2011 Mercedes-Benz SLS AMG: Suspension Walkaround
In the end, the $200,000 SLS AMG is like any other car in that I can jack it up, put jack stands underneath, yank the wheels off and have a good look at the mechanicals. The trick is getting my hands on the keys for a couple of days. As you can see above I managed to do just that.
This particular car came out of the west coast Mercedes-Benz press fleet and it's made the rounds. It has over 15,000 hard miles on the clock. More than a few celebrity posteriors have sat upon these red leather seats. One would assume it's been to the Grammys, the Golden Globe Awards and the Oscars, and we're pretty certain Adam Carolla flogged it during the taping of his yet-to-be-seen response to Top Gear, a show that will air on Speed if it airs at all.
So is there anything left? Let's have a look.
As you might expect, aluminum dominates the underside of the SLS AMG. Here we see a double wishbone front suspension made almost entirely of the stuff.
Forged aluminum upper and lower A-shaped control arms locate the wheel in 3D space. A reclined aluminum-bodied coil-over shock provides the necessary support and control.
The engine sits so far back in this machine that a front-mount steering rack placement (yellow) isn't a challenge at all.
Steel makes its first significant contribution in the form of a front stabilizer bar (green) and its associated drop link.
The forged aluminum upper control arm bolts to aluminum brackets which are in turn bolted to a cast aluminum section of the aluminum space frame. All told, the car's entire aluminum space frame weighs just 241 kg, otherwise known to us as 532 pounds.
And yes, 15,000 miles of hard driving and serious profiling have left it all a bit dusty.
The massive 15.4-inch rotors are of the two-piece variety, even though dozens of parts are necessary. Ten sets of spacers, clips and bolts allow the 1.4-inch thick ventilated, slotted and drilled cast-iron rotor to "float' on its aluminum hub.
Monstrous rotors demand humungous calipers, and the folks at AMG have obliged. These six piston (yellow x2) calipers feature an open pad window with a bridge bolt (white) that can be removed when it's time to change pads. The ears of the pads themselves feature tiny mass damper weights to quell vibration.
The AMG's 563-horsepower 6.2-liter V8 (yes, I know it says 6.3 on the side of the car, but the displacement is actually 6.2 liters) ... what was I saying? Oh, yes -- the V8 engine sits so far back that the shock towers (green) tie into a frame crossmember that spans across the engine bay entirely in front of the pulleys and accessories on the front of the motor.
The rear suspension is also made up of double wishbones and coil-over aluminum-body shocks.
This forged aluminum lower wishbone truly is shaped like a wishbone. The lower end of the Sachs aluminum shock (yellow) necks down to clear the driveshaft.
Double wishbones alone can't keep the rear wheels pointed straight ahead. In the front there's a steering rack, which is only straight when you want it to be.
Here in back you need a fixed toe-link (yellow) instead. The relative lengths of the upper arm, the lower wishbone and this link create a tiny measured amount of bump-steer, typically a wee bit of roll understeer to prevent the ass-end from swapping ends with the front.
Of course you can easily achieve that whenever you want by standing on the gas and boiling the rear tires with the stability control switched off. Or so I hear.
Like the front, the rear forged aluminum arms bolt to aluminum brackets that bolt to the aluminum space frame.
Like the front, steel is the material of choice for the stabilizer bar (yellow) and its drop link. Also the coil spring. Anything that sees a lot of torsional cycling is best made of spring steel.
Massive brakes adorn the rear of the SLS, but here the ventilated, slotted and drilled discs are one-piece cast-iron units. The brake calipers are 4-piston fixed units, but here the bridge (yellow) is fixed. You have to remove these calipers to change pads. Like the front, the ears of the rear pads have mass dampers connected to them.
It's no surprise that the wheel and tire package is huge. Continental ContiSport Contact 5P asymmetrical summer tires, sized 265/35ZR19, ride on 19-by-9.5-inch forged aluminum 10-spoke AMG wheels. The assemblies weigh 48.5 pounds, light for their size. And that's just the front.
In back you'll find 295/30ZR20 tires on 20-by-11-inch rims. These tip the scales at 57 pounds apiece. The forged wheels are not standard equipment, either. The option costs a mere $2,400, but who's counting in this price range?