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STEERING SYSTEM
589
STEERING
WHEEL ALIGNMENT
Wheel alignment is a procedure of aligning wheels
according to the specifications.
The purpose of these adjustments is to give maximum
tire life and vehicle-travel that is straight and true when
driving along a straight and level road. Acorrect wheel
alignment is necessary because it affects directional
stability, tire tread wear and vehicle’s safety.
Warning signs of improper wheel alignment include
steering wheel shimmy, a constant steering pull to
one side, tire squeal noises when making turns,
excessive vibration as speed accelerates, and
changes in direction after a car has hit a bump on the
road. If any of the above symptoms are noticed, wheel
alignment becomes necessary.
Wheel alignment should be done at the time of fitting
new tires and thereafter at regular intervals. Wheels
which may be only a fraction out of alignment can
scrub or drag along the road instead of rolling along
it.
Normally overall wheel alignment refers to the
procedures used to check and adjust the steering
system, including the camber, caster, and toe.
The purpose of toe is to ensure that the wheels roll
parallel. Toe also serves to offset the small deflections
of the wheel support system that occur when the
vehicle is rolling forward. In other words, with the
vehicle standing still and the wheels set with toe-in,
the wheels tend to roll parallel on the road when the
vehicle is moving.
Toe settings affect three major areas of
performance:
(a) Tyre wear
(b) Straight-line stability and
(c) Vehicle handling characteristics
In case of TATA NANO, ONLY TOE IN adjustment
is required.
Following precautions are to be taken before
commencing wheel alignment:
1. Car should be unladen and parked on level surface.
2. Front and rear tires should be inflated to correct
pressure (28 and 30 psi respectively)
3. Ensure that bushes in the front/rear suspension
are in satisfactory condition.
4. Ensure that front rear & suspension fasteners are
tightened to their specified torques.
5. Also ensure that there is no visible damage to any
of the suspension parts like lower link bushes and
struts.
6. Ensure that there is no play in steering linkages
and suspension ball joints.
7. Ensure no tyro wear on any wheels. If so replace
the respective tires.