It seems to produce quite a bit more brake dust than my wife’s Mustang, both of which it is my husbandly duty to wash. Thanks to the B&B, I guess I’ll look into ceramic pads when the time comes. Of course, if they really do last 150,000 miles, as JMO states, they’ll proabbly outlast the car (coming up on 60k on the original pads with plenty of life remaining).
Oh yeah, and I would never use the dust shields. the dorkiness/ugliness is a nonstarter even before considering the effects they might have on my brakes. I picked the style of rims on my Mazda6 because I like the way they look (and they were cheaper than replacing 2 bent OEM rims), and I’m not about to do anything to ruin that look.
Change pads – as per above recommendations.
Brake dust shields are so…1984 (that’s when I last had them on a car…a BMW 325e).
On my Mazda Tribute, replacing the stock pads with a ceramic pad has done wonders to reduce dust. It also quit eating the rotor as badly (which was the other part of the dust contribution equation.) On the Subaru WRX, I have had a few different pads and have become the most fond of Hawk HPS for a basic street pad.
Brake dust is a no-cost option that comes with all German cars.
Twotone
I have hawk hps on my wheels & it seems better than the stock sti pads (cheaper as well…)
+1 on the ceramic pad recommendations. My wife’s Chrysler Town & Country used to deposit an incredible amount of black brake dust on its alloy wheels. Changing to Akebono ceramic pads and installing new rotors cured the dust problem. Brake feel and performance are also much better than they were before the brake job.
Brake dust is like honest dirt on your clothes. It shows you’re doing your job, so why worry?
Brake dust is bad for the wheels, and it’s harmful to the paint. It does need to be cleaned off, and German cars tend to generate more than the norm. (If I’m not mistaken, there is more carbon in the brake pads than the norm, hence the dust.)
I agree that changing pads is the best answer. You might also want to wax the wheels, although in practice, doing that on wheels such as yours is a PITA.
Clean the wheels often. When washing the car, start with the wheels, so that you remove whatever dust that ends up landing on the paint as soon as possible. And do avoid washing the rest of the car with whatever soap/water mixture or cleaning mitts that you may have used to wash the wheels.
My mom had 3 Audis over the past 12 or so years, and every time she picked up a new one, I would get her a set of the Kleen Wheels. I am not as against them as Sajeev seems to be.
That said I would never put them on my own car. I do believe they impede brake cooling, and if you like to wash your car once in a while they get in the way if you want to clean your wheels.
But for mom, who drives easy all the time, doesn’t wash her car near as often and takes it to the local place where they wash it for you, the Kleen Wheels are a fine defense against that grimy german brake dust. One experience with an old Audi 80 with the zillion spoke BBS wheels was enough to convince her.
Couple of points for install. Clean the wheels really well off the car first, and when you install them, line them up carefully with the bolt holes and push them in once. If you have to take them out to realign, the edges tend to pull up a little where you had to pry the disc out, and then you have created a little “vent” that will let wisps of dust down the road.
And counterpoint to Sajeev: You reccommend different, less dusty pads which is great, but it is at least somewhat true that those dusty pads the germans use provide better brake performance. Everything in engineering is a compromise and you’d be hard pressed to think that the smart alecs in Ingolstadt are using those pads just to spite their customers. Just ask Porsche why they use dusty pads. Or read the C&D braking article from a couple years back, they proved a Passat with the its dusty pads easily outbraked American and Japanese sedans when things got a little toasty. You could make the argument that we don’t need good 100-0 performance in the US of A though, GM and Honda certainly feel the same way.
Definitely change the pads, not shields. I have Hawk HPS myself and they have a bit of dust, but less than many brands. They stop extremely well however (which is more important to me).
How are ceramic pads for stopping? are they much better than standard? I don’t have a dust problem, what with my steel wheels and plastic hubcaps (I did on my old Saturn), and the Accord certainly does a good job of stopping, but I am always interested in improvement, especially where safety is concerned.
