Tyres
The tyre casing comprises the entire main structural body of a tyre, often called the carcass.
Cross Ply Type
As I mentioned earlier the casing forms the framework and it consists of layers called plies. In a cross ply tyre the plies are arranged in 30-40 degrees to each other. This arrangement makes the tyre resistant to stress and protects it from sudden acceleration, cornering and braking.
The angle of plies may vary according to the application and usage factors. The steering ability of the vehicles can be increased by using these type of tyres with higher cord angles. Reduced angle cords are well suited for high speeds and racing.
CONSTRUCTION
- Simple
- Easy to repair
FOOTPRINT
- Round Shape
- Uneven pressure distribution
- High soil compaction
PERFORMANCE
- Flexible
Radial Ply Type
A radial ply tyre has the ply arrangements 90 degree to each other.The radial tyre provides better handling at higher speeds while cruising through highways.
CONSTRUCTION
- Sophisticated
FOOTPRINT
- Square shape
- Even pressure distribution
- Less soil penetration
PERFORMANCE
- Superior traction
- Good stability
- Puncture resistant
- Low rolling resistance
- High mileage
- Good comfort
- Durable
- Even wear
Tread
A tread can be often seen outside a tyre as grip. It is a rubber layer which protects the casing. The tread is the layer which has contact with road surface. Different type of tread designs are used according to the type of application. It provides minimum resistance, minimum noise, no skidding and better stability.
The no tread pattern provides more contact surface area between the tyre and track where a good grip and traction is necessary during high speeds. Apart from racing these tyres cannot be used in everyday applications since it wont provide better grip on wet surfaces. So tyre manufacturers combine a blend of real world applications to create a tread pattern.
A dirt bike used in moto cross uses large knobby button type tread design to provide better grip in off roads, hilly and muddy terrains.
the sidewall also absorbs road shocks and protect the cord plies.
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Types of tyres
-Conventional Tube Tyre
-Tubeless Tyre
Tube Tyre
Tubeless Tyre
Airless Tyres
Airless tyres are the latest tyres and also a great technological breakthrough. The Airless tyres do not employ any compressed air. Leading tyre manufacturers like Bridgestone and Michelin have experimentaly developed these airless tyres. Bridgestone's Green Airless eco-tyres and Michelin's Tweel an experimental tyre design is all set to be launched soon.
The Tweel From Michelin
The Tweel consists of a cable-reinforced band of conventional tire rubber with molded tread, a shear band just below the tread that creates a compliant contact patch, and a series of energy-absorbing polyurethane spokes. The rectangular spokes can be designed to have a range of stiffness, so the load handling can be controlled. The inner hub contains a matrix of deformable plastic structures that flex under load and return to their original shape. The tread can be as specialized as any of today's tyres and can be replaced when worn.
The Tweel does have several drawbacks, the worst being vibration. Above 50 mph (80 km/h), the Tweel vibrates considerably. It also causes two other things: noise and heat. A fast moving Tweel is unpleasantly loud. Also, long-distance driving at high speeds generates more heat which might lead to premature failure. The Tweel can also withstand a police 'stinger' spike strip, which would force law enforcement to adapt in order to catch a suspect in a vehicle equipped with Tweels.
Bridgestone's Airless Tyres
Whatever a motorcycle or a car, whether it is a Mercedes or a Nano, without proper tyres we cannot ride. The traction between the road and the vehicle is made only by tyres. Many may think a tyre is just a round piece of rubber, but many don't know the engineering and technology behind the manufacturing of tyres. The tyres serve two important purposes for the vehicle, one they absorb the shock created by the irregularities of the road which in turn gives a comfortable ride to a rider and two, a good tyre provides good traction ie, a good road grip between the road and the vehicle which enables to accelerate, brake, make turns without skidding.
A poor tyre design affects the overall performance of the automobile. Some of the drawbacks include poor delivery of engine power, poor handling, less grip, poor braking and cornering. These things can be overcome by better engineering of tyres and designs.
The manufacturing of tyres is similar to the construction of a building. It has different frameworks and designs.
The three major frameworks involved in the manufacturing of tyre are,
- Casing
- Tread
- Side walls
Casing
The tyre casing comprises the entire main structural body of a tyre, often called the carcass.
The framework for the manufacture of tyre lies in its casing. This construction enables a tyre to hold air at higher pressures and provides strength. The tyre casing is an inner structure of the tyre
reinforced in manufacturing process, with the layers of rubber
one above the other. This arrangement is called as ply or plies. The plies are made of polyester, nylon, rayon, or steel, that comprise
the resistant structure of the tyre upon which the tread, belts, bead,
and sidewall are laid. This ply number differs according to different tyres. This is called as ply rating.
for example a truck tyre may have upto 22 plies and an earth moving equipment may have 34 plies. Depending on the arrangement type of these plies the tyres are broadly classified into
- Cross ply tyre
- Radial ply tyre
Cross Ply Type
As I mentioned earlier the casing forms the framework and it consists of layers called plies. In a cross ply tyre the plies are arranged in 30-40 degrees to each other. This arrangement makes the tyre resistant to stress and protects it from sudden acceleration, cornering and braking.
lower cord angles are better for high speeds and higher cord angle provide greater strength to the tyre. The reinforcing cords extend
diagonally across the tyre as shown from bead to bead at an angle of 30 to 40
degrees to the centre line of the tyre. Each successive ply or layer of
body cord runs in the opposite direction which results in a crisscross
pattern.
