Automobile Tyres
Automobile Tyres
ContentsTyre-functions & Properties.Tyre-Types Types of carcass(Tread)Comparison of radial & bias-ply
tyresTyre materials & Considerations in
tread designTyre designation & Factors affecting
tyre lifeTyre trouble shooting & Tyre
manufacturing
Tyre and its functionsTyre 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.
Tyre cross-section
Functions of tyreTo 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.
Properties of tyresNon-skiddingUniform wearLoad-carryingCushioning Power consumptionTyre noiseBalancing
Types of tyresConventional tubed tyre.
Tubeless tyre.
Tubed tyre
Tubeless tyre
Advantages of tubeless tyres
Lesser unsprung weight.Better cooling.Lesser rolling resistance.Comfortable ride.Slower leakage of air.Simpler assembly.Improved safety.
Types of carcass(Tread)
Cross ply (or) bias ply type.Radial ply type.Belted bias ply type.
Cross ply (or) bias ply type.
Cross ply (or) bias ply type.
Radial ply type
Radial ply type.
Belted bias ply type
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.
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.
Tyre materialsFor 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.
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.
Considerations in tread design
Grip
Noise
wear
Tyre designation
Factors affecting tyre life
Inflation
Vehicle maintenance
Manner of driving
Miscellaneous factors
Tyre trouble shootingSide wear of tyresOne side wear of tyresCentre wear of tyre treadUneven tyre wearUniform rapid wearRapid wear with feathered edges on
the treadTread crackingTread or ply separationLoss of tyre pressureRadial tyre leadRadial tyre waddle
Tyre manufacturing
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