The history of tyre dated back to the 19th century even before an automotive existed. From era where horse-drawn carriages to the latest sports car many tyre inventions were made. Some of the many notable inventors from this era were Robert Thompson, John Dunlop and Charles Welch.
The first invention was a hollow inflatable tube covered with leather by Robert Thomson in 1845. He created it to increase comfort of the passengers in the carriage. However, this invention was not a hit in the vehicle industry. The French and American released a patent to Thomson for the same invention on 1846 and 1847 respectively.
John Dunlop was a surgeon from Ireland. In 1888 he invented a pneumatic tyre. He created the tube and attached it to the rims of the tyre by tape. According to history, it was said that he did this to make his son happy as he complains that it was hard for him to ride his bicycle. Later the legendary The Dunlop Company was organised to mass produce tyres under his patent.
In 1890, The Dunlop Company adopted Charles Welch invention. He invented a form of tyre construction in which the circumference is the wheels were embedded in the edge. The wheel rim was made with a well in the centre so that it is fitting the tyre part of the wired edge. The Dunlop Company also bought over many more patents to protect their rights in America.
In a few years' time the pneumatic tyre began to arouse people's interest. The two brothers Andre and Edouard Michelin first fitted pneumatic tyres on a Peugeot racing car in 1895. This won fame to the Michelin brothers thus making Michelin Company one of the worlds renowned tyre company to this very date.
Everything must have its own structure and same goes with a tyre. A tyre is made up of several compartments which are tread, shoulder, casing (sidewall), bead, carcass, belt, and inner liner. (Refer to picture 2.1 (a) in appendix)These structures allow it to have a better traction, long lasting and also stiffer.
The main component of a tyre is the tread. A tread is built in the tyre to ensure safety as it provides a rolling resistance which can avoid slippery happens. It is made up of a broad rubber with provide friction between both the tyre and the road. Tread installed must have a lower wear rate and a better stability as this part is directly contact with the road.
Shoulder of a tyre is situated in the middle of sidewall and the tread. This shoulder is made up of rubber and it is the thickest compartment in the tyre as the purpose of it is to allow diffusion occurred. Heat produced is much easier to diffuse within the tyre when driving if it is build with a thicker rubber.
Sidewall is a structure of the tyre which is located between the bead and the shoulder. It is flexible as it protects the carcass and improves the driving condition. The speed symbols, type of tyre, aspect ratio, width section and rim diameter type, construction type and load index are carve on the tyre in a numeric and alphabetically to help in recognizing the tyre.
A bead is a part of a structure of a tyre which is connected to the rim and it is being hush-up by a cord fabric. The reason why the tyre will not fall off from the rim is because the core, bead wire and other component are comprised. In fact, it is not built in loose condition around the rim to prevent inflation pressure suddenly occurred.
Carcass in a tyre is considering a vital framework of tyre. This is because a carcass is the entire part of the inner layer in the cord fabric. A wear-resistance rubber is inserted in carcass in order to prevent it from impact which allows a driver to drive more comfortable in a long distance driving. In addition, it is also function as a shock absorber, the supporter of air pressure and vertical load.
The layers between both tread and carcass is known as the belt. It is cord in layer and the function of the belt is to protect the carcass of a bias. It is situated in between to absorb impact in order to prevent injuries. It is made up of a strong reinforcement in belted-bias tyre and radial tyre to increase the rigidity.
The inner liner is the inner part of the tyre which is constructing in layers of rubber to oppose the air diffusion in the tyre. It replaces the inner tube inside the tyre as it is made up of synthetic rubber which is commonly known as butyl to maintain the air inside the tyre. This will ensure a smoother driving and reduces the resistance between the tyre and the road.
The structure of a tyre is not design for decoration but each of the components has its own purposes and function. This entire component must combine in order to make the tyre more perfect. Therefore, each structure of the tyre determines the better traction, long lasting and also stiffness of a tyre.
2.3 Materials of tyre
In a construction of the tyre, materials are definitely important in determining the quality, suitability and other function of a tyre. Materials of a tyre can be differentiated in to a large number. In facts, materials of tyre are improving days after days to improve the tyre in all aspect. Without the improvement, the tyre will be out of date and user will eliminate it from their choices. The materials of a tyre are rubber and reinforcement fabric, composite materials, steel and textiles and oils. (Refer to picture 2.2 in Appendix)
Rubber is the most and main materials in a tyre. A tyre may consist of several types of rubbers. Usually, a car tyre is built up of halo butyl rubber in an inner linear. The ply is the next part of tyre and is made up of three layers. The first layer and second layer of ply is also rubber while the other is reinforcement fabric like nylon, Kevlar and others can be used. The rubber used must also be flexible and is able to withstand the condition of the road. This is to maintain quality of it and therefore constant changing of a tyre is not needed. A rubber which is hard is not suitable for car as the conformity is very low. Therefore, rubber and reinforcement are the two general and vital parts of materials in a tyre.
