HAWEKA 924 000 010, Operating Instructions Manual

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AXIS4000 W
HEEL
A
LIGNMENT
S
YSTEM
HAWEKA Wheel Alignment –AXIS4000
6
2 Suspension terminology
The suspension forms the point of contact between the vehicle and the road surface. The full power
of the engine is transferred to the road via the suspension, and forces generated from the road are
transmitted back to the vehicle through the suspension. The suspension is therefore subjected to an
enormous number of forces acting in different ways, and must therefore be maintained in perfect
condition.
Even under normal conditions, general operation of the vehicle can cause changes to the suspen-
sion geometry. Normal wear to parts (wheel bearings, king pins. etc.) can also lead to changes in
the suspension geometry. Incorrect steering and/or camber can not only damage the tyres, but also
adversely affect the accuracy of the steering behaviour.
The complex geometry of the wheel suspension and the many different driving styles of drivers
make it extremely difficult to establish the symptoms and probable causes. Tyre wear only indicates
that the tyres may be exposed to unusual friction forces. Although this may help the technician in his
diagnosis, it does not provide a direct route to the cause of the problem.
Assessment of the tyre profile only narrows down the cause of the problem. In all cases, a
visual check must be followed by axle measurement.
All these circumstances necessitate a suspension measurement with the aid of a wheel alignment sys-
tem. Special tools are not the only thing important to measuring procedures – the most important factors
of suspension measurement still include the user’s eyes, hearing and technical skill.
2.1 Suspension measurement terminology
Wheel alignment
Wheel alignment is crucially important for straight run-out of the wheels, good grip by the tyres in
bends and wear to the tyres. Wheel alignment crucially affects the driving characteristics in bends.
Here the distinction is made between
•
Under-steering
•
Over-steering
•
Neutral steering
Wheelbase
The wheelbase is measured from the centre of the front axle to the centre of the rear axle. In the
case of multi-axle vehicles, the individual wheelbases are given consecutively from front to rear. A
long wheelbase gives greater cargo space, more driving comfort and a reduced tendency to pitching
movements. A short wheelbase facilitates the handling of tight bends.
Total toe
The total toe is the dimension between the centre-line of the tyres. In the case of twin-wheel axles,
the measurement is taken from centre-line to centre-line of the twin wheels. This has a crucial effect
on the steering characteristics of the vehicle in bends. An uncorrected toe enables higher speeds in
bends.
Under-steering
Over-steering