The new CLK-Class (W209): Chassis & Control Systems

Chassis and control systems: right on track

Three-link front suspension for dynamic handling and supreme comfort

Enhanced safety and lighter weight thanks to sophisticated rack-and-pinion steering

Optional sports suspension for all model versions

ESP® and other latest-generation active safety systems

Brake system with immense power reserves

16-inch light-alloy wheels and mixed-profile tyres as standard

CLK 55 AMG with sports suspension and high-performance brakes

In terms of agility, straight-line stability, steering precision, road roar, tyre vibration and braking power – in short, practically all areas of chassis technology – the new CLK-Class achieves peak-performance figures which add up to ensure one thing above all: an even more dynamic driving experience.

The Mercedes engineers spared no expense in newly developing or further improving the axles, steering and brakes, to exceed the already high standards set by the predecessor model. In doing this, they were able to call upon tried-and-tested systems from the Stuttgart manufacturer's passenger car line-up and adapt these systems for use in the new Coupé. This involved the following:

Replacing the previously installed double-wishbone design with state-of-the-art three-link front suspension with McPherson struts, thus enabling major advances, particularly with respect to wheel location, comfort and steering precision. Furthermore, this design provides greater deformation paths in the area of the lower links, enabling the front end of the CLK Coupé to absorb more impact energy than previously. The forwards-slanting tension struts on the front axle and the integral support – to which front axle components, the steering gear and the engine mounts are attached – are made of aluminium.

The Mercedes engineers have replaced the previously fitted recirculating ball-type steering with power-assisted rack-and-pinion steering which is even more responsive and thus better suits the dynamic character of the new Coupé. What is more, this system is lighter and offers added safety benefits in the event of a frontal collision. Mercedes-Benz offers the option of speed-sensitive parameter steering for the CLK-Class (standard in the CLK 500). This makes manoeuvring or parking practically child's play. At 380 mm, the steering wheel diameter is 10 mm smaller than in the preceding model. The steering wheel rim is made from an combination of steel and magnesium, which deforms in a predetermined manner in the event of a collision, thus reducing the risk of injury to the driver.

In conjunction with the newly developed front axle, the longer wheelbase and the standard-fitted Electronic Stability Program (ESP®), the tried-and-tested multi-link independent rear suspension ensures a high degree of active safety, dynamism and comfort. The track rods, hub carriers and subframe for the rear axle have also been radically reengineered by the Mercedes engineers. New kinematics and elasto-kinematics, largely due to the use of optimised bearings and mounts, ensure even better vibration response and reinforce the understeer characteristics of the Coupé. All engine versions available with the new CLK-Class are equipped with anti-roll bars.

Facts and figures: the main chassis data for the new CLK-Class

Whilst the front and rear track width remain almost the same as for the predecessor model, the wheelbase has been extended by 25 mm. The new CLK-Class has mixed-profile tyres as standard – these are in 17-inch format for the new top-of-the-range V8 CLK 500 model.

	New CLK-Class	Preceding series
Wheelbase mm	2715	2690
Front track width mm	1493	1505
Rear track width mm	1474	1474
Turning circle m	10.76	10.70
Tyre size*	Front: 205/55 R 16 Rear: 225/50 R 16	205/55 R 16
Wheel size*	Front: 7 J x 16 Rear: 8 J x16	7 J x 16

*e.g. for the CLK 320

Factory-fitted sports suspension for further enhanced driving dynamics

Motorists who fancy themselves as racing drivers can order the CLK Coupé chassis with tauter suspension and damper settings. Mercedes-Benz supplies this sports suspension set-up, in which the body is 15 mm lower at the front and rear axle, as an option for all lines and model versions. Spring rates for the sports suspension are five percent higher.

The CLK 55 AMG is to be launched with high-performance AMG sports suspension. Enlarged anti-roll bars on the front and rear axles, coupled with specially tuned springs and gas-filled shock absorbers, ensure supreme roadholding and incorporate the technical advances necessary for sporty handling.

Brake technology for the ultimate in performance

In terms of size, technology and equipment, the Mercedes engineers have tuned the brakes to each of the different engines and the wide range of outputs available with the new CLK-Class. For instance, the flagship CLK 500 has 4-piston fixed-caliper disc brakes on the front axle, of the kind used for the SL 500 Roadster. The eight-cylinder model has 2-piston fixed-caliper disc brakes on the rear axle. The diameters of the internally ventilated front and rear brake discs are 345 and 300 mm respectively.

The technology used for the tandem brake booster (7/8-inch) made of aluminium is lifted from the S-Class. It is equipped with an electronically controlled solenoid valve that enables particularly precise application of the brake pressure. The main brake cylinder – also made of aluminium -- is fitted with a pretensioned compression spring between the primary and secondary pistons. In contrast to conventional systems, in which the secondary piston only moves due to the pressure in the primary circuit, both brake circuits are activated simultaneously in the new CLK-Class. Substantially shorter pedal travel is just one of the benefits of this immediately obvious to the driver.