I have crazy brake dust on the front wheels of my Mazdaspeed6. To complicate matters, the stock rims are a 15 spoke design. Cleaning the rims on the car is quite a hassle. I have found that using teflon wheel cleaner once a month or so makes it so that the dust will spray right off in most automatic washes or with a high pressure do it yourself wash.
Power6 : And counterpoint to Sajeev: You reccommend different, less dusty pads which is great, but it is at least somewhat true that those dusty pads the germans use provide better brake performance?
Not really, we are talking about generalities. To that point, you’re forgetting that German carmakers are still in it for the money. Their pads are engineered to a price, and something must suffer. In this case, its stupid amounts of dust.
Aftermarket pads aren’t bound by their parameters, whatever they are. I’ve seen the benefits of switching over to performance pads from the aftermarket and haven’t looked back.
Many others posting on the blog seem to agree.
You can learn to love dusty wheels (I have, upto a point)
Try switching pad material, your mileage may vary though. I found the Hawk HPS pads that many folks are recommending made loads of murky brown dust on my WRX. Slotted rotors may not have helped. Axxis Ultimates were much better from a dusting perspective. Both offer excellent braking, though the HPS pads were a liitle reluctant to stop for the first time on really cold mornings.
Waxing your wheels helps a little bit, but not much (I actually waxed half of my wheels with Rejex once to test this, perhaps another ‘wax’ would be better – Zaino perhaps).
If you swap rims, you could try going for some dark ones. The gunmetal Rota Attacks I use on my WRX in the summer can hide a lot of filth.
I would only amplify both the positive feedback on the Hawk HPS Pads AND the fact that on cold New England mornings they require one stop to warm-up and quiet down.
Not really, we are talking about generalities. To that point, you’re forgetting that German carmakers are still in it for the money. Their pads are engineered to a price, and something must suffer. In this case, its stupid amounts of dust.
True, that is a good point. Yes money is one of the things that can overcome the tradeoffs of cheap OEM pads, and I did overlook that.
I think it still depends who you are. I still wouldn’t reccomend it to my mom because she wouldn’t see the value in a new set of pads and the labor she would have to pay for if I can’t get there to do it myself. Plus, as you probably know from almost any performance pad, there is a tradeoff in the first couple dead-cold stops each day that is probably better left to those who know what is happening down there.
Changing pads is something I would certainly do, and is probably the better idea, and appropriate for everyone in this audience, so I retract my former sentiments.
To that end I would reccommend Porterfield R4-S, not too much dust, and they work well from bitter cold to track days. Just make sure they don’t put the race version R4 in the R4-S box, like they have done to me twice!
Coincidentally —
The New York Times
July 6, 2009
Brake Dust: A Problem That’s Not Really a Problem
I saw the ultimate solution to brake dust this weekend. A dark grey powdercoat.
@ Andy D,
What? The whole car!!!!! ;-}
Power6 : “there is a tradeoff in the first couple dead-cold stops each day that is probably better left to those who know what is happening down there.”
Friction materials are tricky and the combination and proportions of materials used in a pad will play into how much friction a pad offers at different temperatures.
If you look at the temperature/coefficient graphs available for pad materials you’ll see some pads offer drastically less friction when cold. You might have a pad that offers 0.30 coefficient when at say 100*F but 0.40 at 400*F. That is a 33% increase in friction for the same pedal pressure. You’re going to notice that. SO an EF DOT rating pad might not be so great if you like cold stops but don’t have huge diameter rotors to afford leverage, or huge diameter caliper pistons to afford massive clamping force which can balance out the low coefficient pad material.
Not all performance pads are horrible when cold, EBC yellows circa 2005 were scary and dangerous when cold… they’re also a meh pad. Ferodo DS3000 are actually streetable but they are loud and probably eat rotors… but they don’t seem to give that non-retarding sensation of a cold track pad. Yes those are both track only pads but it illustrates the point that not all performance pads have to be crap when cold.
I too use the Porterfield R4-S and they worked great in balance but I selected the R4-S due to it’s coefficient at temperature and the temperature range offered by the pad.
