Compass 2WD L4-2.0L (2009)
Toe-out on turns (1), sometimes referred to as Ackerman Steering, is the relative positioning of the front wheels while steering through a turn. This
compensates for each front wheel's turning radius. As the vehicle encounters a turn, the outboard wheel must travel in a larger radius circle than the
inboard wheel. The steering system is designed to make each wheel follow its particular radius circle. To accomplish this, the front wheels must
progressively toe outward as the steering is turned from center. This eliminates tire scrubbing and undue tire wear when steering a vehicle through a turn.
DYNAMIC TOE PATTERN
Dynamic toe pattern is the inward and outward toe movement of the front and rear tires through the suspension's jounce and rebound travel. As the
vehicle's suspension moves up and down, the toe pattern varies. Toe pattern is critical in controlling the directional stability of the vehicle while in
motion. Front and rear dynamic toe pattern is preset by the factory at the time the vehicle is assembled.
It is not necessary to check or adjust front or rear dynamic toe pattern when doing a normal wheel alignment. The only time dynamic toe pattern needs to
be checked or adjusted is if the frame of the vehicle has been damaged.
STEERING AXIS INCLINATION (S.A.I.)
Steering axis inclination (1) is the angle between a true vertical line starting at the center of the tire at the road contact point and a line drawn through the
center of the upper ball joint (or strut) and the lower ball joint. S.A.I. is built into the vehicle and is not an adjustable angle. If S.A.I. is not within
specifications, a bent or damaged suspension component may be the cause.
INCLUDED ANGLE (I.A.)
Included angle (3) is the sum of the S.A.I. angle (1) plus or minus the camber angle (2), depending on whether or not the wheel has positive or negative
camber. If camber is positive, add the camber angle to the S.A.I angle. If camber is negative, subtract the camber angle from the S.A.I. angle. Included
angle is not adjustable, but can be used to diagnose a frame misalignment or bent suspension component (spindle, strut).
THRUST ANGLE