C63 PP & 507 same brakes?
05-14-2014, 09:49 PM
#6
MBWorld Fanatic!
"High deceleration, precise pedal feel, perfect resistance to fading and superior safety reserves – the AMG high-performance braking system on the Roadster offers all these features. With SLS AMG GT Final Edition specific red-painted brake calipers, the brake discs measuring 390 x 36 millimeters (front) and 360 x 26 millimeters (rear) provide the ultimate in deceleration. At the front axle, this super sports car uses brake discs featuring composite technology that has been tried and tested in motor racing. This sophisticated technology, based on a floating radial and axial mount between the grey cast iron discs and aluminum bowls using stainless-steel composite elements, provides superb heat dissipation along with optimum fade resistance, even in the harsh environment of circuit operation.
The use of aluminum also reduces weight, which has clear benefits particularly with the brakes in terms of agility and suspension response, thanks to the substantial reduction in unsprung masses. Six-piston fixed calipers at the front and four-piston fixed calipers at the rear permit generous brake lining surfaces of 2 x 120 cm and 2 x 58 cm respectively. The AMG high-performance braking system generates braking power of 816 kW/1109 hp under full braking power from 250 km/h to zero."
Not to mention my 2012 P31 C63 has 2 piece rotors stock.
Last edited by VaclavSV; 05-14-2014 at 09:54 PM.
05-14-2014, 09:56 PM
#7
MBWorld Fanatic!
You sir are very wrong. "High deceleration, precise pedal feel, perfect resistance to fading and superior safety reserves – the AMG high-performance braking system on the Roadster offers all these features. With SLS AMG GT Final Edition specific red-painted brake calipers, the brake discs measuring 390 x 36 millimeters (front) and 360 x 26 millimeters (rear) provide the ultimate in deceleration. At the front axle, this super sports car uses brake discs featuring composite technology that has been tried and tested in motor racing. This sophisticated technology, based on a floating radial and axial mount between the grey cast iron discs and aluminum bowls using stainless-steel composite elements, provides superb heat dissipation along with optimum fade resistance, even in the harsh environment of circuit operation. The use of aluminum also reduces weight, which has clear benefits particularly with the brakes in terms of agility and suspension response, thanks to the substantial reduction in unsprung masses. Six-piston fixed calipers at the front and four-piston fixed calipers at the rear permit generous brake lining surfaces of 2 x 120 cm and 2 x 58 cm respectively. The AMG high-performance braking system generates braking power of 816 kW/1109 hp under full braking power from 250 km/h to zero." Not to mention my 2012 P31 C63 has 2 piece rotors stock.
Trending Topics
05-14-2014, 09:58 PM
#8
MBWorld Fanatic!
Actually i think hes correct. Only p30 cars have true 2 piece rotors (like the girodisc one u have on order) p31, and 507 have "1.5" piece. If u look the hat of the rotor and the disc is one piece but has a floating design, compared to true two pieces which has bolts on it
05-15-2014, 02:47 AM
#10
MBWorld Fanatic!
MB claims the new design offers better heat distribution from rotor to hub, without hot spots at the bolted points.
Again, while some two-piece rotor designs allow radial movement at the connecting "buttons," as far as I know the P30 rotor was attached tightly at the bolts, allowing no float at all.
The technology for the boltless two-piece rotors on the P31 and 507 is the Brembo "dual-cast" process described here:
http://www.afsinc.org/content.cfm?ItemNumber=6874
Here are good pictures of the P31/507 dual-cast rotors:
https://mbworld.org/forums/suspensio...ther-amgs.html
Last edited by whoover; 05-15-2014 at 03:42 AM.
05-15-2014, 08:31 PM
#11
MBWorld Fanatic!
i wont be as brash as vaclav, lol, but i have to respectfully disagree with you. this is the definition of a floating rotor. it doesnt actually "float".
05-15-2014, 08:47 PM
#12
MBWorld Fanatic!