The most common material which made up of a tyre is composites materials. These kinds of composites materials are usually created because of certain improvement inside or towards the tyre. A tyre that made up of composite materials are commonly stronger which are able to withstand more resistance, stiffer, lighter as the physical of the tyre is enhanced with composite materials. Reinforcement is a quite strong material that the cluster of fibres is surrounded by the binder or matrix. In facts, tyre nowadays is made up of much kind of composite materials like steel bands, nylon belts and rayon cloth. All these are the matrix of rubber. Therefore, composite materials are good in strength to weight ratio and are the good materials for manufacturing a tyre.
Steel and textiles also are the materials of tyres. During the manufacturing of tyre, steel and textiles are made of various chemicals so it will be long lasting and stiffer. This is due to the compound combine together name alloy. Alloy is very tough as it is made up of two or more type of metals. For an example, there is a tyre company named Nokian Tyres was able to design and created an exactly eliminate high-aromatic tyre. This component of tyre is the inner part of the tyre. This will make it stiffer and were able to withstand 1.0 tan and above. If we use other component or metals like iron, the iron, a pure metal will never be a strong as the composite metals as there are spaces between particles inside iron. Therefore, the inner part of the tyre must be made of steel and textiles to enhance the stiffness of a tyre.
Oil is also important as a material of the tyre. In a rubber compound, oil in it plays an important role as plasticisers. Oil is needed in the compound because it has an impact on the traction between the tyre and the pavement. Many of the tyre company had made researches and they concluded that oils is inserted in one of the materials of tyre as it will help in reducing the rolling resistance between the tread of tyre and road. Most of the oil used by company like Nokian Tyres is vegetable oils which is safe to use. In facts, it is also low-aromatic mineral oils and consists of about 20% of it in a rubber compound.
As a conclusion, in order to produce a better quality tyre, improvement and combination of several type of material is needed. Several materials combine together will make the tyre stiffer, stronger, long-lasting and more comfortable. However, rubber and reinforcement fabric, composite materials, steel and textiles and oils are the most common and most important materials.
Tubed tyre has an inner tube acting as an elastic bag containing air that introduces air pressure into the tyre. It consists of an endless tube, a little smaller than the size of the tyre itself and a hard and thick rubber around the tube. These tubes were made with high quality natural rubber but soon it was taken over by synthetic rubber. Tubed tyres were mainly used by owners using pneumatic tyres before the creation of tubeless tyres. Tubed tyres had a downside. They can get punctured easily. When a nail pokes the tyre it punctures the tube inside losing all the air and its pressure. However tubed tyre are still used by heavy vehicles and motorbikes because tubed tyre produces mare traction. A tubed tyre
It was Frank Herzergh of the American Goodrich tyre company who perfected the tubeless that we all use today. As the name suggests, tubeless tyre is a tyre without the use of an inner tube. The tyre is fitted on to the rim such that there is air space between them. The tyre has a halo- or chloro-butyl inner coat that makes it air tight. A tubeless tyre benefits the owner as they are more economical, and safer to use.
A tubeless tyre is more economical than tubed tyre. This is because with the absence of the tube, less material and man-work are needed. In addition, a tubeless tyre has no friction between the tube and the tyre making it fuel efficient, less vibration, less heat generation and better comfort. Tubeless tyre also has lower wheel weight which produces better handling and longer tyre lifespan. ( http://www.jktyre.com/Customer_Service/Tubeless_Tyres.aspx )
A tubeless tyre is also safer than tubed tyre. When a nail punctures the tubeless tyre the air loss is not sudden. The tyre is able to carry out its function for some time before being completely flat. The tubed tyres in the other hand will lose all its air immediately. Tubeless tyre beads are designed to seat on the rim with a tight fit. In an event of loss of air, the is a lower chance for the bead to unseat.
In conclusion, a tubeless tyre has vast advantages compared to tubed tyre. This is why the tyre industry has mass produced tubeless tyre to the state that it is near impossible to find a tubed tyre on any conventional car.
