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CHASSIS SUSPENSION
WHEEL ALIGNMENT
6-29
A
B
c
Fig u re
6
-3 5 - Location
of Static
Balancing Weights
Where weights are assembled to only one
flange
of wheel rim they should always be as
-
semb led to
inside
flange.
When more than 3
ounces
of
weight is used, div
ide
the weight
equally
between inside and outside flanges in
order t
o maintain
dynamic balance.
See figure
6-35,
view
D.
In some cases wheel and tire
balance does
not always over come wheel balance complaints
because the brake drums themselves are out
of
balance. Balancing
drums with wheels and
tires as an
assembly is
not alwa ys
satisfactory
because
the
balance is
destroyed when
wheels
and
t
ires a
r e removed or
interchanged.
On cars
wher e trouble
is
experienced
in maintaining
proper
wheel balance, it is suggested
that
all
dr ums
be
in
dividually
checked for static
bal-
ance and corr ect ed, if necessary, as
described
under
Brake
Drum Balance
(par.
8-17)
.
Nearly
a
ll
cases of
off-balance
can be cor-
r
ected by
balancing staticall y.
If the trouble
still persists
after the complete r
otating
assem-
bly
has
been
balanced
statica lly
(balance when
the wheel
assembly is at rest
) , then t
he assem-
bly
must be checked for
dynamic balance.
b. Dynamic Balancing
Dynamic
balancing of a wheel and tire
assem-
bly must
be don
e on a machine designed to indi-
cate
out of balance
condit ions while the wheel
is
rotating. Since
procedu r es differ with
differ-
ent machines, the
instructions
of the
equipment
manufact urer
must be
carefully followed.
6-29 FRONT WHEEL ALIGNMENT
FACTORS
Wheel
alignment
is the mechanics of prop-
erly
adjusting all the factors affecting the posi-
tion of front wheels so as to cause the car to
steer with the least effort and to reduce tire
wear to a minimum.
./'
Correct alignment of the frame is essential
to proper alignment of front and rear
wheels.
Briefly, the essentials are that the frame must
be square in plain view within specified limits,
that the top and bottom surfaces of front cross
member must be parallel fore and aft, and the
bolt holes for front shock absorbers and lower
control arm shafts must be of correct size and
location.
Checking frame alignment is covered
in paragraph 9-2.
It should also be understood that wheel and
tire balance has an important effect on steer-
ing and tire
wear.
If wheels and tires are out
of balance, "shimmy" or "tramp" may develop
or tires may wear unevenly, and give the erro-
neous impression that the wheels are not in
proper
alignment. For this reason, the wheel
and
tire as
semblies should be known to be in
_pro per balance before assuming
that
wheels
are out of
alignment.
Six
factors must be considered in determin-
ing correct alignment of front and rear wheels.
These are as follows
:
a. Fron
t W
heel Caster
Caster
is the for e
and aft angle or tilt of the
king pi
n
with refere nce to a lin
e
at right angle
to
r
oad. See
figure
6-36. When
top
end of king
pin
tilts
r
earwa rd the caster is posit ive ; when
top
end of king
pin
tilts forward
the
caster is
negative.
b.
Front
Wheel
Camber
Camber is
t
he outwa r d or inward angle or
t
ilt
of
the wheels from centerline of
car,
with
reference t
o a
line
at right angle to
road.
See
figure
6-36. When to
p of wheel tilts outward
t
he camber is
positive ;
when top
of
wheel tilts
inward
t
he camber is n
egative
or
reverse.
c. King
Pin
Inclina t ion
King pin inclinat ion is the inward angle or
tilt of the king pin towards centerline of car,
with reference to a line at right angle to
road.
See figure
6-36.
d. Front Wheel Toe-In
Toe-in is the setting of the front
wheels so
that the distance
between them is less at the
front
than at
the
rear,
when wheels are in
sraight ahead position.
See figure
6-36.
e. Steering Geometry (Turning Angles)
Steering geometry is the mechanics of keep-
ing the front wheels in proper relation to each
other when making right or left turns. As the
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