Here's a description of a proper floating rotor:
http://www.stableenergies.com/GiroDi...tinfo/GIR-KIT/
The floating bobbins are more complicated than the bolts in the P30 rotors, but the main reason they're only used on cars more exotic than ours is that they're noisy.
PS.: Another thread from the crowd that knows that 2-piece rotors come fixed and floating:
http://forums.rennlist.com/rennforum...-question.html
Last edited by whoover; 05-15-2014 at 08:55 PM.
05-15-2014, 09:04 PM
#13
The above brembo dual cast is a floating type
Read the article
It allows the ring to expand
It is similar the m3 e46 ones except instead of slots they used pins
The p30 uses bolts with some play
They are floating and similar to the ones on my rs4
Read the article
It allows the ring to expand
It is similar the m3 e46 ones except instead of slots they used pins
The p30 uses bolts with some play
They are floating and similar to the ones on my rs4
Last edited by Ingenieur; 05-15-2014 at 09:10 PM.
05-15-2014, 09:16 PM
#14
MBWorld Fanatic!
On a true floating rotor, there's enough degree of freedom to rock the rotor back and forth. The P30 certainly wasn't that kind of setup but might have have a few mils of looseness and I guess could qualify as floating. The P31 rotors, which I have actually laid my hands on, have no float whatsoever.
05-15-2014, 09:21 PM
#15
“As [a brake] disc gets hot, it wants to expand and grow,” said Brian Burke, technical driector for Brembo’s North American operations. “But since these materials have different expansion rates, the disc grows dynamically as you hit the brakes. It grows where it wants to grow, which reduces the thermo-mechanical stresses in the rotor. Picture an L-shape. What it wants to do is go back to a straight line, but what we have here is a symmetrical design that grows radially. It grows in the direction it wants to, so it gives zero axial deformation.”
That is from the article
The play is very small and the freedom of movement is only axially outward
It can't be moved by hand
It is floating
That is from the article
The play is very small and the freedom of movement is only axially outward
It can't be moved by hand
It is floating
Last edited by Ingenieur; 05-15-2014 at 09:27 PM.
05-15-2014, 11:00 PM
#17
MBWorld Fanatic!
How much better, objectively, are the 507 rotors, in comparison to say, the rotors on the standard LCI C63?
Calipers are identical (aside from the paint job), correct? Brembo 6-piston fixed front and 4-piston fixed rears?
Calipers are identical (aside from the paint job), correct? Brembo 6-piston fixed front and 4-piston fixed rears?
05-15-2014, 11:39 PM
#18
MBWorld Fanatic!
“As [a brake] disc gets hot, it wants to expand and grow,” said Brian Burke, technical driector for Brembo’s North American operations. “But since these materials have different expansion rates, the disc grows dynamically as you hit the brakes. It grows where it wants to grow, which reduces the thermo-mechanical stresses in the rotor. Picture an L-shape. What it wants to do is go back to a straight line, but what we have here is a symmetrical design that grows radially. It grows in the direction it wants to, so it gives zero axial deformation.”
That is from the article
The play is very small and the freedom of movement is only axially outward
It can't be moved by hand
It is floating
That is from the article
The play is very small and the freedom of movement is only axially outward
It can't be moved by hand
It is floating
http://www.essexpartsblog.com/news/c...ng-brake-discs
The P31 has none. Zero axial deformation has nothing to do with axial and radial freedom. It's about a bimetallic construction not warping or coming apart.
Here's a demonstration of a true floating rotor versus a "floating" rotor on a motorcycle. Float is not measured in microns.
05-15-2014, 11:44 PM
#19
MBWorld Fanatic!
The composite rotors are about 5 pounds lighter. The reduction in unsprung weight is probably the biggest difference. Aluminum also dissipates heat better so the hats acts as a heat sink, keeping the brakes cooler. This is another advantage of the dual-cast P31/507 rotors with an intimate connection between disk and hat.
05-16-2014, 12:27 AM
#20
MBWorld Fanatic!
