Saab SONETT III Service Manual page 107

WHEEL TURNING ANGLES
If wheel alignment is correct, all four wheels will describe
circles with a common center when the car takes a curve,
and as the rear wheels are fixed this center must lie some-
where on their extended axis. As shown in the figure be-
low, the inner front wheel must be turned more than the
outer one when tak ing a curve, in order for both wheels
to move around the same center.
Correct steering geometry depends essentially on the
alignment of the steering arms, but the tie-rod alignment
also has some bearing on it, particularly when suspension
movement occurs, see fig.
Checking and adjustment
Before checking of turning angles is commenced, the toe-
in must be correctly adjusted. To measure the turning
angles, use is made of two standard-type turn-tables with
arc graduations or optical measuring equipment — see
fig. Position the turn-tables as close to the wheel turning
center as possible.
Tum n the steering wheel to, for instance, the left, until
the graduated disc for the front wheel shows a reading
of 20 0 . If the turning setting is correct, the other disc
should give a reading of 22 1/2° ± 1 1/2°.
Measure in the corresponding manner when the steering
wheel is turned in the opposite direction. If measurement
reveals that the turning angles are incorrect, one or both
steering arms is deformed. Defective steering arms must
not be restraightened but must be changed instead.
fl
TURNING ANGLES OF FRONT WHEELS
1. Turning radius
2. Wheel base
3. Track
601-5
SAAB
June 1970