Wheels and tyres

Pages 8 and 9

Objectives All of you will:• Identify, name and label components associated with

tyre pressure monitoring, hub bearings and run flat tyres

Most of you will: • Explain the operation of components associated with

tyre pressure monitoring, hub bearings and run flat tyres

Some of you will:• Predict symptoms of worn or damaged components

associated with tyre pressure monitoring, hub bearings and run flat tyres

Tyre pressure monitoring systems (TPMS)

There are two main types of TPM systems in use today, one system

uses the ABS system and the other uses a series of sensors fitted to the inside of the tyre rim and a

receiver unit nearby.

Describe with the aid of a drawing how the ABS operated TPM

system works:

• As the ABS system monitors wheel speeds if the speeds are different the ECU can recognise that the wheel circumference is smaller – signifying a flat tyre

What should be observed when working with the system shown below?

• This is called ‘direct tyre pressure monitoring’

• Direct tyre pressure monitors have sensors fitted to the inside of the wheel rims (part of the valve).

• They can be easily damaged when replacing tyres

There are two main types of run flat tyres.

State the difference between the two main types:

• One type is known as a self supporting run flat. This type has a thicker sidewall to enable the strength to support the weight of the vehicle in the event of a puncture.

• The other type is an auxiliary supported run flat tyre. They use an additional support ring inside special wheel rims.

Some manufacturers supply a space saver tyre instead of a full size spare today, why are space

savers used?• To save space in the boot, especially if the

‘real’ wheels are wide. • They would probably save the manufacturer

money too.

What needs to be observed when using a space saver tyre?

• There are speed and distance restrictions placed on the space savers.

• i.e. how far and how fast you can drive

It is common for a hub to be supported by two hub bearings, an

inner and an outer.

Name the different types of bearing than are in use:

• Ball bearings • Double ball bearings • Roller bearings • Taper roller bearings • Double taper roller bearings

Label the bearings:

• Double ball bearing

Taper roller bearing

• Roller bearing (parallel roller)

• Double taper roller bearing

What is the difference between a plain bearing and a roller bearing?

Roller

• A bearing that uses cylindrical rollers in between the inner and outer race

Plain bearing

• A plain bearing has no rolling components. The load can be spread over a broad area which means great loads can be supported.

This is a plain bearing

What is the difference between axial and radial loads?

Radial loading

• It is load applied to a bearing or shaft at 90 degrees to the bearing or shaft

Axial loading

• Axial loading is load applied to a bearing along its axis.

How is a hub bearing checked for wear?

• The weight is removed from the bearing• The bearing is checked for wear both radially

and axially by manipulating the hub and feeling for play.

• Play can be measured using a DTI• Road test and listen for noise when cornering

Objectives All of you will:• Identify, name and label components associated with

tyre pressure monitoring, hub bearings and run flat tyres

Most of you will: • Explain the operation of components associated with

tyre pressure monitoring, hub bearings and run flat tyres

Some of you will:• Predict symptoms of worn or damaged components

associated with tyre pressure monitoring, hub bearings and run flat tyres