Wheels and Tyres Wheels and Tyres

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The pneumatic tyre was The pneumatic tyre was developed back in 1888 by J.B. developed back in 1888 by J.B. Dunlop for use on bicycles but Dunlop for use on bicycles but was quickly adapted for use on was quickly adapted for use on

motor vehicles. motor vehicles.

Tyres form the first part of the Tyres form the first part of the vehicle’s suspension as the vehicle’s suspension as the vehicle is suspended on a vehicle is suspended on a

cushion of air which helps to cushion of air which helps to absorb road shocks.absorb road shocks.

Early tyres used a separate Early tyres used a separate inner tube but nowadays it is inner tube but nowadays it is more common for tyres to be more common for tyres to be

tubeless. tubeless.

Name advantages gained from Name advantages gained from using tubeless tyres:using tubeless tyres:

• Better ability to seal air i.e. pressure is maintained better in tubeless tyres

• The soft inner rubber liner makes the tubeless tyre self seal when punctured

Tyres must be constructed to Tyres must be constructed to perform several tasks, list below perform several tasks, list below tasks performed by the vehicle’s tasks performed by the vehicle’s

tyres:tyres:• Support the weight of the vehicle• Provide adhesion to the road in a variety

of conditions i.e. wet, dry or icy • Provide minimal rolling resistance • Transmit drive to the road• Absorb shock

There are two main types of tyre, There are two main types of tyre, these are known as what?these are known as what?

• Radial ply tyres

• Cross ply tyres

Label the radial tyre:Label the radial tyre:

Rubber sidewall

Plies Inner lining

Bead wires

Bead filler

Tread bracing layers

Tread pattern

Cross ply tyreCross ply tyre

Tyre sidewall

Casing plies

Bead wires

Inner tyre

Tread pattern

Questions Questions 1. Which of the two tyre types has the plies which

run at approximately 40 degrees to the tyre bead?

2. Which of the two tyres has a stiffer sidewall?

3. Which of the two tyres has the best road holding characteristics and why?

4. Which tyre has a tendency to run at higher temperatures?

5. What is the angle of the plies in relation to the bead on a radial ply tyre?

Answers Answers

1. Cross ply tyres 2. Cross ply generally have stiffer sidewall3. Radial hold the road better when

cornering as the sidewall is more flexible, this allows the tread to retain contact with the road surface

4. Cross ply tyre usually run hotter due to inter ply friction

5. Radial tyres have plies which run at 90 degrees to the bead