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Camber is the amount in inches or degrees that the front wheels are tilted outward at the top.
CAMBER ANGLE
When a wheel has too much camber, that is the wheel is tilted
too far out at the top, the tire is forced by road contact into
a conical shape, on its under side. The result would be excessive
tire wear on the outer edges of the tread.
Reverse camber, or a wheel that is tilted too
far in at the top, would result in excessive tire wear on the
inner edges of the tread. The center of the tread would remain
comparatively unworn.
The rule is that if wheels have the maximum of allowable camber
they must have the maximum amount of allowable toe-in. If wheels
have the minimum amount of allowable camber they must have the
minimum amount of allowable toe-in.
King Pin Inclination
King pin inclination is the amount in degrees that the tops of
the king pins are inclined toward the center of the car. See
Fig. 203.
Fig. 203— King Pin Inclination
King pin inclination tends to keep the wheel spindles pointed
outward, in line with the axle, just as caster tends to keep the
wheels of an auto-mobile pointed straight ahead. The effect is
the same, since if the spindles are kept pointing out at right
angles of the car, the wheels will, as a result, be kept pointing
ahead. It makes the car steer easier.
We have already referred to the close relation-ship between the
factors that enter into the front axle assembly. It is a point
that cannot be over-stressed. One must keep this close inter-relation
constantly in mind to gain a full and true under-standing of this
cleverly designed mechanism. And especially in order to correct
any wrong adjustment, it is necessary to realize what effect a
change in one element of the mechanism may have on the operation
of the other parts.
Toe-In
Toe-in is the amount in inches that the wheels toe-in,
that is the distance between the front wheels at the front, "A," is
less at the front than it is at the rear "B." See Fig.
204.
Fig. 204— Toe-In
Cambering the wheels out at the top makes it necessary to draw
them in at the front.
Toe-in is a necessity growing out of camber and directly related
to it. It might seem that since the wheels are headed inward toward
the center of the road, while actually traveling a parallel course,
there must be a constant grinding of their surfaces on the road
surface. It would appear that they are being held apart constantly
by the axle, against their tendency to roll outward to the same
point. As a matter of fact, it is to avoid this tire-wearing surface
grind that toe-in is employed.
Just as the purpose of camber is to give the wheel a setting so
it will be in nearly a balanced free-running position as possible,
so with toe-in, the purpose is to set the wheel in a position to
reduce to a minimum the road friction on the tire.