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A study on tyres
Updated: Jan 28, 2022
Before the wheel was invented, people used sleighs and the load was dragged along the ground. There was a great deal of resistance to forward movement unless the sleigh was able to slide easily over snow, ice or wooden rollers. Friction was high because the movement over the ground was equal to the speed at which the mass travelled.
To overcome this came the revolutionary invention of ‘Wheels’. Wheels allowed rolling and thus made movements easier. In vehicles the wheel is attached to the Hub and Axle, whereas tyre is simply the part that is made out of primarily rubber and assists the car with more practical movement. It surrounds the wheel’s rim to transfer a vehicle's load from the axle through the wheel to the ground and to provide traction on the surface over which the wheel travels. Spoked wooden wheels lasted until the modern era of coaches, and then usually with iron tyres. Even the first Benz motor car introduced in 1886, still had spoked wooden wheels, albeit with solid rubber tyres.
The figure below shows the cycloid curve (in yellow) traced by any general point on rim of a rolling wheel. Tyres provide a gripping surface for traction and serve as a cushion for the wheels of a moving vehicle.
Thus, the most vital thing is the tyre grip. If there were no such thing as grip, cars just would not be able to move at all. The wheels would just spin and therefore the driver wouldn't be ready to budge the vehicle. Even on a straight road and at a steady speed, there's no alternative to grip. This is because a moving vehicle has to deal with natural forces, such as the banking, the slope or the unevenness of the road, or rolling resistance, which are constantly trying to slow the vehicle down or push it off its path. Generating grip involves generating friction forces which counteract the vehicle’s skidding off the road. However, it must be borne in mind that it is slippage which produces the friction forces of grip. In fact, there are two forms of relative movement in the contact patch, micro-movement, commonly known as slippage, which counteracts macro-movement, commonly known as skidding.
Furthermore, even though the flattening of the contact area constantly produces
micro-movements between the tread blocks and the road surface, the contact area does not move– it changes, as one contact area continuously replaces the previous one.
It is only when the vehicle brakes, accelerates or corners that the contact area and the road begin to move relative to each other: this relative movement is known as slippage.
Slippage in the contact patch is produced when braking, acceleration, or cornering occurs. Here lies a paradox, which indeed is very surprising: “a tyre slips in order not to skid”!
WHAT is a tyre actually made of?
A tyre is primarily made up of rubber. Rubber is a viscoelastic material. A viscoelastic material is a deformable material with a behaviour which lies between that of a viscous liquid and an elastic solid. The harder the force applied, the greater the resistance to movement. The force F applied is not proportional to the travel, but proportional to the speed of the piston’s forward movement (Χ), i.e.; F = ηx˙. where η is the viscosity constant of the fluid.
On application of the force the, no immediate movement is observed. It is only after few moments that the movement becomes noticeable; thus, creating a lag between the force applied and the movement, this is called hysteresis.
On removal of the force, it may/may not return to its initial position (even if it does it is not always perceptible to naked eye). The energy supplied is not restored, but dissipated in the fluid: implying a energy loss (hysteresis).
Where does the viscoelasticity come from?
The constituent rubbers of the tyre are vulcanised elastomers. These elastomeric materials are made up of one or more polymers, long molecular chains which spontaneously take on the shape of a ball of wool and become entangled with each other.
To make the tyre, these materials are vulcanised, i.e., cured after incorporation of sulphur. Curing causes the creation of sulphur bridges between the polymer chains.
In moving, the segments of chains between the sulphur bridges rub against the other chains in their environment. It is this phenomenon which gives the material its viscous component.
Passenger car, lorry and off-the-road (“OTR”) tyres are products of complex engineering. They are made up of numerous different rubber compounds, many different types of carbon black, fillers like clay and silica, and chemicals & minerals added to allow or accelerate vulcanization. The tyres also have several types of fabric for reinforcement and several kinds and sizes of steel. Some of the steel is twisted or braided into strong cables.
A common-sized all-season passenger tyre, weighing about 10 KG (22 lbs) new, contains:-
30 kinds of synthetic rubber
8 kinds of natural rubber
8 kinds of carbon black
Steel cord for belts
Polyester and nylon fibre
Steel bead wire
40 different chemicals, waxes, oils, pigments, silicas & clays
Lorry & OTR tyres contain higher proportions of natural rubber than passenger car tyres.
Silica replaces part of the carbon black in certain types of tyres.
Some of the additives include clays, which may be replaced in part in some tyres with recycled rubber crumb from waste tyres.
These approximate totals would be slightly higher if clays were replaced by recycled crumb rubber from waste tyres.
Tyres contain so many different compounds and ingredients because they are engineering miracles, expected to handle the tortures of heat and cold, high speed, abrasive conditions, and often not enough air pressure. They are expected to perform for tens of thousands of miles and retain their essential properties despite horrendous driving habits and sometimes poorly maintained or built roads. Further, the addition of carbon black makes tyres tougher and more durable.