I figure I should also mention…
Some pad mfg’s will provide info on pads, others will only suggest pads for you. Having done some brake system calculations and tinkering with custom brake systems I lean towards being provided technical info prior to consideration for purchase.
Some pads are a particular formulation regardless of the pad shape. As in a Ferodo DS3000 for a 996 is the same material as it is for a Honda Civic Si. The pad formulation on OE pads is usually listed on the backing plate, the DOT may require this. Aftermarket pads aren’t always so transparent when it comes to formulation. An aftermarket pad from brand X named Pad Y may not be the same exact material formulation for demonstrate the same coefficient of friction as pad Y for a different caliper. I’ve seen this as evidenced by different DOT pad ratings on the same brand/product pad material for different caliper designs.
If you take the effort of washing the car once a week and using the right soap, there is no problem with dusty rims.
A lot of commenters want to change the pads for pads that produce less dust. OK. But it seems that we have here a lot of people knowing more about brakes than the Audi engineers.
Changing the pads for another type, changes the braking performance. Sometimes for the better, but in most cases for the worst.
And if you are on a twisty mountain road, going downwards and your brakes give up, only because you wanted less dust, are you still that happy?
I have stainless steel wire wheels on my old Jaguar. You have no idea how painful life can be until you have to clean wire wheels. I switched to ceramic brake pads and while still dusty, they are so much less dusty than before.
–chuck
Power6 : I think it still depends who you are. I still wouldn’t reccomend it to my mom because she wouldn’t see the value in a new set of pads and the labor she would have to pay for if I can’t get there to do it myself. Plus, as you probably know from almost any performance pad, there is a tradeoff in the first couple dead-cold stops each day that is probably better left to those who know what is happening down there.
I’ve noticed that cold behavior, but then it went away when I switched to the PF’s more costly brake pad model. (which name currently escapes me). Then again, it really doesn’t get very cold in Houston, so this is FWIW.
If you don’t do your own brake jobs (come on, its stupid easy these days) I can see why spending $$$ on shields is a good idea. And for most people on flat roads, they aren’t gonna feel a difference.
————
albert : Sometimes for the better, but in most cases for the worst. And if you are on a twisty mountain road, going downwards and your brakes give up, only because you wanted less dust, are you still that happy?
Its one thing to have faith in OEM engineering, its another to think they put the absolute best stuff on their products.
Luckily I am not the only person saying this, but you can use other brands of pads for the same stop, with less dust.
I can’t think of one instance in the numerous cars I’ve owned over the years where aftermarket pads were not an improvement in overall of braking performance over factory pads, including reduced brake dust where that was an issue (and it is with me, too).
I recently changed the stock pads out of my 1996 Porsche 993 for a set of Porterfield R4S pads. Like them a lot, used to use them on my old Carrera 3.2 – low dust, better modulation, really bite well, no fade, great compromise between street and track performance, and according to my Porsche mechanic who also races, they’re better on rotor wear than the factory OEM pads.
The caveat is to do a little homework first. There are plenty of on-line forums and web sites relating to specific marques that can be a great source of “on the ground” information from current and former owners. Brake pads are usually a well-discussed topic on the sites, so you should be able to glean quite a bite of insight from forum members’ comments on what pads work vs. what don’t for specific applications.
As a general rule of thumb, though, for a street-driven car, even one that is occasionally tracked or autocrossed, stay away from high-friction coefficient pure “race” pads. There are plenty of good high-performance street pad options (like the Porterfields) that produce low dust and improve braking performance over stock pads, while being kind to rotor wear.
Bottom line: Do some research up front, decide which pad will likely work best for your needs, then just do it. It’s a relatively simple and inexpensive (in most cases) mod that usually pays real braking performance dividends.
The decision on covers would really come down to driving style. If this is your hyper-miling commuter, go for it. If you are Baruthing your way across town every day, forget it. (You knew it was only a matter of time, Jack.)
I’ll also weigh in for ceramics. I have EBC Red Stuff (love ’em) on my old tank. The first stop in really cold weather is a few feet longer, but after that they might as well be arrestor cables.
(My wife’s car is a Ford, so we don’t discuss those brakes.)
