Alignment

Front 1

Alignment

Back 1

To make the vehicle go straight down the road and handle correctly

Front 2

Steering axis

Back 2

And imaginary line drawn between the upper and lower pivot points of the knuckle

Front 3

Caster

Back 3

The forward or rearward tilt of the steering axis as viewed from the side

Front 4

Road crown

Back 4

A hump or bow in the road

Front 5

Cross caster

Back 5

The difference in caster measurements side to side

Front 6

Returnabilty

Back 6

The tendency of the front wheels to return to the straight ahead position

Front 7

Shimmy

Back 7

a violent side to side motion of an object

Front 8

Camber

Back 8

The inward or outward tilt of the top of the wheel as viewed from the front

Front 9

Cross camber

Back 9

The difference of camber measurements side to side

Front 10

Camber roll

Back 10

The changes of camber that occur in a turn due to caster

Front 11

Total toe (linear)

Back 11

The difference in measurements taken across the front of the tires versus a measurement taken across the rear of the same tires on a given axle

Front 12

Total toe (angular)

Back 12

The angle formed by the intersections of lines drawn through both wheels of a given axle

Front 13

Individual toe (linear)

Back 13

Is the difference in distance of the front and rear of one tire In reference to the vehicle centerline

Front 14

Individual toe (angular)

Back 14

Is the angle formed by the intersection of a line drawn through one wheel in reference to the vehicle center line

Front 15

Geometric center line

Back 15

A line drawn through the midpoint of both front and rear wheels

Front 16

Thrust line

Back 16

A line bisecting the rear total toe angle, the direction the rear wheel points

Front 17

Thrust angle

Back 17

The angle formed by the intersection of the geometric centerline and the thrust line

Front 18

Dog track

Back 18

Cause by a thrust angle greater than 0

Front 19

Bump steer

Back 19

A directional change in steering during jounce and rebound due to unequal tie rod lengths or angles

Front 20

Steering axis

Back 20

A line drawn through the upper and lower pivot points of the knuckle

Front 21

Steering axis inclination (SAI)

Back 21

The angle formed by a line drawn through the upper and lower pivot points of the knuckle and a vertical line drawn from the lower pivot point as viewed from the front or rear

Front 22

Setback

Back 22

The angle formed by a line drawn perpendicular to the geometric centerline and a line connecting the center of the front wheels

Front 23

Centerline alignment

Back 23

Aligns the front wheels to the geometric centerline

Front 24

Thrust line alignment

Back 24

Aligns the front wheels to the rear thrust line

Front 25

Total 4 wheel alignment

Back 25

Aligns the rear wheels to the geometric centerline and the front wheels to the rear thrust line

Front 26

Centerline steering

Back 26

A straight and level steering wheel while driving straight down the road. + or - 3°

Front 27

Load distibution

Back 27

Refers to the weight or load placed on each wheel

Front 28

Road shock

Back 28

The transmission of road forces to the passenger compartment

Front 29

Lead or drift

Back 29

A slight tendency for a vehicle to move away from a given path

Front 30

Wander

Back 30

The tendency of a vehicle to drift to either side of a directed coarse

Front 31

Pull

Back 31

The tendency of a vehicle to steer away from a directed coarse

Front 32

Memory steer

Back 32

A condition where the front wheels seek a position other than straight ahead

Front 33

Torque steer

Back 33

A pull duringacceleration or deceleration cause by drive line components