Press Kit: The new Mercedes-Benz R-Class
Munich
Oct 24, 2005
Suspension: Floating on air
  • Newly developed double-wishbone front axle
  • Four-link rear axle with air suspension as standard
  • AIRMATIC and the Adaptive Damping System as an optional extra
  • 17 and 18-inch light-alloy wheels as standard
A wide track, a long wheelbase and newly developed axles - these factors ensure that the R-Class meets even the highest expectations where both handling dynamics and ride comfort are concerned.
The front wheels are located by a newly developed double-wishbone suspension with a high-mounted upper wishbone. This is made of forged aluminium, while the lower wishbone and steering knuckle are of nodular cast iron. The front axle, steering gear, engine and transmission are mounted on an integral subframe of high-strength sheet steel.
This front suspension with its high control arms is equipped with spring struts with a long spring travel and highly effective rubber mounts. The spring struts contain cylindrical coil springs, single-tube gas-pressure shock absorbers and large upper bearings. The torsion bar stabiliser is attached to the spring strut by a linkage.
The steering gear of the new R-Class is positioned in front of the wheel centre, and therefore where it can support the slight but easily controlled understeer on bends. The servo-assisted rack-and-pinion steering has a variable ratio which operates a little more directly in the central position than in the outer positions. Additional comfort is provided by the standard-fit speed-sensitive power steering, which, at speeds below 100 km/h, adapts the steering effort as a function of vehicle speed. This is made possible by an electronically controlled valve: the lower the speed, the higher the servo effect. Accordingly only half the steering effort is required when parking the vehicle as when driving on the motorway, where the speed-sensitive power steering provides a good feeling of road contact.
Mercedes-Benz has developed a reach and height-adjustable four-spoke steering wheel with a diameter of 385 millimetres for the new R-Class whose die-cast magnesium structure is designed to deform specifically during a frontal collision, thereby reducing the risk of injury to the driver. The steering wheel is an important part of the operating and display concept with its conveniently placed, illuminated buttons, as it allows various functions such as the radio, car telephone or the central display in the instrument cluster to be operated by slight thumb pressure. The newly developed steering column collapses telescopically by up to 82 millimetres in the event of a frontal collision.
The four-link rear axle of aluminium and forged steel
The rear axle is mounted on a subframe which is effectively isolated from the bodyshell by four rubber mounts. Mercedes engineers have developed a four-link suspension design which basically consists of the following elements:
  • Lower wishbones: These axle components are made from aluminium.
  • Upper link level: This is an assembly of sheet steel camber struts and forged steel radius/diagonal struts.
  • Track rods: These are located behind the wheel centre and are of welded tubular construction.
  • The four-link rear axle is equipped with air suspension, separate single-tube shock absorbers and a torsion bar stabiliser.
    AIRMATIC air suspension automatically lowers the body from 120 km/h
    The AIRMATIC air suspension system (optional) developed by Mercedes-Benz not only offers significantly improved ride comfort, but also improves the aerodynamics and therefore fuel consumption at higher speeds. The system operates on a speed-dependent basis and automatically lowers the ride height by 20 millimetres when 120 km/h is reached. When the speed falls below 60 km/h the body is raised to its normal level again. At the touch of a button the driver is able to raise the ride height by a maximum of 50 millimetres, in order to obtain more ground clearance, for instance when driving on rough tracks. AIRMATIC lowers the body to its normal level when the speed reaches 40 km/h. Other features of the air suspension system include an automatic all-round level control function, which ensures that the suspension travel remains constant even when the vehicle is heavily laden.
    ADS adjusts the shock absorbers to suit the driving situation
    AIRMATIC works as standard in tandem with the Adaptive Damping System (ADS), which controls the shock absorber response in line with requirements while taking the road surface, driving style and load into consideration. Selectable solenoid valves in the shock absorbers enable the rebound and compression damping to be modified according to the situation, which considerably reduces body movements. A "skyhook" algorithm controls the damping forces at each wheel in such a way that the wheel-induced forces acting on the vehicle body are reduced. Thanks to this precise control for each individual wheel, the two front wheels can for example be damped more heavily than the rear wheels to reduce the tendency of the body to dive when braking. Depending on the control command, the valves are able to select one of four sets of response characteristics within an extremely short response time of less than 0.05 seconds:
    • Stage 1: Comfortable suspension action with small body movements and low acceleration values owing to soft compression and rebound settings.

