Design Position of Wheel Center

Question 1

What is the Wheel Base

Answer 1

Distance in the vehicle’s xz plane between the center of tire contact at the front and rear wheels

Question 2

Wheel Contact Point

Answer 2

Intersection between the roadway and the wheel’s center plane

Question 3

Long Wheel Base Influence

Answer 3

More room for passengers
Improved ride comfort
Improved safety

Question 4

Shorter Wheel Base influence

Answer 4

Better Maneuverability
Lower Cost
Lower Weight

Question 5

Typical wheelbase values

Answer 5

2100 - 3500mm

Question 6

Ratio wheelbase to vehicle length

Answer 6

0.6 +- 0.07

Question 7

Track Width

Answer 7

The distance in the yz plane between the centers of the tires’ contact on a single axle.

Question 8

Wide track width influence

Answer 8

Better driving behaviour
Reduced vehicle roll
Improved design aesthetics

Question 9

Narrow track width Influence

Answer 9

Less stability
Increased vehicle roll
Less room for passengers and powertrain

Question 10

Track Width values

Answer 10

1210 - 1600mm

Question 11

Ratio of track width to vehicle

Answer 11

0.8 to 0.86

Question 12

Can the track width change during driving

Answer 12

Yes, camber changes and suspension kinematics effects during suspension compression and extension can change the contact path so it changes the track width

Question 13

Vehicle Center of Gravity

Answer 13

Imaginary point at which the vehicle’s entire mass can be concentrated; position varies with vehicle loading

Question 14

What does low CoG result in

Answer 14

Good handling and driving safety
Reduced vehicle pitch and roll
Reduced wheel load fluctuations on inclined surfaces

Question 15

Higher CoG results in:

Answer 15

Increased rear axle load on inclined surfaces

Question 16

Typical values of CoG

Answer 16

1000 to 1750 mm behind the front axle, 300 to 750mm above the road

Question 17

What is Wheel Travel

Answer 17

Wheel travel is the displacement
s of the center of tire contact, also
known as spring travel or
suspension travel.

Question 18

How is the wheel travel measured

Answer 18

It is measured from the neutral position.
Positive during jounce (suspension compression)
Negative during rebound (suspension extension)

Question 19

Typical values of wheel travel

Answer 19

60 to 100mm for compression
70 to 120mm for extension

Question 20

By which parameter is wheel travel described

Answer 20

1. Camber angle
2. Diagonal spring angle
3. Roll center
4. Toe change
5. Camber change

Question 21

What is Toe Angle

Answer 21

Angle in the road surface plane between the vehicle’s longitudinal axis and the center plane of the wheel

Question 22

What does the toe angle influence

Answer 22

Straightline stability, cornering behavior, and suspension tuning

Question 23

Toe out meaning

Answer 23

C > B; the distance between the front of the wheels is bigger than the distance between the back of the wheels

Question 24

Toe in meaning

Answer 24

C < B; the distance between the front of the wheels is smaller than the distance between the back of the wheels

Question 25

Typical Values of Toe angle

Answer 25

Front axle of rear-wheel-drive car 0°to +30’
Front axle of front-wheel-drive car -30’ to +20’
rear axle -20’ to +20’

Question 26

Wheel camber meaning

Answer 26

Angle between the wheel’s center plane and a plane perpendicular to the road surface including the line of intersection between the road surface and the wheel’s center plane.

Question 27

What does Camber influence?

Answer 27

Lateral dynamics, aligning torque, and suspension tuning

Question 28

Positive camber

Answer 28

The top of the wheel is further outboard than the contact
patch

Question 29

Negative Camber

Answer 29

The top of the wheel is more inward than the contact patch

Question 30

What does negative camber influence

Answer 30

It improves the wheel ability to transfer lateral forces during a curve

Question 31

Large camber angle influence

Answer 31

Increases tire wear and rolling resistance

Question 32

Why does the camber angle remain positive during straightline driving

Answer 32

To suppress steering wheel vibration but should be as small as possible

Question 33

Roll Center meaning

Answer 33

The point in the axle;s yz plane about which the vehicle body rolls

Question 34

Does the roll center point change

Answer 34

It changes during jounce and rebound

Question 35

High roll center meaning

Answer 35

Less body roll due to shorter lever arm

Question 36

Low roll center (at or below road surface)

Answer 36

Reduced camber and track width changes during jounce and rebound

Question 37

Typical roll center values

Answer 37

80 to 250mm at the rear axle
0 to 130mm at the front axle

Question 38

Steering angle

Answer 38

The angle between the vehicle’s x-axis and a line formed by the intersection of the wheel’s center plane and the road surface

Question 39

Max steer angle

Answer 39

30deg to 43deg in both directions

Question 40

Larger max steer angle?

Answer 40

Reduces vehicle’s turning radius and improves parking capabilities

Question 41

What is the steer angle limited by

Answer 41

The clearance space in the wheel wells.

Question 42

Tire/Wheel Slip Angle

Answer 42

The angle between the wheel’s velocity vector along the wheel center plane and the wheel’s actual direction of displacement at the tire contact patch.

Question 43

When does the tire slip angle occur

Answer 43

Mainly when lateral forces are acting on the center of tire contact