M66M

What's the story on the rinky-dink rear brake calipers on the new AMG vehicles? Including the s model red calipers and the carbon ceramics.

skim7x

From what I understand about vehicle dynamics, rear brakes aren't really for big stopping power... Rather, they are more to stabilize the vehicle under hard braking... So they don't get to be big beefy calipers / brakes. You need the meat up front which takes the most weight under hard braking.

KJ

The brakes are designed for maximum balance under braking, not for looks.

M66M

I can't shake the feeling that Benz is just cheaping out and everyone is lying to themselves. I'd love to hear some veteran Benz and AMG owners weigh in.

I can tell you what I think after owning 4 Benz vehicles. They are cheaping out and their build quality/designs/methods, becoming increasingly Japanese. Uncharacteristic of the German car feel that most purists, like myself, enjoy.

I also think it's a cop out to say esthetics don't matter on an AMG car. Even if the function over form statement is true, I still need to see a proper brake caliper on the back of my AMG vehicle.

Unrelated thought but they're also cheapening the AMG brand by offering new entry level models.

Following suit with the worst offender BMW, who slaps ten thousand M badges all over non-M vehicles when you order the right package. Makes it rubbish for the real M owners. I see Benz clearly going down that road. Concerns me.

GordonGEICO

What year is your W205 C63/C63S?

Periokid

Most certainly a cost savings decision. They are single piston calipers, the next step down is drum brakes.

SuckaGDog

I do feel it is a costing saving decision as well. BMW for the first time ever put on fixed piston calipers on the front of their M cars beginning with the F10 M5. Although, they left the rears with floating calipers. Everyone roasted on that car so bad because of it.

That's why I liked AMG, but I do see them following the same trend now.

GBlansten

When C&D tested the C63S it braked from 70-0 in 151 feet. The lighter M4 did that in 150 feet. So, it seems like the C63S is very competitive for its segment.

https://www.caranddriver.com/reviews...pe-test-review

ItalianJoe1

The caliper is chosen to be as light as possible while still meeting the performance needs.

If they stick a big 4-piston caliper back there, you will feel better, but you will get no difference in actual function, but it will be heavier and add unnecessary cost and complexity for no positive effects.

Accidental L8 apex

Trying to remember the racing series the "true AMG", a CLS63, raced in... you know, having those huge rear calipers and all.

GordonGEICO

Anyone care to add some technical information to this thread? IE, the differences between a single-piston floating system versus a 4- or 6-piston fixed system? I'll be the first to admit that I don't know much on the subject, and while I (or anyone) could Google the information, if someone had some specific info on AMG braking systems, it might shed some light on why the specific decisions were made, or just be interesting.

I personally don't have any problem from a performance or aesthetic viewpoint. I recognize that the rear brakes do a significantly less percentage of overall system braking, so it makes sense to me when the rotors, calipers, and such are lower-spec than the front. I was a little surprised when I noticed that the C63 had a single-piston rear caliper, but then again, I don't actually know how that affects performance versus, say, a 4-piston setup. I also noticed that even the AMG GT-R has a similar setup and that car doesn't really lack for performance in any way.

msd3075

The theory behind more pistons being better is not necessarily that you increase braking force but that your more evenly distribute the braking force across the pads and ultimately across the brake rotor (discs).

The theory behind the performance difference between fixed and floating calipers is a bit more complex.

In a fixed caliper design, you have piston(s) on each side of the caliper (both on the inside and on the outside of the rotor). Each set of pistons squeeze again a pad on that corresponding side of the rotor and (theoretically) evenly apply pressure to each pad. Only the pistons and pads move; the rest of the caliper stays fixed (hence the "fixed" name)

With a floating caliper design, you only have pistons on one side of the caliper. When it applies force to the brake pad on the piston side, that portion of the caliper with the pistons "floats" and causes the pad on the other side of the caliper to move along with it.

It's hard to explain without seeing, so look at this YouTube video for a good visualization.


Notice how both pads don't apply even pressure at the same time? This is the performance advantage a fixed piston setup has since it (theoretically) applies both pads evenly at the same time.

And when I say performance, I don't just mean stopping distance. This applies to initial bite, how linear (or non-linear) the brakes function, how the pedal ultimately feels, and so forth.

tscales

The rears on my E55 are much smaller than the front.

And let me tell you the build quality is light years better on the 2017 than the 2005. The Chrysler years were ugly.