Crossply Tyres:
Crossply tyres consist of carcass layers made from nylon cord. They are placed diagonally across each other in the tread and the sidewalls, at an angle of 55 degrees. Multiple rubber plies overlap each other and they form a thick layer, resulting in less flexibility which can make it more sensitive to overheating. Therefore all high speed Tractor tyres are of Radial construction. Crossply tyres provide a strong and rigid sidewall which tries to follow the natural lines of the road and this can cause a tyre to overheat when it is used on a hard road surface and this in turn, causes the tyre to wear out more quickly. However, the sidewall of a crossply tyre is more rigid than that of a radial tyre so is more resilient at preventing sidewall damage. Crossply tyres are therefore sometimes used if sidewall damage is a problem.
Advantages of crossply tyres include:
Improved vehicle stability
Higher resistance against sidewall damages
Cheaper to produce
Disadvantages of crossply tyres include:
High rolling resistance, which causes tyres to quickly heat up
Reduced comfort due to the tyre's rigidity
Increased fuel consumption
Radial Tyres:
These tyres are able to absorb shocks generated by road surfaces. The cords in a radial tyre casing run perpendicular to the direction of travel. Viewed from the side, the cords run radially - giving the tyre its name. The flexibility of a Radial tyre, together with its strength, are two combined factors which mean a radial tractor tyre absorbs impact shock and bumps more effectively than a crossply tyre. However, the cords cannot sufficiently absorb lateral forces when cornering or circumferential forces when accelerating.
The flexibility of the sidewall enhances vehicle stability and provides maximum contact of the tyre with the road surface. This, in turn, leads to a more comfortable ride and allows the driver to work longer. These tyres are also stronger, which means machines that use tyres like truck tyres or tractor tyres can be operated at higher load capacities. These are ones being used in the modern cars mostly.
Advantages of radial tyres include:
Good steering ad better road contact
Improved driving comfort thanks to flexible sidewalls
Less heat generated in the tyre at high speeds
Higher resistance against tread-related damage
Lower fuel consumption through better transfer of energy from machine to road
Disadvantages of radial tyres include:
The soft sidewalls are vulnerable when, for example, vehicles collide with curb stones.
Minor bumps in road are dealt with less effectively because radial tyres feature a steel belt.
Height to Width Ratio:
This is yet another important feature of the tyres. A height-width ratio (aspect ratio) of 65% is standard for many vehicles today and modern tyres are getting even wider – now having a height-width ratio as low as 25%. These ultra- low-profile tyres are, however, built for special high-performance cars.
Since 1975 the maximum speeds possible with Continental tyres have risen from 210 km/h to 350 km/h. At the same time the weight of an average-size tyre has actually been reduced from close to 12 to a good 8 kilograms.
The tread/belt assembly provides a minimal rolling resistance, optimal handling and a long service life. In the early days of tyre development, the casing was made of square woven linen fabric embedded in rubber. However, the crossed treads of the fabric cut away at each other, resulting in a relatively short tyre life.
In high end vehicles generally the Height to width ratio is kept low for better handling response, whereas the higher ratios are used in cases where more cushioning or riding comfort is desired.
How to read a Tyre?
Type: It precedes the Tyre Width Marking. P stands for passenger, LT stands for Light Truck, If there are no letters at the beginning, this indicates a Euro metric tyre.
Tyre Width: It is the width of the tyre measured in millimeters from sidewall to sidewall.
Aspect Ratio: Is the ratio of the height of the tyre's cross-section to its width.
Construction: The letter "R" in a tyre size stands for Radial, which means the layers run radially across the tyre.
Wheel Diameter: Is the size of the wheel measured from one end to the other. It tells us the size of the wheel that the tyre is intended to fit.
Load Index: It indicates the maximum load that the tyre can support when properly inflated.
Speed Rating: The maximum speed capability of a tyre.
Tyre Indication Number: The series of letters and numbers following the letters "DOT." The TIN consists of up to 12 numbers and letters to identify the factory location and the week and year the tyre was manufactured.
Tyre Treads:
Tyres used on public roads must have a tread pattern by law. The main job of the tread pattern is to expel water which can affect the tyre’s contact with the road in wet conditions. In addition, the tread pattern, especially that of winter tyres, provides grip and adhesion.
On wet roads at high speeds, a wedge of water can build up between the tyre and the road surface. The tyre may then start to lose road contact or aquaplane, and the vehicle can no longer be steered.
Sufficient tread depth is vital not only in such extreme situations. Even at low speeds, there is a greater risk of having an accident in wet weather if the tyres are worn.