The development team drew on its experience in motorsport when designing the brakes for the high-performance CLK 55 AMG Coupé. And the upshot: four-piston fixed-caliper disc brakes on the front axle, with internally ventilated and perforated brake discs measuring 345 mm in diameter, and two-piston fixed-caliper disc brakes at the rear, also with internally ventilated disc brakes (diameter 300 mm). This means the brake system on the AMG Coupé can rise to almost any challenge with an impressive maximum deceleration of 10.5 metres/second².

Front axle	CLK 200 CGI CLK 200 KOMPRESSOR,	CLK 270 CDI, CLK 240,CLK 320	CLK 500	CLK 55 AMG
Version	Single-piston sliding-caliper, internally ventilated	Single-piston sliding-caliper, internally ventilated	4-piston fixed caliper, internally ventilated	4-piston fixed-caliper, internally ventilated and perforated
Wheel cylinder Ø mm	57	57	44/40	44/40
Brake disc - diameter mm - thickness mm	288 25	300 28	345 30	345 30
Rear axle
Version	2-piston fixed-caliper, solid	2-piston fixed-caliper, solid	2-piston fixed-caliper, internally ventilated	2-piston fixed-caliper, internally ventilated
Wheel cylinder Ø mm	36	36	42	42
Brake disc - diameter mm - thickness mm	278 9	290 10	300 22	300 22

Electronic control systems for superlative active safety

As is the case with all state-of-the-art Mercedes passenger cars, the new CLK-Class is equipped with the best and most highly effective active safety systems available – as standard. They reduce the risk of skidding when cornering, hold the Coupé safely on track when braking, improve starting on slippery surfaces and reduce the emergency-stopping distance. This high-performance technology is an important part of the Mercedes-Benz safety concept and actively helps to prevent road accidents.

The Electronic Stability Program (ESP®) uses various sensor signals to detect dangerous situations even earlier and faster than the most experienced of drivers can, intervening automatically with the utmost precision to stabilise the vehicle. It does this through precisely modulated brake pulses on one or more wheels and by reducing the engine torque. The new CLK Coupé is equipped with latest-generation ESP® which operates extremely harmoniously thanks to its supremely smooth response.

The Anti-lock Brake System (ABS) prevents the wheels from locking up during emergency braking and works as reliably on dry tarmac as it does on wet surfaces or black ice. As a result, the Coupé retains directional stability at all times -- even under maximum deceleration.

Acceleration Skid Control is part of the Electronic Stability Program and prevents the driven wheels from spinning when starting off or accelerating. If the driver accelerates too abruptly and one of the driven wheels starts to spin, this wheel is braked by ASR until sufficient traction is re-obtained. In addition, the engine torque is also reduced, depending on the situation on the road.

Brake Assist (BAS) is activated if a critical situation arises and the driver is too slow or not hard enough on the brake pedal. In such instances, the system automatically provides maximum-power braking within a fraction of a second, thus substantially reducing the car's stopping distance.

Light-alloy wheels and wide-base tyres for a distinctly sporty appearance

Further special features of the new CLK-Class designed to further enhance the sporty nature of the Coupé include different-sized tyres on the front and rear axles. The standard equipment package includes 205/55 R 16 tyres on the front axle and 225/50 R 16 tyres at the rear. The top-of-the-range V8 CLK 500 model has 17-inch tyres, namely size 225/45 R 17 at the front and 245/40 R 17 at the rear. The Mercedes engineers have adapted the design of the standard-fitted light-alloy wheels to suit the individual character of each line: they fit the ELEGANCE model with smart seven-hole rims, whilst the AVANTGARDE line comes with a distinctly sporty five-spoke-rim look that makes it really stand out.

Optional equipment for all model versions includes special 17-inch light-alloy wheels or 18-inch AMG light-alloy wheels. The CLK 55 AMG catches the eye with its 18-inch light-alloy wheels, with new twin-spoke design as standard or classic five-spoke design as an option. This high-performance Coupé has size 255/40 R 18 tyres on the front axle and size 255/35 R 18 on the rear axle.

Model	Tyres and rims
CLK 270 CDI, CLK 200 KOMPRESSOR, CLK 200 GCI, CLK 240, CLK 320	Front: 205/55 R 16 on 7 J X 16 Rear: 225/50 R 16 on 8 J x 16
CLK 500 or optional for all other model versions with special rims	Front: 225/45 R 17 on 7.5 J x 17 Rear: 245/40 R 17 on 8.5 J x 17
CLK 55 AMG	Front: 225/40 R 18 on 7.5 J x 18 Rear: 255/35 R 18 on 8.5 J x 18

Further standard equipment for the new CLK-Class includes the innovative TIREFIT repair kit in place of the conventional spare wheel. The spare wheel recess in the boot can therefore be used as a stowage compartment. Mercedes-Benz still supplies the spare wheel as a no-cost option.