Suspension Construction

Suspension Construction

Auto Theory

During this lesson...

• We will discover the main part of the suspension system
• Discuss different types of suspension systems
• Be able to differentiate between different suspension parts.

Review from last meeting...

• Frame

• Shock Absorber

• Spring

• Control Arm

• Control Arm Bushing

• Ball Joint

• Steering Knuckle

Suspension System Construction

• Now that we have seen the parts lets look at them with more detail.

Control Arms

• Holds the steering knuckle, bearing support, or axle housing in position as the wheel moves up and down.

• One end is connected to the steering knuckle via Ball Joint, and the other end is connected to the Frame via Control Arm Bushings.

Multiple Choice

What is the purpose the Control Arm Bushings between the frame and control arm?

• To act as a bearing allowing the arm to pivot up and down

• To increase road noise and vibrations

• To add a little more suspension to the system

• To allow the steering knuckle to pivot

Control Arm Bushings

• 2 Per Control Arm
• Act as a bearing/pivot point for the control arm
• Stiffness can be changed to change driving feel

The ball joint connects the control arm to the steering knuckle.

Poll

Why are ball joints typically found only on the front suspension system?

• Ball Joints are needed to allow the front wheels to turn

• To save cost

• Ball Joints are a pivot between the frame and control arm

• Ball joints can be found on the rear suspension system if the car has 4 wheel steering.

Ball Joints

• Short for Ball and Socket Joint

• Contected the control arm to allow for limted rotation off the steering knuckle.

The ball joint is very similar to our shoulder joints

Steering Knuckle

• Found on the front suspension system

• Connection point for brakes, wheel bearing, tie rods, control arms, and struts

• We will go into more detail on the knuckle later and in steering systems

Here is a custom suspension system with all the parts connected.

Multiple Choice

Having a control arm in the suspension systems makes it a _____________.

• Dependent Suspension System

• Independent Suspension System

Shock Absorbers

• Shock Absorbers are connected to each wheel

• They are used to limit the ocsicallations from the spring to smooth the ride.

Why we need shock absorbers.

Multiple Choice

Which of the following would best describe the ride of a vehicle with no or worn shock absorbers?

• Bouncy

• Stiff

• Rigid

• Soft

Here you can see the good shock absorb the spring occilations keeping the wheel steadier

How a shock absorber works...

• Gas pressurized fluid is transferred inside of tube

• Fluid movement is controlled in the shock to slow the movement of the spring

• Shocks can get very complex and there are several differant types

Shock absorber!

A strut is structural to the suspension system and contains the shock and spring.

Multiple Choice

Besides poor ride quality what do you think would be a sign of a worn shock?

• Leaking Fluid

• More road noise

• Alignment change

• Stiffer ride quality

The Stabilizer Bar (Sway Bar)

Multiple Choice

Which of the following body movements does the Stabilizer Bar (Sway Bar) try to prevent?

• Body Dive

• Body Roll (Sway)

• Body Squat

Stabilizer Bar (Sway Bar)

• Connects to both lower control arms and to the frame.

• Rubber bushings connect it to the control arms. These link are called Sway Bar Links

Sway Bar Link Connection

To wrap up this lesson today lets look a couple front suspension system types.

• MacPherson Strut Suspension

• Short Arm Long Arm (SLA) Suspension (Double Wishbone)

• Torsion Bar Suspension

MacPherson Strut Suspension...

• Most common type of front suspension system.

• Cheap to produce. Less parts and simplicity

• Features a MacPherson Strut

• Only one Lower Control Arm

Short Arm Long Arm (SLA or Double Wishbone)

• What is the difference?

Open Ended

By looking at the last image what is the main difference between SLA and MacPherson?

SLA Suspension...

• Two control arms (Upper and Lower)

• Upper Control Arm Shorter

• Lower Control Arm Longer (SLA)

• Has better geometry compared to MacPherson

• Keeps the wheel straight during compression and rebound.

F1 Suspension

Torsion Bar Suspension

• Very Similar to SLA

• Uses a Torsion Bar instead of coil spring

Torsion Bar Suspension

Use the rest of this time to make up missing work.