In order to ensure the tyres always offer best possible performance, summer tyres should be replaced when they reach a depth of 3 mm, and winter tyres when they reach a depth of 4 mm. Also, all four-wheel positions should be fitted with tyres of the same tread pattern design3, and each axle, at least, should have tyres with the same tread depth.
The tread pattern used on a winter tyre is particularly effective on snow and slush. In these conditions, the rotation of the wheel presses the snow into the wider grooves used on this type of tyre, thereby generating additional traction. When setting off, rows of fine lateral sipes enable the tread blocks to flex and bite deeper into the ice or snow for better traction.
It is vital that winter tyres are always kept inflated at the correct pressure since the volume of air contained in the tyre decreases at very low temperatures.
Summer rubber compounds begin to harden below 7 °C and no longer provide the levels of grip required and the tyre grip acts as if a glass. The special technology offered by winter tyres means they remain flexible and offer sufficient grip even at low temperatures.
The tread pattern used on a winter tyre is particularly effective on snow and slush. In these conditions, the rotation of the wheel presses the snow into the wider grooves used on this type of tyre, thereby generating additional traction. When setting off, rows of fine lateral sipes enable the tread blocks to flex and bite deeper into the ice or snow for better traction. They are designed to channel snow and slush and expel water.
The Graphs below show the variations in the tread rubbers with temperature-
Surface Friction Coefficient:
To have a better understanding we must accustom ourselves with some basic terminologies.
Microroughness: This is the name given to the road surface texture when the distance between two consecutive rough spots is between 1 and 100 microns. It is this degree of roughness which is mainly responsible for tyre grip.
Macroroughness: This is the name given to the road surface texture when the distance between two consecutive rough spots is between 100 microns and 10 millimeters.
Friction coefficient varies with molecular adhesion (due to Direct Contact) and Roughness Effects (Frequential Excitation caused by the surface due to slipping). If the depth of water increases (wet surface), Microroughness might become flooded. Macroroughness continues to indent, drain and store, but there is a risk of aquaplaning at high speed.
Water therefore interferes with grip and the tyres must be designed to disperse this water quickly and effectively by adjusting the shape of the contact patch, the tread pattern and the sipe arrangement.
Many vehicles are fitted with all season tyres when they leave the factory. Since they are built to provide a relatively quiet ride, good tread life and year-round performance, its no wonder why they are so popular. All season tyres offer versatile performance and are designed to perform in a variety of conditions including wet roads and light winter driving. All season tyres are designed to offer a combination of benefits from summer and winter tyres.
At temperatures between -5 and 0°C, the pressure of the tyre on the road causes slight surface melting of the ice, which is in turn covered by a thin film of water. The ice is then like a flooded microsmooth surface. Besides, the slopy nature of roads also help in draining snow from the path.
Snow and ice are cold surfaces which require the use of tyre compounds that retain a moderate modulus at low temperatures.
Slippage:
When the Brakes are applied, the angular speed of the wheels decreases and the rolling speed of the tyre drops below the vehicle speed. To compensate for this difference, the tyres begin to slip on the road at a slippage rate G.
During slippage, molecular adhesion and indentation induce a friction force, which opposes slippage, and the vehicle slows down
G = (ωR – V)/ V
G tends to infinity when ωR>>V, this happens when the wheels go round but do not move forward which is the case when we travel on snowy roads, the excessive slippage observed is just a consequence of this G equals -1 when the wheels get locked. Here the wheels continue to slide forward but do not roll.
This happens when the brakes are applied too sharply on icy surfaces or also when the vehicle has no ABS.
Cornering:
While cornering all the forces passes through the contact patch. The driver points the front tyres towards the inside of the bend and not actually along it as might be expected. This creates an angular difference called the slip angle. The slip angle in the rear wheels is developed in the wheels naturally due to this movement.
The ratios between the slip angles of the front and rear axles (a function of the slip angles of the front and rear tyres respectively) will determine the vehicle's behaviour in a given turn. If the ratio of front to rear slip angles is greater than 1:1, the vehicle will tend to understeer, while a ratio of less than 1:1 will produce oversteer. Understeer refers to the tendency to travel in a straight line during a bend. While oversteer is the tendency to take a tighter turn than intended.
How is a tyre manufactured?
Now let’s discover the processes involved in the manufacturing of a tyre.
Blending
As many as 30 ingredients which include Natural rubber, Synthetic rubber, Carbon black, Sulphur and several other chemicals and oils go into the rubber blend of a tyre. All such ingredients are made to go through computer controlled gigantic machines called Banbury mixers. Here these are treated under tremendous heat and pressure to soften the rubber evenly distribute the chemicals. The output is a gummy black compound that is sent for milling.
Milling
Each such batch goes through rolling mills that squeezes them into thick sheets. These sheets are used for making different parts of the tyre. Further polyester sheets are unrolled onto a machine called calender. This machine is equipped with rollers which apply warm rubber to both sides of the fabric. This produces rubberized fabric that is used to reinforce the tyres and make the tyre sturdier.