Brake dust is bad for the wheels, and it’s harmful to the paint.
Is it? I was under the impression that it wasn’t any worse than normal street dirt, and certainly far less nasty than road salt.
I usually only cleaned and re-protected my wheels (and the whole body) before and during winter to mitigate salt damage. They seemed to do fine.
Ceramic pads did the trick for me while not taking much away from the performance. I have an Infiniti G35 Coupe that had wheels turning black by going around the corner. I went for the Akebono Pro Acts. Cheap, almost no dust, no squealing and easy on the rotors.
Brake dust is proportional to amount of friction the pad generates.
If you want to loose your fillings when you step on the binders, then you will pay the price with black,ugly dust.
I have found pads which were listed as “Semi-metallic” to be lower in dust than OEM, however the first brake application in the cool morning will open your eyes faster than a double expresso as you slide past your intended stopping point.
There are two detailing products that come to mind that are NOT “wheel wax” which IMO is useless.
One, from Michelin (the tire maker,)is an colorless effervescing spray which seems to work by establishing an anti-static state on your wheel surface- the dust is just ‘repelled’. The other from Eagle 1, is also a clear spray, but this seems to deposit a clear shield coat on the wheel. The Eagle 1 product has a side benefit in that it makes the wheels shine like you spent hours buffing them out. Both products seem to emit enough VOC’s to anesthetize a cow-so do like Bill Clinton did.
The only problem; you will be a slave to every rain storm, or puddle you drive through, as brake dust and water make a deposit similar to fine black cement regardless of your application.
Other than that, both of those products work well enough to keep your wheels clean for at least 10-14 days of everyday driving.
Regards,
BD
Friction materials are tricky…
qfrog…Thanks for the info, I think I followed most of it! Obviously you understand brake pads on a whole other level, in much more depth.
All that aside, can you tell me, other than experience, are there any specs I could be asking for when buying high-perf pads that would help me buy the right thing on the future? Would a mfr. willingly provide anything of use?
I ask because in the future I might want to say…swap 12.4″ Legacy GT rotors and calipers for the 11.x” stock setup on my WRX. The rear brakes are just about the same size and spec on both cars, and I can easily figure out the piston area and therefore leverage difference, but I don’t know how to figure out what sort of pad would make sense if the clamping force is higher, or how to quantify that. There is plenty of talk about whether a brake swap like this “throws off brake balance” on either side, but no talk of how the math works out for any of that…
there are tons and tons of low dust options out there
just remember – everything is a tradeoff
noise
performance
dust
you can’t have it all.
Power6 :
Very welcome… I’m just starting to understand brakes. There is an incredible depth to this topic. This level of understanding has taken me the better part of a year to attain. A brake system engineer will be able to school me something awful. However that won’t stop me from rambling a bit… maybe Fargo will delete due to length but I’ll post it anyways. Hi Robert!
I agree that everything is a tradeoff… and some pads cost a whole lot more than others.
This is a Subaru worksheet I found… the guy who built it was probably a bit more geek than I am… respect the effort he put forth. http://files.getdropbox.com/u/913220/brakemath.xls
When working with a particular vehicle I usually assemble a vehicle specific brake system bias calculator (a generic one I like http://pws.prserv.net/usinet.Young/BrakeBiasCalculator.html) using excel and do some analysis of the stock system. Once I know the stock bias I can target that and plug in front and rear pad coefficients as values… this allows me to get close to the stock bias but gain temperature range or reduce pedal effort or whatever the objective was. This sort of calculator becomes more useful when comparing the torque production of say a four or six piston caliper with a larger rotor… and how those components will work with the existing rear brakes. With a calculator you can determine how much more coefficient is needed in a rear pad to keep the car biased correctly once a big front brake kit has been installed. Granted this is somewhat academic and theoretical, some trial is necessary to validate the calculated numbers. I have however had good results geeking out and using this technique.
IMO the smart way to approach brake upgrades is to decide WHAT is wrong with the brakes. It is possible to upgrade one aspect of a car’s brakes but hinder another. So you may gain repeatability but also gain stopping distance. I think that stock brake systems are often optimized for short stopping distances rather than stamina (repeated stops ad nauseum).
