I am a car wash operator with two locations in the greater Cincinnati area, so I see a lot of different makes and models of cars, and I really like cars in general.
My question is this: why do certain models of cars generate so much more brake dust than others? I’m specifically thinking of BMW’s, Mercedes’ and Volvo’s being the prime culprits vis a vis their American or Japanese counterparts. I realize those cars tend to be higher end, more expensive vehicles that will have larger than average brakes…but I get Caddilacs, Corvettes and all manner of other cars with huge brakes that don’t generate nearly the amount of brake dust on the (mostly front) wheels.
Why is this? Is there something specific that these European car makers use in their brakes that isn’t present in other vehicles made elsewhere?
Snarky answer? Those are the people who tailgate, ride their brakes, accellerate at red lights, speed everywhere, and mash on the brakes at every opportunity.
I have had two XJ8 Jaguars, and dust is pretty heavy on all wheels. The only answer I ever got from the service adviser is that they are a special type of high performance disks and will always shed. From reviews I have read, these are indeed brakes that stop in very short distances compared with other fast and heavy cars.
As I tend to drive pretty fast (the speedometer goes up to 170 mph, but never got it up that far), as do many with a car like this, it pays off to have really good brakes. BTW, i don’t tailgate, ride the brakes or otherwise drive like a old fogey, even though I am one.
I had a Mercedes sedan a few years ago and that had the same problem. Nice car, but no comparison with the Jag. Of the 29 cars I have owned, it is by far the best.
I’m guessing it has something to do with static electricity and air flow. The pads are metallic. As the particles fly off they probably have a charge that draws them to types of wheels. In my own unscientific poll, the ‘dirty’ wheels seem to occur more on vehicles where the user is on the brakes all the time. I never get dirty wheels. My brakes are more apt to rust out then wear out.
I have noticed (working in different shops and dealerships) that European cars discs brakes usually have a large ridge on the outer circumference of the disc where the pad does not contact. This means that the disc has worn significantly. The largest ridge I have personally measure was over .150 inches thicker than the part of the disc that is normally in contact with the pad. Softer brake pads and softer brake discs make for phenomenal braking but will increase the wear of the brake components and eject more material that “economy” brakes, where the ridge I see is usually insignificant.
IME with brake pads, you can have long life, low noise, stopping performance, and low dust. Pick any three, but you can’t have all four. evidently many manufacturers choose the first three with the trade-off of more dust.
All brakes produce dust. The high performance pads the Europeans used produce a dark gray/black dust.
US and Japanese cars tend to produce a lighter (and less total amount of) dust.
The trade off is in general the brakes on a European car are way better than than the average Japanese car IME.
This matches my very limited experience. I drive a Merc and my wife drives a Nissan. She’s a much more “active” driver than I am but the Merc always has much more brake dust than the Nissan.
The Nissan has good brakes, but the couple of times I’ve had to do heavy braking in the Merc I would nearly have been thrown through the windscreen if not for my seatbelt. It really pulled up quickly.
