Steering Angles & Alignment

Question 1

What is steering stability?

Answer 1

The vehicles tendency to want to go straight, term is synonymous with predictable directional control

Question 2

What steering angle are to be considered when preforming a alignment?

Answer 2

Toe
Caster
Camber 
King pin inclination
Turning radius
Thrust and scrub

Question 3

Angle primary purpose classifications

Answer 3

Tire wearing

Directional control

Question 4

What are the primary tire wearing angles?

Answer 4

Toe
Camber
Turning radius

Question 5

What are the 3 major characteristics to focus on when doing a alignment?

Answer 5

Ease of steering
Steering stability
Reduced tire wear

Question 6

Caster

Answer 6

Is the forward or backward tilt of the king pin at the top (viewed from the side)

Question 7

Purpose of castor

Answer 7

Tends to increase the vehicles tendency to want to go straight

Question 8

Positive castor

Answer 8

Tilting the steering axis rearward. load is projected ahead of the tire point of contact. Wants to hold straight ahead more

Question 9

Excessive positive castor

Answer 9

Can cause excessive road shock, heavy steering and shimmy

Question 10

Castor pull

Answer 10

The vehicle will want to pull to the side with the least positive castor

Question 11

Excessive negative castor

Answer 11

Causes easier steering at low speeds, but instability at high speeds, combined with wander and weave

Question 12

Camber

Answer 12

The outward or inward tilt of the wheel at the top (viewed from the front)

Question 13

Positive camber

Answer 13

Tilts outward

Question 14

Negative camber

Answer 14

Tilts inward

Question 15

Purposes of camber (2)

Answer 15

Brings the point of contact more directly under the point of the load
Provides easy steering by allowing the weight of the vehicle to be carried closer to the steering axis

Question 16

Camber pull

Answer 16

Vehicle will pull to the side with the most positive camber

Question 17

Kingpin Inclination Angle (KPI)

Answer 17

The inward tilt of the steering axis at the top.

Question 18

Purpose of KPI

Answer 18

It reduces the need for high camber
it brings the point of contact more directly under the point of load
Reduces road shock and brake pull
Provides steering stability

Question 19

Included angle

Answer 19

Angle when camber and KPI are added together

Question 20

Scrub radius

Answer 20

The distance between the projected steering axis and the centre of the tire contact area, measured at road surface.
Most vehicle’s have positive scrub (projected KPI is inside of contact area)

Question 21

Turning radius

Answer 21

Toe out on turns

Question 22

Ackerman Principle

Answer 22

The theoretical lines through the kingpin, tie rod end, and centre of the drive wheel assembly

Question 23

Thrust angle

Answer 23

The angle formed by the thrust line and the geometric centre line

Question 24

Geometric centerline

Answer 24

A line determined by the midpoints of the front and rear wheels.

Question 25

Vehicle centerline

Answer 25

An invisible reference line that runs longitudinally down the middle of the vehicle

Question 26

Thrust line

Answer 26

Determined by the total toe of the rear wheels. The thrust line divides the toe in half and runs up the centre of the vehicle. Determines the direction the vehicle will travel.

Question 27

Scrub angle

Answer 27

Is the angle formed by the intersection of the horizontal lines drawn through the rear axle when the total toe an offset is zero. Caused when drive axle are not square to each other and the frame

Question 28

Positive scrub

Answer 28

The 2 axles are closet on the right. Pass side = positive PP

Question 29

Negative scrub

Answer 29

2 axles are closet on the left

Question 30

Lateral run out

Answer 30

Checked on the side of rim or tire. Will affect drivability but will not affect toe readings

Question 31

Radial run out

Answer 31

checked on the face of the tire.

Question 32

castor shims can not compensate for more then how many degrees of rotation?

Answer 32

2

Question 33

When viewed from the front of a vehicle, both upper tires appear to have positive camber. The tires are tilted:

Answer 33

Out at the top

Question 34

T/F toe out on turns alignment setting will be correct when the outer front tire turns at a sharper angle then the inner tire?

Answer 34

False | inner is sharper

Question 35

Wheel bearings that are out of adjustment (loose) may affect two particular wheel alignment settings, what are they?

Answer 35

Toe | Camber

Question 36

Suspension components that are weak and sagging due to a bent axle, may affect two alignment settings, what are they?

Answer 36

Camber | Castor

Question 37

T/F Positive caster projects the point of load ahead of the point of contact?

Answer 37

True

Question 38

How are the KPI and toe out on turns corrected if found to be out of spec on a alignment?

Answer 38

All damaged parts must be replaced and can not be repaired