A WRX is probably going to have a reasonably well optimized system from the factory as it is a sporty car. The stock bias should be good for general use. That is to say… if the car is balanced and controllable under heavy braking with the stock brakes then why screw with the bias unless you have made other changes to the car the folks at FHI probably have the biasing optimized. If you need more temperature range then seeking a pad with a higher temp range but similar to stock torque production front & rear is a good move. You may also need to start thinking about brake cooling or directionally vaned rotors which are much like your turbocharger, a radial flow turbine… centrifugal flow etc.
What sort of tinkering and pad coefficients you use should be based on what sort of hydraulic brake circuit you have. If you’re dual diagonal… it is easier than if you are longitudinally split and have a rising rate type master cylinder for brake proportioning. Nissan and Subaru did this… your pressure bias is dynamic not static… makes pad selection a bit harder as you kinda have to know what pressure you will be achieving during what rate of deceleration. Again… I’m just starting to understand these things. I’ve only worked with half a dozen cars to date and most are Audi models with the dual diagonal brake circuits.
Hope this helps.
@Bocatrip:
full agreement on the Akebono Pro Act Ceramics
maybe not as good as Maker’s Mark, but a fine Kentucky product nonetheless.
indi500fan : Akebono makes pads for Audi too, not sure if it is the same compound as the Pro Act Ceramic pads tho, could be a custom order formulation.
Power6: I replied… it was long… with links. GAH filtered or something. I emailed Farago about it.
Assuming the wheels are clear-coated, I would use any old car wax on them. It makes then easy to clean.
One word of advice, do not use a water hose on the front wheels when the brake rotors are hot.
This is a geat topic.
I have often wondered why EVERY time I get out of the car wash with my Sti that I have to put my foot through the floor to break even at parking lot speeds
This may have to do with being too cold? I know not to hit hot breaks with cold water. This is called thermal shock. These breaks must have a huge penalty for being wet and cold.
This always applys to the first stop then the bremco’s work like a charm.
As for the dust when I bought my Subaru new it was really bad. IMO more breaking=more break dust. I prefer using gears.
Cheers
A lot of commenters want to change the pads for pads that produce less dust. OK. But it seems that we have here a lot of people knowing more about brakes than the Audi engineers.
Changing the pads for another type, changes the braking performance. Sometimes for the better, but in most cases for the worst.
And if you are on a twisty mountain road, going downwards and your brakes give up, only because you wanted less dust, are you still that happy?
Wrong assumptions. IMHO, OEM consumables (i.e., tires, brake pads, shocks, etc) are usually pure garbage that the automaker in question has attempted to procure as cheaply as possible. The stock pads and rotors on my 06 Honda Accord fade like crazy, give shitty pedal feel, etc. Switching to Akebono ProACT pads with Baer rotors shortened stopping distances dramatically and stopped the fade.
I’m not sure which year/model of A4, but Akebono makes ceramic pads and I’ve had good luck with Hawk HP Street pads in the past. Those won’t be quite as dust free as the ceramics (still MUCH better than stock German car pads), but they’ll have better stopping power. Do NOT use brake dust shields. Try the new pads on the front first since those typically generate the most dust. Don’t forget to put anti-squeal compound on the back of the pads if you do it yourself.
On a related note, don’t forget to change your brake fluid. A good bleeder makes doing annual brake and clutch fluid changes very easy, reduces fade, and prolongs the lives of both systems.
OE Honda pads have been horrible, but they hardly dust at all. JD Power Performance must be more important to Honda than braking performance. I use Axxis Ultimate ceramic pads on my ’06 Civic Si, and will be upgrading the pads of my Fit soon. The Si stops dramatically better, especially in rain. The OE pads on my ’04 Accord were annoyingly bad, leaving an uneven layer of crud deposited on the rotors after a year…but very little dust! Aftermarket pads made everything better, and knowing I could stop made cleaning the wheels a satisfying experience.