A ply is a design that functions as an item that minimizes the heat built up and indirectly giving a longer life time. In facts, a ply is built up to help in better handing and maintains a better stability of the steering control. There are several types of ply in the world which is placed in a tyre which is bias-ply, belted-bias ply and radial-ply tyre.
Bias-ply or belted bias ply contain a cord that crisscross each other (Refer to picture 2.4 (a) in appendix). Bias-ply is made up of several layers of parallel cord join together transversely across the tyre between the bead to avoid the lips from slipping and stretching over the upturn flange of the rim in a tyre. The cord is design in a centreline of a tyre that starts from 25 degree to 40 degree. The tyre cord in a tyre casing is usually 50 more than the belt-ply cord angle. The most commonly use belt and ply are two plies and two belts while four plies and four belts are used inexpensively. A belted bias ply has a better tread rigidity compare to belt-ply. Its' function is to minimize the tread motion during the contact of tyre and the road and this helps in increasing the tread life of a tyre. Therefore, belted bias ply is better compare to bias-ply.
A radial ply tyre provides less compromise than the bias-ply tyre as it consists of many layer of cord which have its' own usage has a cord which is situated 90 degree to the centreline of a tyre (Refer to picture 2.4 (a) in appendix). This radial ply tyre usually uses steel belts but other materials such as nylon, rayon, Kevlar and fibreglass are also widely used. The angle between both the cord and tyre centreline are 10 to 30 degree. Usually, it uses two belts and two ply which is arranged at the alternating angles. The benefits of the radial belt ply tyres are better control of a steering, extend the life time of tread in a tyre and reduces the rolling resistance of the tyre.
As a conclusion, a bias-ply, belted-bias ply and radial-ply tyre are the main basic ply which will help in the stability and steering control. This will definitely help in minimizing the heat built up and maintain a better quality.
Tread bracing is basically related to the stiffness that gives the road a better holding and gripping between both road and tyre. Since friction occurs, it will decrease the tread and the rolling resistance will increase. Therefore, the tread of a tyre is being reduced. There is several design of tread and each of them have their own functions. The tyre tread designs are, sipe, rib shape, lug shape, rib-lug shape, block shape, Asymmetric pattern and Directional pattern.
For sipe tread, it is a fine groove (Refer to picture 2.6 (a) in appendix) which acts to increase the performance of the braking system in the same time providing conformity and driving stability. This tread is usually applied on the winter tyre as the traction on snow or icy condition will enhance the gripping and thus improve the breaking control on snowy roads and avoid slippery of tyre.
The tread for dirty road and heavy duty vehicle like buses or industrial truck uses the lug shape tread tyre. (Refer to picture 2.6 (b) in appendix) This pattern is perpendicular to the circumference of a tyre and it is the best in supporting the braking and the driving power. It also provides a better traction but it is noisy if the car is driving at a high speed because of the rolling resistance.
The tread along the circumference of the tyre is known as the rib shape tread. (Refer to picture 2.6 (b) in appendix) It will provide a better stability and steering control because of the lowering of the rolling resistance. It uses lateral resistance concept and low heat generation which is also suitable for high speed driving. However, it has a poor traction on wet pavement and it is at risk at cracking. Usually, this type of tread is use for buses or truck as they are heavier and need lower rolling resistant.
Combination of Lug-shape and Rib-shape tread is known as the Rib-Lug shape. (Refer to picture 2.6 (b) in appendix) It gives a directional control as the shoulder lug provides a better driving power and braking. The kind of tread is suitable in both pavement and the dirt road. It can also be installed whether in both front and rear tyre.
In addition, the independent block is the pattern which is connected with each other is known as the block shape tread. It is suitable for most type of tyre like all season passenger, winter tyre and also radial tyre. This tread will support steering control and stability on wet pavement and also snow covered road. It is good in water dispersal but it is very heavy in mass.
Other than that, lateral groves on each side of the tread on the tyre that point to the same direction are known as the Directional pattern tread. (Refer to picture 2.6 (c) in appendix) It is commonly used for passenger car which is for high speed usage. Its benefits are it has a better dispersal of water and increased performance and driving force. Unfortunately, this tread is mounted in direction.
Lastly, the asymmetric pattern tread is a tread that consists of different pattern on each side. (Refer to picture 2.6 (c) in appendix) This tread of tyre is the best if being driven in high speed as it has a larger contact area. It can also minimize the tread wear outside the tyre if the position is in the right way around. This is usually installed in motorsport or high performance tyres because of their larger contact area.
Hence, there are different tyres of tread which had been invented and created but all of the tread consists of different functions and purposes. The suitability of the uses of a tyre is different too but sometimes it can also be used in the same conditions of pavement. With the invention of the tread, the life of a driver could be safer as the breaking and the steering control is better.