    • Stage 2: Skyhook mode - soft rebound setting and a hard compression setting.

    • Stage 3: Skyhook mode - soft compression setting and hard rebound setting.

    • Stage 4: Hard rebound and compression setting to reduce wheel load fluctuations when cornering at speed.
    When body movements are small the new R-Class operates in ADS stage 1. If body acceleration values exceed a certain level, the system changes over to the skyhook algorithm and uses its rapid-response solenoid valves to continuously switch between the second and third damping stage to compensate the rolling and pitching movements of the vehicle body. In addition the driver is able to influence the changeover thresholds between the four ADS stages, as well as the spring rate, by pressing a button in the centre console. There is a choice of three modes: "Auto", "Sport" and "Comfort".
    The variable ADS gas-pressure shock absorbers and air spring are integrated into a spring strut at the front axle of the new R-Class. At the rear axle the ADS shock absorber is located behind the air spring. Torsion bar stabilisers are also used at both the front and rear.
    The R 500 is equipped with four internally ventilated disc brakes
    The Grand Sports Tourer is equipped with efficient, internally ventilated front brake discs with a diameter of 330 millimetres in the six-cylinder models. In the R 500 their diameter is 350 millimetres. At the rear axle Mercedes-Benz uses solid disc brakes with a diameter of 330 millimetres, and in the R 500 these too are internally ventilated.
    The braking system at a glance:
     

    R 320 CDI, R 350

    R 500

    Front axle
    Brake piston diameter
    Brake disc diameter x thickness


    2 x 44 mm
    330 x 32 mm
    internally ventilated


    2 x 44 mm
    350 x 32 mm
    internally ventilated

    Rear axle
    Brake piston diameter
    Brake disc diameter x thickness


    40 mm
    330 x 14 mm
    solid


    42 mm
    330 x 22 mm
    internally ventilated

    Light-alloy wheels and wide-base tyres emphasise the dynamic appearance
    Even the basic version of the new R-Class is equipped with 17-inch light-alloy wheels and size 235/65 R 17 wide-base tyres. The top-of-the-line eight-cylinder R 500 features 18-inch light-alloy wheels with size 255/55 R 18 tyres. An overview:
     

    R 320 CDI, R 350

    R 500

    Standard equipment

     

    Seven-spoke design
    7.5 J x 17 ET 56,
    235/65 R 17

    Five-twin-spoke design
    8 J x 18 ET 67,
    255/55 R 18

    Optional extra

    Ten-spoke design
    8 J x 18 ET 67, 255/55 R 18

    Sports package
    (optional)

    Five-spoke design
    8 J x 19 ET 67, 255/50 R 19

    ESP® with tyre pressure loss warning function
    ABS, ASR, ESP®, Brake Assist - these well-proven dynamic safety systems devel-oped by Mercedes-Benz are standard equipment in the new R-Class. In its latest version, the Electronic Stability Program also monitors the tyre pressure: the system continuously compares the wheel rotation speeds, which mainly depend on the vehicle speed, vehicle load and tyre pressures. It is therefore able to detect any significant deviations. In addition the control unit automatically monitors other dynamic parameters such as the lateral acceleration, yaw rate and wheel torque in order to diagnose any pressure loss in a tyre reliably, though this system does not measure the actual air pressure in each tyre. If a loss of pressure is detected in a tyre, a warning appears in the cockpit's central display: "Tyre pressure, check tyres." This warning function for tyre pressure loss based on ESP® technology is standard equipment in the new R-Class.
    An optional electronic tyre pressure monitoring system is also available; it uses sensors in the tyre valves to monitor both the air pressure and temperature inside the tyre. The data are transmitted by radio to special antennae in the wheel arches which are linked to a microprocessor. This distinguishes between the signals on the basis of their individual signature, and is therefore able to provide the driver with specific information about the air pressure in each of the four tyres via a cockpit display.
    Your Media Contact
    Wolfgang
    Zanker
    Head of Mercedes-Benz Cars Series, Test Vehicles Management, Sports Communications
    Phone: +49 711 17-75847
    Fax: +49 711 17-91602
    Christian
    Anosowitsch
    Model Series ML-, G-, GL-, GLK-, R-Class
    Phone: +49 711 17-75849
    Fax: +49 711 17-98646
    Actions
    ALL press kit contents
    © 2014 Daimler AG. All rights reserved. Provider | Legal Notices and Terms | CookiesPrivacy Statement, | Terms of Use