StephenK

The SBC brakes on the SL's, what is so great about them. I was recently in for some service and when leaving the service manager made a comment that the brakes on the SL600 are probably the best in the world. What is the big deal about these brakes and why are they better than normal brakes.

Chris 45971

Not sure of the specifics exactly, but the brakes on the SL are electronically controled and can stop the car from sprint to stop with pretty much any road car in the world. Very unusual for a car that is as heavy as an SL. Check the skid pad numbers in some old issues of motor trend and you will see that pretty much nothing beats the SL number.

I'm sure that there are some here that can explain with all the specifics.

vraa

The SL55 F1 pulls a .90g on the skid pad. Not really that impressive, but wicked cool for a car of that size.

My X5 pulls in a .79 (probably less with my Michelins) and the LS430 does a .83 on winter tires.

A C5 Corvette Zo6 pulls a .98g's.

S500 does a .80 and the Phaeton does a .82g's.

Just some food for thought, pulled from random google sources.

tiggerfink

In my Motor Tend magazine, there are only about three cars that beat the SL500 in stopping from 60 MPHs to 0 by a couple of feet.

That’s impressive for a car that weights that much.

blueSL

The stopping power of a car depends on the the area of pad against the disc, the pressure being applied to the pads and how well the pad/rotor interface is working which depends on things like pad material and temperature.

Mercedes did research which showed that in a panic situation, drivers often do not press the brake as hard as they could, which means they could have stopped faster and maybe avoided an accident. Also, in a situation where the brakes are close to locking up, the pulsing of the brake circuit by the ABS caused alarm because they were not familiar with it and caused them actually to back off the pedal.

What SBC does is allow you to apply maximum retardation because there is no ABS pulsing through the brake pedal and the electronics can recognise emergency braking situations and apply more braking than you the driver are asking for. Add that to generously specified rotors and calipers (which apply braking pressure over a larger area), good tyres and you have the recipe for outstanding braking performance.

That SBC is good at stopping the car in an emergency has never been in doubt. Early incarnations of it though got in the way of smooth driving and a progressive braking performance in normal driving situations. This has since been improved but some (myself included) still feel that the lack of feeback through the pedal does not warn you about what is happening. Still, if a truck pulls out of a side turn without looking, you'll be pleased you have SBC.

There won't be any more cars with SBC - the E Class, SL, Maybach and SLR have it but it is now deemed to be too expensive a system so cheaper alternatives are being looked at. The next S Class will give us clues where Mercedes is headed in this direction.

carlosfernandez

Thanks for the explication.

StephenK

I read this on a web page talking about SBC. I know I never saw this message in my display:

SBC HOLD

A "drive-away assistant" prevents the vehicle from rolling backwards or forward when starting on a hill or steep incline. A firm push onto the brake pedal, and the car remains stopped, even when taking the foot off the brake pedal, until the driver accelerates and the vehicle begins to roll. When set, the instrument cluster indicates SBC HOLD. I like using this function and miss it when switching back to other cars. As far as I know it was first introduced in the spring of 2003 in the 04 E-class Estate and lateron in the 2004 SLs.

blueSL

I think it was one of two functions like that, the other being to assist in crawling traffic by stopping the car creeping forwards. They were not present in the earliest SBC, my car does not have them and I do not know whether 05's do. If they are not in your car, it might be another example of MB de-contenting the car on the basis that the less there's in there, the less there is to go wrong.

On the face of it, these sound simple functions, but "a firm push on the brake pedal" means different things to different people, so I can imagine owners complaining to their dealer that SBC doesn't work where in fact they are not pressing hard or firmly enough all the time.

CASL55

I've read about this feature several times on this and other fora, but have never run across anyone in the US who has it. I suspect that MBUSA decided that US drivers couldn't cope with it, or that they somehow might get sued over it.

I had a similar feature in a 745i that I had once, and liked it. The 745 didn't have brake-by-wire, so they implemented it with a electromagnetic emergency brake. Worked fine, and you could use the iDrive to set up a mode where you could turn it on and off with a button on the steering wheel.

Jim

Kar don

StephenK, Those SBC functions are not available in the US (probably for legal reasons).

BTW, not sure why skidpad numbers were being referenced as they have no relevance to braking power/stopping ability.

FYI Skidpad definition - A large area of smooth, flat pavement used for various handling tests. Roadholding is measured by defining a large-diameter circle (Car and Driver uses 300 feet) on the skidpad and measuring the fastest speed at which the car can negotiate the circle without sliding off.

tiggerfink

I hope MB keeps the SBC brakes. They stop great when they are working. The SL500 stops at 108 ft from 60 to 0. That is great for a car that weighs like a hippo in the car world.

Below are the results on the 60 to 0 brake test.

Corvette Z6 107
Viper SRT 97
Ferrari Challenge 107

steph280

When I took delivery of my 05 E class, I immediately noticed the humming noises coming from SBC brake being primed by the pump. While the SBC brake system offers great performance, I wonder how reliable they will be in the long run. All these added components outta cause some headaches down the road.

tiggerfink

They are noisy. I had the car in the garage and when I touch the door handle of my car the SBC started to do its thing. I guess the SBC gets activated when I touch the door handle because of the keyless go.

carlosfernandez

That's the noice? I didn't know.

blueSL

What's happening is the hydraulic pump is bringing the pressure up to the required level and the pads are pessed closer to the rotors. They warn you not to cycle the ignition when working on the brakes because your fingers could easily get crushed. The forces required to stop an SL will make mincemeat of your fingers. The braking system works at a pressure of 160 bar, which is more than 2300 psi...

carlosfernandez

That's really interesting. Thanks for the info.

tiggerfink

I thought my car was broken when I heard all that noise.

RadSteve

2320 psi actually! ouch.