RE: Carbon Brakes Set For New M5

RE: Carbon Brakes Set For New M5

Wednesday 28th September 2011

Carbon Brakes Set For New M5

F10 M5 will get optional carbon-ceramic stoppers by the end of 2012



Carbon-ceramic brakes will be an option on the latest BMW M5, and could be on sale by the end of 2012, according to BMW's Purschasing and Suppiler Network boss, Dr Herbert Diess.

That font of much knowledge of things BMW, Bimmerfile, has revealed that BMW is working on a carbon-ceramic brake package with Brembo for the M5 (and consequently also the M6). It also points out that Brembo and SGL Carbon have established a joint venture to manufacture carbon disc brakes, and that SGL Carbon already has a more general deal with BMW to develop carbon fibre for use in its passenger cars. Happy families all round, really...

Apparently, the calipers will be the same whether they're grabbing steel or carbon discs, but the larger disc diameter will mean that it will be necessary to fit 20-inch wheels to carbon-shod cars.

Author
Discussion

bern

Original Poster:

1,262 posts

219 months

Wednesday 28th September 2011
quotequote all
With their improved braking performance, isn't their a case for fitting smaller discs and therefore smaller lighter wheels?

Toffer

1,527 posts

260 months

Wednesday 28th September 2011
quotequote all
It will be a costly upgrade and even costlier to service. Think around £5K+ to replace...

EDLT

15,421 posts

205 months

Wednesday 28th September 2011
quotequote all
Given how M5s eventually depreciate, these are going to be uneconomic to service in ten-fifteen years time.

GroundEffect

13,819 posts

155 months

Wednesday 28th September 2011
quotequote all
bern said:
With their improved braking performance, isn't their a case for fitting smaller discs and therefore smaller lighter wheels?
That's not how carbon brakes help. Carbon brakes don't actually provide any higher stopping power (which is still fundamentally limited by tyre grip), they just reduce unsprung mass and are less prone to fading under heavy use.

LewisScoob

30 posts

163 months

Wednesday 28th September 2011
quotequote all
Is the theory of Carbon discs not that they last much longer than steel items?

Ozzie Osmond

21,189 posts

245 months

Wednesday 28th September 2011
quotequote all
GroundEffect said:
they just reduce unsprung mass and are less prone to fading under heavy use.
Which IMO make them a very expensive addition to a road car for very little real world benefit. The whole "big wheels 'n' brakes" scene has a lot more to do with marketing than engineering.

Carnnoisseur

531 posts

153 months

Wednesday 28th September 2011
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Interesting article, but my money would still go against a Panamera Turbo.......

thinfourth2

32,414 posts

203 months

Wednesday 28th September 2011
quotequote all
Carbon brakes and electrically operated leather armchairs


What exactly is the M5 meant for?

GroundEffect

13,819 posts

155 months

Wednesday 28th September 2011
quotequote all
doogz said:
GroundEffect said:
bern said:
With their improved braking performance, isn't their a case for fitting smaller discs and therefore smaller lighter wheels?
That's not how carbon brakes help. Carbon brakes don't actually provide any higher stopping power (which is still fundamentally limited by tyre grip), they just reduce unsprung mass and are less prone to fading under heavy use.
And since we know overall braking force is limited by tyre grip, and that large brakes are fitted to reduce heat and therefore fade, and that carbon brakes are much better at resisting/reducing both, the point stands. They shouldn't need to be as big.
Well you could extend that to the use of steel brakes - if braking effort is limited by tyre grip, why fit those massive brakes? Surely the size that is on them reflects the mechanical grip of the vehicle? Therefore switching to carbon brakes offers the same stopping power but for less weight penalty.

GroundEffect

13,819 posts

155 months

Wednesday 28th September 2011
quotequote all
doogz said:
GroundEffect said:
Well you could extend that to the use of steel brakes - if braking effort is limited by tyre grip, why fit those massive brakes? Surely the size that is on them reflects the mechanical grip of the vehicle? Therefore switching to carbon brakes offers the same stopping power but for less weight penalty.
Of course. But steel brakes aren't able to dissipate heat as well as carbon ones, which is why they are the size they are.

You could switch to carbon brakes, that would still provide more than enough braking force to lock the wheels at any point, were smaller than the steel ones, weighed less, and allowed you to fit smaller wheels too.

Although most people these days want the bling.
I have to say, I don't know a great deal about brakes (the above is about the extent of my knowledge), do you know how much of the brake size is related to the friction area/torque increase from the larger disc and how much is due to the necessity of cooling them? Do they oversize steel brakes by a significant margin?

I'm a powertrain engineer - I only care how fast I can make it go, not how to do the reverse biggrin

Blown2CV

28,697 posts

202 months

Wednesday 28th September 2011
quotequote all
LewisScoob said:
Is the theory of Carbon discs not that they last much longer than steel items?
would have thought so, steel ones only need replacing due to heat damage causing warping or fissures etc

E38Ross

34,946 posts

211 months

Wednesday 28th September 2011
quotequote all
thinfourth2 said:
Carbon brakes and electrically operated leather armchairs


What exactly is the M5 meant for?
An huge super exec saloon with big performance stats. As it has been for over 25 years.

Zod

35,295 posts

257 months

Wednesday 28th September 2011
quotequote all
thinfourth2 said:
Carbon brakes and electrically operated leather armchairs


What exactly is the M5 meant for?
All the happy people who buy it, as has been the case since the E28.

alexpa

644 posts

171 months

Wednesday 28th September 2011
quotequote all
If driven as spec intend, it needs them. I dought the standard brakes would last a track day.

Yeloperil

147 posts

206 months

Wednesday 28th September 2011
quotequote all
Carbon discs or CCM as the Brembo product is referred to are always thicker (currently anything up to 38mm) and greater in diameter than their cast iron counterparts due to their efficient thermal conductivity and therefore the ability to dissipate heat / energy much more quickly. It would therefore seem unlikely for BMW to be able to share a common caliper between CCM and cast iron.

AntJD

22 posts

153 months

Wednesday 28th September 2011
quotequote all
Dont carbon brakes need to be upto temperature before they work properly?? If so then your M5 could be deadly in the rain or on a cold winters day, seems a little too far for me. If the ideas is to make the M5 a better track day car then why not buy a propper track day car and a norman BMW??

MDahmen

6,895 posts

176 months

Wednesday 28th September 2011
quotequote all
Guess all the people in the autobahn, who cinstantly brake from high speeds for hours, will be happy.
As will the people driving on uk roads thanks to the reduction in unsprung weight and resulting improved comfort ( I assume that nearly everybody will fit 20 inch rims anyway, needed or not)

Dagnut

3,515 posts

192 months

Wednesday 28th September 2011
quotequote all
AntJD said:
Dont carbon brakes need to be upto temperature before they work properly?? If so then your M5 could be deadly in the rain or on a cold winters day, seems a little too far for me. If the ideas is to make the M5 a better track day car then why not buy a propper track day car and a norman BMW??
Exactly had this debate before about carbon brakes on an AMG S Class... absolutely pointless..

Zod

35,295 posts

257 months

Wednesday 28th September 2011
quotequote all
Dagnut said:
Exactly had this debate before about carbon brakes on an AMG S Class... absolutely pointless..
In the UK, I tend to agree. For Germans who like to drive at 150mph+ on the Autobahn, whcih entails much braking from that speed down to less than half, they will be more useful.

Julian M

12 posts

151 months

Wednesday 28th September 2011
quotequote all
But it seems everyone has forgotten, this is optional. For years I have seen on lots of sites people complying that the m brakes are not as good as they could be. This is defiantly a good step forward.