2. Contents
Tyre-functions & Properties.
Tyre-Types
Types of carcass(Tread)
Comparison of radial & bias-ply tyres
Tyre materials & Considerations in tread
design
Tyre designation & Factors affecting tyre
life
Tyre trouble shooting & Tyre
manufacturing
3. Tyre and its functions
Tyre is a rubber member which gives
the cushion to the automobile. It
consists of outer cover i.e. tyre proper
and tube inside.
The tyre-tube assembly is mounted over
the wheel rim and air inside the tube
carries entire load and provides
cushion.
5. Functions of tyre
To support the vehicle load.
To provide cushion against the
shocks.
To transmit driving and braking
forces to the road.
To provide cornering power for
smooth steering.
18. Comparison of radial and bias-ply
tyres
Advantages of radial ply tyres:-
The side walls can be bend readily ,its shock
absorbing capacity is 25% more than bias
ply or cross ply.
The breaker strips of radial tyres act
independently of the wall plies unlike in
cross ply where there is no breaker strip.
Lower rolling resistance and hysteresis loss
leads to less fuel consumption.
19. Longer tread life because of less heat build
in tyre.
Breaking efficiency on wet roads is better
because of greater sidewall flexibility and
tread stiffness.
Smaller slip angles and higher cornering
power which results in Better steering
characteristics.
While taking turns it has less tendency to
distort and lift off the road from one side.
Larger resistance to punctures ,cuts and
impacts in the tread area.
20. Tyre materials
For carcass:-
At the time of second world war, staple cotton
was the tyre carcass material and it was
replaced with rayon.
Then nylon was introduced which is stronger,
more elastic and cooler running than rayon.
Then terylene was introduced.
21. For cords of stabilizer belts:-
Rayon ,Terylene ,glass fibre or steel.
Rubber :-
Rubber used in tyres is blend of natural and
synthetic rubbers to which various
chemicals are added to obtain desired
properties like wear resistance ,reduced
hysteresis, less internal friction.
25. Factors affecting tyre life
Inflation
Vehicle maintenance
Manner of driving
Miscellaneous factors
26. Tyre trouble shooting
Side wear of tyres
One side wear of tyres
Centre wear of tyre tread
Uneven tyre wear
Uniform rapid wear
Rapid wear with feathered edges on the tread
Tread cracking
Tread or ply separation
Loss of tyre pressure
Radial tyre lead
Radial tyre waddle