2.8 Tyre Care
Now days, tyres are getting more expensive. As the technology involved in the production of tyre increase so does the price of tyre. Those with medium to low income owners have to carry out tyre car process to reduce the wear of tyres. In order to prolong tyre life span owners have to send their vehicles for rotating configuration, alignment configuration, balancing and tyre pressure.
Firstly, owners should do rotating configuration regularly. Car tyre experiences wear. Front tyres of all cars normally experience the most wear because they turn at an angle during steering and also because of weight transfers forward during a stop. A typical rotation pattern involves moving the front tyre to the rear of the same side. The rear tyres are then moved to the front but opposite sides of the vehicle. Some rotation patterns include rotation of the spare tyre. The spare tyre is inserted in the pattern at the right rear and reposition the tyre that supposed to be the rear tyre as the new spare tyre. Some tyres are designed for specific rotation only. They are rotated in the front-to-rear pattern and are cross rated only if they are removed from the rim so that they will rotate at their designed direction. Rotating tyres are recommended to be done every 5000km. Regular tyre rotation allows the tyre to wear out more evenly, allowing them to be replaced in completed sets. The effects of irregular rotation are excessive wear at the outer edges, excessive wear at the centre of the tyre and cupped or ocalloped wear.
Next is carrying out alignment configuration. As we travel across bumpy roads our tyres will bounce up and down. This causes our car tyres to be misaligned. There are four steering geometries that will affect misalignment. They are chamber, caster, and toe. Chambers involves the inward or outward tilt of a wheel viewed from the front of the vehicle. Chamber is the angle between the tyre and wheel and the true vertical line. The best alignment is zero chamber. A bad chamber will cause excessive wear on one side of the tyre. Next is caster. Caster is the angle difference between the steering axis and a true vertical line through the centre. There is a negative caster and positive caster. Negative is when the car tyre is bent outwards while positive is when the car tyre is bent inwards. This causes the car to 'pull' to the negative side making steering harder. Serious caster problems may cause the car to shimmy, which is shaking side to side which causes further tyre wear. Finally there is the toe. A tyre is traditionally pictured as a foot. The front edge of the tyre is the toe while the rear is the heel. A toe is the measurement between the front edges of the tyres same axle. A toe-in is when the same axle pointing towards each other and a toe-out is pointing away from each other. A zero toe is when the tyres axle is perfectly aligned. A bad cause a saw-tooth shaped wear on the tyre .This is why alignment configuration is crucial to prolong tyre lifespan. Alignment configuration is basically done with advanced machine. A monitor that displays the cars degree will assist the technician while he adjusts the bearings of the car.
Another method is carrying out balancing. Sometimes the rim of a wheel or the rubber of a tyre is thicker than the recommended thickness. Imbalances are also caused by hitting a pothole or curb. This causes the weight of the wheel to bias one side only. This makes the tyre and steering to vibrate damaging the suspension. Not only that, it also caused random bald spots wear, damage to steering components driver fatigue, impaired tyre traction and steering control and increased fuel consumption. Your wheels are unbalanced if the steering starts to shake after a certain speed. Even new tyres need balancing too. Balancing of new tyres is done as part of the fitting process. There are 2 types of balancing, the static balancing and the dynamic balancing. Static balance means that when the wheel is balanced, it does not have the tendency to rotate itself. Static balancing is used when there is unsightly weights are undesirable on the outside of the wheel. Dynamic balancing is used when there is dynamic imbalance. Dynamic balance means balance in motion. Dynamic wheel balancers spin the wheel and locate vibration in it. The computer splits the tyre into two halves and measure lateral and radial forces on each side of the tire's centre. Weights are added to the proper side by taping weights to the tyre rims. ( http://howto.yellow.co.nz/automotive-and-marine/vehicle-maintenance-and-repairs/how-to-tell-if-your-car-needs-its-wheels-balanced/ )
Finally is the air pressure of the tyre. Tyre pressure decreases over time. Low tyre pressure can bring bad consequences to the tyre. Some effects are excessive tyre wear at the outer shoulder, centre of the tyre and cracked tyres and poor fuel efficiency. Owners should maintain the tyres pressures to prevent these. This can easily be done by buying an inexpensive tyre gauge to measure the tyre pressure. It is important to regularly check the pressures of tyres. If the pressure is lower than the manufacturers recommended pressure, they can easily pump air into their tyres at majority of local petrol stations.