CONSTRUCTION
- Simple
- Easy to repair
FOOTPRINT
- Round Shape
- Uneven pressure distribution
- High soil compaction
PERFORMANCE
- Flexible
Radial Ply Type
A radial ply tyre has the ply arrangements 90 degree to each other.The radial tyre provides better handling at higher speeds while cruising through highways.
The plies of reinforcing tyre cord extend from bead to bead at a 90
degree angle to the centreline of the tyre as shown above. Directly on top of the
radial plies and under the tread is a full length belt made up of
several plies of cord or steel. The cords are placed in the belt at a low angle of 15 to 25
degrees.
CONSTRUCTION
- Sophisticated
FOOTPRINT
- Square shape
- Even pressure distribution
- Less soil penetration
PERFORMANCE
- Superior traction
- Good stability
- Puncture resistant
- Low rolling resistance
- High mileage
- Good comfort
- Durable
- Even wear
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| The Difference |
Tread
A tread can be often seen outside a tyre as grip. It is a rubber layer which protects the casing. The tread is the layer which has contact with road surface. Different type of tread designs are used according to the type of application. It provides minimum resistance, minimum noise, no skidding and better stability.
All the driving forces, handling, braking and cornering depends on the tread design. The tread design pattern differs to its application. Racing bikes and cars use racing slick tyres during race. These tyres do not have any tread design or pattern.
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| A Racing Slick used in Motorcycle |
The no tread pattern provides more contact surface area between the tyre and track where a good grip and traction is necessary during high speeds. Apart from racing these tyres cannot be used in everyday applications since it wont provide better grip on wet surfaces. So tyre manufacturers combine a blend of real world applications to create a tread pattern.
A dirt bike used in moto cross uses large knobby button type tread design to provide better grip in off roads, hilly and muddy terrains.
Sidewalls
Sidewalls are the rubber walls present at the sides of a tyre. The sidewalls are used to provide support and are used to print the tyre information, size, manufacturers name.
the sidewall also absorbs road shocks and protect the cord plies.
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| Reading The Tyre Information. |
Types of tyres
-Conventional Tube Tyre
-Tubeless Tyre
Tube Tyre
Everyone is familiar about a tube tyre. The tube tyre consists of tube and tyre in a seperate fashion -the tube is placed inside the tyre. The tube is inflated by using compressed air. The air inside acts as cushioning medium and allows the tyre to roll freely. This tyre cannot run if it gets flat. It gets instantly flat when punctured, the air under pressure finds a way between the tube and the tyre. Now special type of tubes and self-sealing tubes are available to minimize the danger of punctures or blowouts.
Tubeless Tyre
A tubeless tyre is of latest type which do not have a tube and a tyre seperate, instead the inner tube is integral within the tyre. The valve is permanently fixed to the rim. This assembly is airtight. Tubeless tyre is lighter in weight. It runs cooler than the tubed tyre and provides better control of the vehicle. It do not loses air quick when it gets punctured and it can be corrected easily without removing the tyre from wheel. This type is simple and facilitates improved safety and performance.
Airless Tyres
Airless tyres are the latest tyres and also a great technological breakthrough. The Airless tyres do not employ any compressed air. Leading tyre manufacturers like Bridgestone and Michelin have experimentaly developed these airless tyres. Bridgestone's Green Airless eco-tyres and Michelin's Tweel an experimental tyre design is all set to be launched soon.
 |
| Bridgestone's Airless Tyre Concept |
The Tweel From Michelin
Tweel Design
The Tweel consists of a cable-reinforced band of conventional tire rubber with molded tread, a shear band just below the tread that creates a compliant contact patch, and a series of energy-absorbing polyurethane spokes. The rectangular spokes can be designed to have a range of stiffness, so the load handling can be controlled. The inner hub contains a matrix of deformable plastic structures that flex under load and return to their original shape. The tread can be as specialized as any of today's tyres and can be replaced when worn.
Benefits and drawbacks
These tyres do not get flat when it gets punctured so no need to worry of getting flat tyres. Also, the concept has the
potential for true performance gains. It can be able to
outperform conventional tires since it can be designed to have high
lateral strength (for better handling) without a loss in comfort.
The tread around the circumference can be disposed of
when worn as without replacing whole tyre.
The Tweel does have several drawbacks, the worst being vibration. Above 50 mph (80 km/h), the Tweel vibrates considerably. It also causes two other things: noise and heat. A fast moving Tweel is unpleasantly loud. Also, long-distance driving at high speeds generates more heat which might lead to premature failure. The Tweel can also withstand a police 'stinger' spike strip, which would force law enforcement to adapt in order to catch a suspect in a vehicle equipped with Tweels.
Bridgestone's Airless Tyres