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Video History-Suspension 1
Video History-Suspension 2
Video History-Suspension 3
Video History-Suspension 4
Video History-Suspension 5
Video History-Suspension 6
Video History-Suspension 7

Video Undercarriage 1
Video Undercarriage 2
Video Steering Wheel 1
Video Steering Wheel 2
Video Steering Lock
Video Steering
Video Safety Steering
Video Rack Pinion Steering
Video Steering Ratio 1
Video Steering Ratio 2
Video Steering Ratio 3
Video Ball Steering
Video Worm Roller Steering
Video Hydraulic Power Steer. 1
Video Hydraulic Power Steer. 2
Video Electr. Power Steer. 1
Video Electr. Power Steer. 2
Video Electr.-hydraulic Pump
Video Torque (power steer.)
Video Electr. Stab. Program
Video Finger Steering
Video One-piece Track Rod
Video Four Wheel Steering 1
Video Four Wheel Steering 2
Video Four Wheel Steering 3
Video Dry Joint
Video History
Video Suspension control 1
Video Wheel positions
Video Suspension
Video Spring systems
Video Electr. Air Suspension
Video Center of Gravity
Video Oblique/lateral drift angle
Video Elasto-kinematics
Video Elk Test
Video Wheel Bearing 1
Video Wheel Bearing 2
Video Wheel Bearing 3
Video Wheel Bearing 4
Video Ind. pulse sensor
Video Wheel sensor 2
Video Transversal Axis
Video Suspension Carrier
Video Below View
Video Adj. suspension
Video Stabilizer 1
Video Stabilizer 2
Video Double-wishbone 1
Video Double-wishbone 2
Video Double-wishbone 3
Video Air suspension truck
Video McPherson Strut 1
Video McPherson Strut 2
Video McPherson Strut 3
Video McPherson Strut 4
Video Trailing Arm
Video Twist-beam Rear Axle
Video Space Arms
Video Multilink Axle
Video Semi-trailing Arm Axle
Video Rear-wheel Drive
Video Electr. Stab. Program
Video ABS/ESP-Hydr. Unit
Video One-arm Swing. Fork
Video Formula-3 Racing Car
Video Pend. Wheel Suspen.
Video Torson Crank Suspen.
Video DeDion Axle 1
Video DeDion Axle 2
Video Rigid Axle 1
Video Rigid Axle 2
Video Rigid Axle 3
Video Rigid Axle 4
Video Rigid Axle 5
Video Self steering axle
Video Track rod joint
Video Springs
Video Coil Spring 1
Video Coil Spring 2
Video Coil Spring 3
Video Leaf Spring
Video Torsion Bar Spring
Video Rubber Suspension
Video Hydropn. Suspension
Video Air Suspension 1
Video Air Suspension 2
Video Shock Absorber 1
Video Shock Absorber 2
Video Shock Absorber 3
Video Shock Absorber 4
Video Shock Absorber 5
Video Single-tube Damper 1
Video Single Tube Damper 2
Video Double-tube Damper
Video Shock Absorber Piston
Video Friction Absorber
Video Tyres
Video Wheel Positions

Video Tyre Calculation
Video Inch -> mm
Video Slip
Video Axle Load Distrib.
Video Payload Distrib.
Video Roller Resistance 2

Video Wheel suspension 1
Video Wheel suspension 2
Video Wheels 1
Video Suspension 1
Video Suspension 2
Video Suspension 5
Video Steering 1
Video Steering 2

          A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

  History Suspension 4

Previous page

Apart from the front- and rear track-width, one dimension is particularly important, that is the wheelbase. The area between these measurements is by far the more expensive, because here, the stability and the torsion are in question. If needs be, this can be extended to the front or to the rear by using a plastic component. The wheelbase determines the actual amount of space later available in the car, that means, the distance from the front seat back-rest to the clutch pedal or from the the rear- to the front seat back-rest.

The overhang to the front and rear are actually only of importance in few vehicles, e.g., in off-road vehicles. However, even here they can be slightly slanted upwards, to ensure that the slope- or ramp angle is large enough. Indeed, the appearance is then bound to suffer. Rear overhangs can sometimes be alarmingly large, particularly, e.g., when a light transporter is converted into a bus for 20 or more passengers. In this case, the overall maneuverability is also restricted.

By the way, although the wheelbase is sometimes measured exactly to the millimeter, in most constructions these measurements are by no means fixed. When the rigid rear axle is guided by trailing arms it changes if the springs are compressed. Only if the wheels were absolutely vertically guided, would there be no change in the wheelbase. This has been done on the front axle, but on the rear axle it can be excluded. Even leaf-springing shifts the rigid axle a little, mostly to the rear.

The lateral movement of the wheels can be even more pronounced, because also the track-width is not constant when a compression takes place. This, by the way, mostly has a more marked effect on the suspension, e.g., it can cause the straight-line driving performance to worsen and also further effect the steering, we won't even mention the increasing of the rolling resistance. A very important factor of the suspension layout, is the changing of the camber and other parameters.

Let's remain, for the moment, with the center of gravity, the importance of which was also explained in the article about the position of the engine. It should of course, be as low as possible. Just how far the quest for a low center of gravity goes, can be well seen in cleverly worked out racing car technology. The reason why a dry-sump lubrication was introduced, is that a smaller, or in fact, non-existent oil bath, would allow the engine to be mounted lower. Using the same argument, a multi-disc clutch with a smaller diameter is sometimes installed instead of a larger single-disc clutch.

Let's take a closer look at the behaviour of the front- and rear axle. Looking at the two separately, the suspension components carry out pretty complicated movements, there is however, looking from the rear, one point, around which everything turns when the springs are compressed, this is the 'momentary center-point'. Should one, e.g., have two wishbones, then this point would be the intersection of both extensions towards the inside. If this point is joined to the center of the tyre-contact area, this line in the vehicle center, would go through the 'sway poles' or rolling center. Both the rear- and the front axles have this point. A longitudinal axis running through these two points must be exactly in the center of the rolling movement. It joins all the points which do not change when the car body inclines.

Why is a specific point called the 'momentary center-point'? One 'pole each' is also part of the earth's axis and the expression 'momentary' refers to a quite unique situation which is taking place right now. If any parameter is changed, and there are many, the point is somwhere else in relationship to the vehicle and must, by projection, be re-determined. The advantage is however, that with the help of this point the speed and the acceleration can be be calculated at almost any point of the suspension. Indeed, one moment later the curve will have changed a little and possibly be more severely crossed, it must then be determined anew.

Using the above picture of the rear axle of the 1932 DKW-Front, I would like to explain just how important the two sway-poles are. You may consider this transverse leaf-spring to be unusually highly mounted. Due to the missing boot-lid, it certainly does unnecessarily limit the access to the inside of the luggage compartment. Why then, did the designer still place it so high?

Lateral incline is felt to be unpleasant for the passengers in a car, particularly as soft springing at that time was normal, because of the bad road conditions. Should the rear-axle kinetics, through the placing of the transverse leaf-spring be thus altered, so that the center of gravity coincided with the sway-pole, the additional incline momentum around the sway-pole could, at best, be zero. For this reason, this was called, indeed somewhat exaggeratedly, a 'floating-axle'. 06/12

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Translator: Don Leslie - Email:

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