Chassis and suspension: Comfort meets dynamism

Mar 13, 2014
The suspension is all-new and offers exemplary suspension and ride comfort combined with outstanding driving dynamics. The new C-Class comes across as light-footed and agile, delivering a high level of fun at the wheel on winding roads coupled with superb ride comfort in its segment.
A newly designed 4-link front axle plays a major part in the agile handling characteristics. The 4-link concept isolates the strut from the wheel location functions. Moreover, it ensures favourable axle kinematics: improved camber change allows higher cornering forces, for example, making the suspension respond more sensitively to steering movements and allowing a sporty, agile driving style. Since the kingpin inclination is also close to the wheel centre, this provides for large longitudinal force leverage and keeps the scrub radius small, thus minimising sensitivity to vibrations caused by tyre imbalances and fluctuations in braking force.
The 4-link front axle consists in the lower control arm plane of two individual links (pull rod and spring control arm). The strut braces against the transverse forged aluminium spring control arm. The stabiliser acts on the spring control arm. In the upper plane a forged aluminium wishbone takes on additional wheel locating functions. A rigid, weight-optimised integral carrier allows attaching components such as the engine, transmission and steering gear in a way that is most conducive to optimal dynamic handling.
Because the components of the new front axle are made of aluminium, they weigh about two kilograms less than a corresponding steel design. This enables a sensitive response. The reduction in weight also contributes to the high efficiency of the new C-Class.
An optimised multi-link independent rear suspension with 5-links ensures unsurpassed wheel location qualities and supreme straight-line stability. The rear axle carrier and the spring control arms are made of forged aluminium. A large rear-axle bearing contributes to isolating vibrations and thus to the outstanding NVH characteristics and ride comfort of the Saloon.
The Saloon of the new C-Class comes with steel springs and a DIRECT CONTROL suspension as standard. It is available in three variants:
  • as a comfort suspension with selective damping system which adjusts automatically to the condition of the road surface,
  • as an Avantgarde suspension with selective damping system, which combines high levels of comfort with sporty looks and
  • as a sports suspension, which is lowered by 15 millimetres and also features selective damping system and sports tuning. In addition, the sports suspension is combined with a more direct steering ratio to achieve maximum sportiness.
First air suspension in this category
Alternatively, the new C-Class is the first vehicle in its segment that can be fitted with an air suspension (AIRMATIC) on the front and rear axle. Thanks to electronically controlled, continuous variable damping at the front and rear, it offers outstanding road roar and tyre vibration characteristics even with the vehicle loaded. The driver can use a switch to select between the various damper characteristics: "Comfort", "ECO", "Sport" and "Sport Plus". The additional "Individual" setting allows the driver to configure the vehicle to suit personal preferences.
AIRMATIC also features all-round self-levelling for optimum ride comfort even with the vehicle loaded. It controls the ride height automatically in dependence of the speed and reduces fuel consumption on the motorway by lowering the vehicle, for example. This also improves safe handling. Furthermore, the ground clearance can be increased at the push of a button using the ride-height adjustment switch on rough roads or awkward ramps.
Since neither the air suspension struts at the front axle nor the free-standing air spring at the rear are responsible for wheel location and absorbing cornering forces, AIRMATIC offers outstandingly comfortable driving characteristics which are otherwise the reserve of the luxury segment. It smooths out expansion joints, asphalt patches and undulating asphalt caused by trucks braking at traffic lights.
Without impairing comfort, the adjustable damping can deliver a high level of dynamic handling. During evasive manoeuvres, the system adjusts, for instance, the damping forces to the vehicle's driving dynamics in fractions of a second.
Steering with a sporty character
All models of the C-Class family will feature an electromechanical Direct-Steer system as standard from now on. This combines road-speed-dependent power assistance from the speed-sensitive power steering system with a steering ratio that varies according to the given steering angle. The power steering assistance provided by the rack-and-pinion steering gear is controlled on-demand, thereby contributing towards efficiency.
Advantages of the electromechanical Direct-Steer system:
  • improved agility thanks to more direct steering response
  • comfortable handling and high levels of steering comfort at all speeds
  • considerable savings potential, since energy is only required when steering occurs
  • enables the use of innovative assistance systems, such as Active Parking Assist
STEER CONTROL provides steering clues in dangerous situations
The new C-Class comes standard-equipped with the STEER CONTROL steering assistance function. It can help the driver to stabilise the vehicle in difficult handling situations. To this end, the electronics determine in which direction the driver has to steer to defuse a critical situation, and introduces a corresponding steering-wheel moment into the steering that the driver feels clearly. In this way STEER CONTROL provides the driver with noticeable prompts in which direction to steer in order to stabilise the vehicle. If the vehicle oversteers, the steering wheel provides the driver with the prompt for correct countersteering until the vehicle is safely back on course. Frequently a vehicle is braked on a road surface with different friction (µ-split) on the left and right, generating a yawing impulse which turns the vehicle in the direction of the high friction. In this case the steering assistance system prompts the driver to turn the steering wheel in the appropriate direction to compensate for the yaw caused by the different friction. However, the steering assistance system never overrules the driver.
Fade-resistant brakes for short stopping distances
The brakes of the new C-Class meet high requirements with regard to stopping distance, response, fade resistance, directional stability and service life of the brake pads. Single-piston floating callipers at the front and rear axle with brake discs whose size is dependent on the engine provide for rapid deceleration. This task is handled by brakes with four-piston floating callipers in the C 250, C 250 BlueTEC, C 300 and C 300 BlueTEC HYBRID. This also applies to vehicles of the AMG Line design and equipment line, whose brake callipers bear Mercedes-Benz lettering.
The braking system of the C-Class comes as standard with ADAPTIVE BRAKE. It offers among other things
  • Hill-Start Assist which prevents the vehicle from rolling backwards on a hill and thus facilitates starting off
  • a HOLD function (standard with automatic transmission, with manual transmission in conjunction with cruise control optional extra), which holds the vehicle stationary without having to depress the brake pedal
  • a brake-drying function which regularly wipes the moisture from the brake discs to make full braking power instantly available
  • the pre-fill function lightly puts the brake pads into contact with the discs the instant the driver releases the accelerator quickly, and can consequently shorten the stopping distance during subsequent braking.
Electric parking brake with Comfort Go
For the first time the new C-Class is standard-equipped with an electric parking brake that offers convenience and weight benefits over a foot-operated parking brake. The electric parking brake is operated with a control element below the rotary light switch - pushing the control element sets the parking brake, pulling releases it. The driver can also use the automatic release function Comfort Go. It automatically releases the parking brake when the driver intends to start off.
Normally the parking brake engages completely and permanently at speeds below 4 km/h independent of the duration of the actuation. However, at higher speeds it can also be used for emergency braking. If it is activated at a speed of more than 4 km/h, the vehicle will decelerate with the service brakes of all four wheels including ABS and ESP® control interventions.
Additional functions of the brakes of the new C-Class:
  • As a torque vectoring brake it provides for additional safety at the limit by purposefully vectoring the torque between the wheels of the driven axle by means of one-sided brake interventions.
  • The adaptive brake light can warn vehicles following behind of strong braking and shorten their reaction time.
Mercedes-Benz C-Class: Chassis and steering
Mercedes-Benz C-Class: Chassis and steering
Mercedes-Benz C-Class: Chassis and steering
Mercedes-Benz C-Class, suspension
Mercedes-Benz C-Class, Front axle
Mercedes-Benz C-Class, Rear axle
Mercedes-Benz C-Class, Electromechanical Direct Steer system