Suspension Systems

Question 1

What are the two types of frames that are used in vehicle construction today

Answer 1

Conventional Frame Construction

Unibody Construction

Question 2

What is the basic function of the Springs?

Answer 2

absorbs shock forces while maintaining correct riding height

Question 3

What is spring rate?

Answer 3

The amount of deflection exhibited under a specific load.

The amount of load necessary to deflect the spring 25.4 mm or 1 inch

Question 4

What is jounce?

Answer 4

occurs when a wheel hits a bump and moves up.

Question 5

What is rebound?

Answer 5

Occurs when a wheel hits a dip or hole and moves downward

Question 6

What is the role of the shock absorber?

Answer 6

to dampen and stop the motion of the spring after jounce

Question 7

What is sprung weight?

Answer 7

the vehicle’s weight supported by the suspension system. Ex. body, frame, engine, transmission, etc…

Question 8

What is unsprung weight?

Answer 8

the weight of the components not supported by the springs. Ex. steering knuckles, rear axle assemblies, etc…

Question 9

What are linear rate coil springs?

Answer 9

coil springs that have one basic shape and a consistent wire diameter.

Question 10

What are variable rate coil springs?

Answer 10

Coil springs that are characterized by a combination of wire sizes and shapes.

Question 11

What are cargo coils?

Answer 11

variable rate springs with a consistent wire diameter and unequally spaced coils.

Question 12

How do consistent wire diameter progressive rate coils work?

Answer 12

At stationary loads, the inactive coils are supporting all the vehicle’s weight. As the load increases, the transitional coils take over until they reach maximum capacity. Finally the active coils carry the remaining overload. - Allows for automatic load adjustment while maintaining vehicle height.

Question 13

How do variable wire diameter progressive rate coils work?

Answer 13

The active coils have a large wire diameter and the inactive coils have a small wire diameter.

Question 14

What are the three types of leaf springs?

Answer 14

multiple leaf
monoleaf
fibre composite

Question 15

What are the characteristics of multiple leaf springs?

Answer 15

• Flat steel leaves that are bundled together and held together with clips or a bolt.
• The farther the spring deflects, the stiffer it gets.
• The more leaves, the stronger the spring
• The thicker and shorter the leaves, the stronger the spring
• The ends of the leaves slide over one another as the spring flexes creating friction and noise.

Question 16

What are the characteristics of Monoleaf springs?

Answer 16

• Usually have a heavy or thick centre section that tapers off at both ends.
• Provides a variable spring rate and a smooth ride
• Does not produce noise or friction

Question 17

What are the characteristics of Fibre Composite springs?

Answer 17

• Incredibly lightweight
• Smoother riding, better handling and faster responding suspension
• Reduces the sprung mass of the suspension which reduces the spring effort and amount of shock control required to keep the wheels in contact with the road.

Question 18

What are the characteristics of Air Springs?

Answer 18

• Uses air to provide a comfortable street ride with automatic front and rear load levelling.
• Consists of a reinforced rubber bag pressurized with air

Question 19

What are torsion bars?

Answer 19

A straight spring that twists and straightens out to absorb up and down movement. They are directional and are usually marked left and right.

Question 20

How do torsion bars work?

Answer 20

One end is attached to the frame and the other end is attached to the lower control arm. As the lower control arm moves up and down, the torsion bars twists.

Question 21

What are shock absorbers?

Answer 21

Hydraulic cartridges that dampen spring movement. They prevent uncontrollable bounce. The faster they move, the more resistance they have.

Question 22

What types of shocks are there?

Answer 22

Conventional (double-tube)
Monoshock (single tube)
Gas-charged monoshock
Manual fill air shock
Automatic load levelling air shock

Question 23

How does a shock work?

Answer 23

Under compression, the piston rod moves downward in the shock. The piston pushes on the oil in the chamber which presses on the dividing piston and compresses the gas chamber. When the shock rebounds, the gas pressure returns the dividing piston back to it’s original location. The valves in the shock control the rate of compression (jounce) and rebound

Question 24

What is shock absorber ratio?

Answer 24

The proportion of a shocks ability to resist jounce (compression) and rebound.

Indicated by percent jounce / percent rebound