Daewoo Nubira. Manual — part 258

WHEEL ALIGNMENT 2B – 11

DAEWOO V–121 BL4

GENERAL DESCRIPTION

AND SYSTEM OPERATION

FOUR WHEEL ALIGNMENT

The first responsibility of engineering is to design safe
steering and suspension systems. Each component must
be strong enough to withstand and absorb extreme pun-
ishment. Both the steering system and the front and the
rear suspensionmust function geometrically with the body
mass.

The steering and the suspension systems require that the
front wheels self–return and that the tire rolling effort and
the road friction be held to a negligible force in order to al-
low the customer to direct the vehicle with the least effort
and the most comfort.

A complete wheel alignment check should include mea-
surements of the rear toe and camber.

Four–wheel alignment assures that all four wheels will be
running in precisely the same direction.

When the vehicle is geometrically aligned, fuel economy
and tire life are at their peak, and steering and perfor-
mance are maximized.

TOE

Toe–in is the turning in of the tires, while toe–out is the
turning out of the tires from the geometric centerline or
thrust line. The toe ensures parallel rolling of the wheels.

The toe serves to offset the small deflections of the wheel
support system which occur when the vehicle is rolling for-
ward. The specified toe angle is the setting which achieves
0 degrees of toe when the vehicle is moving.

Incorrect toe–in or toe–out will cause tire wear and re-
duced fuel economy. As the individual steering and sus-
pension components wear from vehicle mileage, addition-
al toe will be needed to compensate for the wear.

Always correct the toe dimension last.

CASTER

Caster is the tilting of the uppermost point of the steering
axis either forward or backward from the vertical when
viewed from the side of the vehicle. A backward tilt is posi-
tive, and a forward tilt is negative. Caster influences direc-
tional control of the steering but does not affect tire wear.
Weak springs or overloading a vehicle will affect caster.
One wheel with more positive caster will pull toward the
center of the car. This condition will cause the car to move
or lean toward the side with the least amount of positive
caster. Caster is measured in degrees and is not adjust-
able.

CAMBER

Camber is the tilting of the top of the tire from the vertical
when viewed from the front of the vehicle. When the tires
tilt outward, the camber is positive. When the tires tilt in-
ward, the camber is negative. The camber angle is mea-
sured in degrees from the vertical. Camber influences
both directional control and tire wear.

If the vehicle has too much positive camber, the outside
shoulder of the tire will wear. If the vehicle has too much
negative camber, the inside shoulder of the tire will wear.

Camber is not adjustable.

STEERING AXIS INCLINATION

Steering Axis Inclination (SAI) is the tilt at the top of the
steering knuckle from the vertical. Measure the SAI angle
from the true vertical to a line through the center of the strut
and the lower ball joint as viewed from the front of the ve-
hicle.

SAI helps the vehicle track straight down the road and as-
sists the wheel back into the straight ahead position. SAI
on front wheel drive vehicles should be negative

INCLUDED ANGLE

The included angle is the angle measured from the cam-
ber angle to the line through the center of the strut and the
lower ball joint as viewed from the front of the vehicle.

The included angle is calculated in degrees. Most align-
ment racks will not measure the included angle directly. To
determine the included angle, subtract the negative or add
the positive camber readings to the Steering Axis Inclina-
tion (SAI).

SCRUB RADIUS

The scrub radius is the distance between true vertical and
the line through the center of the strut and lower ball joint
to the road surface. Scrub radius is built into the design of
the vehicle. Scrub radius is not adjustable.

SETBACK

The setback is the distance in which one front hub and
bearing assembly may be rearward of the other front hub
and bearing assembly. Setback is primarily caused by a
road hazard or vehicle collision.

TURNING ANGLE

The turning angle is the angle of each front wheel to the
vertical when the vehicle is making a turn.