A floating rotor normally has about 6-8 mm of movement. http://www.essexpartsblog.com/news/c...ng-brake-discs The P31 has none. Zero axial deformation has nothing to do with axial and radial freedom. It's about a bimetallic construction not warping or coming apart. Here's a demonstration of a true floating rotor versus a "floating" rotor on a motorcycle. Float is not measured in microns. Video Link: https://www.youtube.com/watch?v=jJPCy2AsULo
05-16-2014, 10:03 AM
#21
A floating rotor normally has about 6-8 mm of movement.
The P31 has none. Zero axial deformation has nothing to do with axial and radial freedom. It's about a bimetallic construction not warping or coming apart.
Here's a demonstration of a true floating rotor versus a "floating" rotor on a motorcycle. Float is not measured in microns.
Full Floating Rotor VS Stock "Floating" rotor - YouTube
The P31 has none. Zero axial deformation has nothing to do with axial and radial freedom. It's about a bimetallic construction not warping or coming apart.
Here's a demonstration of a true floating rotor versus a "floating" rotor on a motorcycle. Float is not measured in microns.
Full Floating Rotor VS Stock "Floating" rotor - YouTube
the largest expansion is perhaps 1 mm, 1/2 each radius
if it moved 4 the pad would be riding off the disc surface on the inside ridge
the P30, P31 and 507 are all floating
just different methods
one uses a cast pin to allow radial expansion
the other slottled bolts
weight reduction is not enough cost justification alone to go to the trouble of a 2 piece, especially when it would cost no more to make it floating since all you have to do is modifiy dimensions when casting or machining
Last edited by Ingenieur; 05-16-2014 at 10:37 AM.
05-16-2014, 10:07 AM
#22
you can see clearly the hub vanes that extend into the disc
they are not constrained
the allow the disc to 'float' or expand radially unrestricted
and the hub can do the same (at a greater rate than the disc actually)
they are not constrained
the allow the disc to 'float' or expand radially unrestricted
and the hub can do the same (at a greater rate than the disc actually)
Last edited by Ingenieur; 05-16-2014 at 10:38 AM.
05-16-2014, 10:10 AM
#23
here's the other type
you can clearly see there is a bit of slop radially
it is not a rigid joint, the flex clip give some play
in this one you can see a gap towards the hub center
the disc expands BOTH inward and outward
and the hub can expand outward (see the gap)
you can clearly see there is a bit of slop radially
it is not a rigid joint, the flex clip give some play
in this one you can see a gap towards the hub center
the disc expands BOTH inward and outward
and the hub can expand outward (see the gap)
Last edited by Ingenieur; 05-16-2014 at 10:40 AM.
05-16-2014, 10:18 AM
#24
coefficient of expansion of cast iron
5.9 x 10^-6 in / in deg F
assume a 15" disc (380 mm) and a 1000 F rise, the ring is ~5" x 2
10 x 5.9 x 10^-6 x 1000 F = 0.06' ~ 1.5 mm
each side
0.4 mm inward and outward
aluminum has twice the coef of exp
hence the gap on the bottom of the slot
as the disc comes towards the center a bit the hub will go outward
the hub might grow another 0.5 mm outward
5.9 x 10^-6 in / in deg F
assume a 15" disc (380 mm) and a 1000 F rise, the ring is ~5" x 2
10 x 5.9 x 10^-6 x 1000 F = 0.06' ~ 1.5 mm
each side
0.4 mm inward and outward
aluminum has twice the coef of exp
hence the gap on the bottom of the slot
as the disc comes towards the center a bit the hub will go outward
the hub might grow another 0.5 mm outward
Last edited by Ingenieur; 05-16-2014 at 10:44 AM.
05-16-2014, 01:24 PM
#25
MBWorld Fanatic!
It's really not that complicated. If you try to rock the iron part of a P31 rotor it does not move at all. And that's at room temperature. The (small) space between the hub and disk will get tighter when it gets hot. For all intents and purposes, it's a solid structure like a bimetallic euro coin.
You can call that "floating" -- apparently you wouldn't be the only one. I don't.
You can call that "floating" -- apparently you wouldn't be the only one. I don't.