Building
This process is performed on a cylinder whose central flexible section can be inflated. The first element applied to the drum is a sheet of airtight synthetic rubber, this layer replaces the inner tube in today's tyres.
In a second stage a ply made of textile core sheeted rubber is added which forms a reinforcement radiating around the tyre it is the radial carcass. Two high resistance metal cable hoops are installed against strips of profiled rubber. Then the bead wires which will hold the tyre on the rim are installed. The casing ply is folded over the beads to anchor it. Other elements are then added. Sidewalls made of flexible resistant rubber are installed which will protect the tyre from lateral damage. The tyre is then shaped by inflating the central section of the drum. Two plies are applied to the crown of the tyre, they are reinforced with metal wire arranged completely and with the casing fly form a network of triangles to limit the deformations of the tyre.
Curing
The tyre blank is then installed in the curing mould. In the centre, a bladder filled with pressurized hot water pushes the still malleable material to the base of the patterns engraved in the mould the heat of the water and steam surrounding the mould causes curing to begin. The rise in temperature causes vulcanization of the rubber, the sulphur incorporated into the rubber components forms bonds between the polymer chains. At this point the rubber switches from a plastic state to an elastic state. The treads and sidewall markings are added inside the curing mould. The tyre is then removed from the mould with definitive form and properties.
Inspection
Every tyre is carefully assessed by trained inspectors. Special machines are also used, designed to spot even slight imperfections. Quality control engineers randomly select tyres from the line and cut them open for closer inspection. In addition to this, some tyres are chosen off the line and x-rayed individually, to check for internal weaknesses.
Why different tyres for different applications?
The earlier discussion on slippage and surface friction coefficient makes it clear that a single tyre cannot be used all purposes. The possible terrains which a vehicle can be used for is too wide. There are all terrain type tyres as well. They may not deliver the optimum performance , but can easily give adequate performance on all types of terrain.
Snow tyres have metal or ceramic studs that protrude from the tyre to increase traction on hard-packed snow. Further they have the tread blocks set fairly far apart in order to ensure better grip in the snow. Ice tyres on the other hand are made up of blocks, set very close together, many tiny incisions in the blocks ensure a quieter performance. Further, the tread on ice tyres is usually manufactured from a mix of silica.
Off Road vehicles are those which are used for unpaved surfaces like loose dirt, mud, sand, or gravel. Compared to ice or snow tyres, they lack studs but contain deeper and wider grooves meant to assist the tread sink into mud or gravel surfaces. They use thick and deep treads that penetrate into the mud and dirt to provide more traction. Tough off roading conditions are also faced by ATS and rescue operations teams.
Besides these, tyres are used for space probe vehicles as well. Here the surface conditions where the vehicle might travel and the possible obstacles it might face is quite uncertain and needs to be estimated.
The surfaces have over pointed rocks and are usually very uneven, at times like a plateau and at other times like valley. Further the challenge is of exposure to UV radiations at these surfaces and the extreme temperatures here which can fall down to as much as -130°C, at which the rubberized material tends to lose its elastic property and turn brittle like glass, thus rendering it completely useless.
The challenge that further needs to be overcome is to produce the tyres with minimal weight capable of supporting heavy rovers so as to reduce the overall launch cost.
All these challenges have motivated scientists to discover new materials which can be used to make the tyres. One such material is Nitinol. It is an alloy of Titanium and Nickel. This is actually the same material used for teeth braces, it possesses shape memory and can easily revert to its original shape when adequate requirements are met.
Nitinol exists as Martensite below certain temperature. On the application of sufficient stress, it undergoes deformation, unlike other materials it uses the heat generated by moving over uneven surfaces to revert back to austenite (regularly ordered crystal structure) which on further cooling attains the original shape. Interestingly this transition temperature can be tailored for different applications.
The Curiosity rover uses 0.75mm thick wheels (as of a credit card) and treads which are 6.4mm thick. The above image shows the damage that the rover suffered after travelling on the surface.
The Lunar rover used flexible steel mesh wheels, with a stiffer inner frame to prevent over deflection and thin strips of metal attached to prevent the wheel from sinking into the lunar soil.
NASA Rovers are using wheels of aluminium, with cleats for traction and curved titanium spokes for springy support.
Further newer innovations for space probes are being extensively thought of, to ensure successful explorations in space.
The Future of Tyres:
It’s very easy to think that something as trivial as a tyre will never be revolutionized, but there are always ideas and opportunities for people willing to put the work into thinking about them. Engineers and scientists all round the world have come up with many amazing concept tyres, that aren't very faraway to be seen in the real world.
The motivation for developing better tyres comes from:
Every year 200 million tyres are scrapped prematurely due to punctures or irregular wear.
Lesser emissions, Lesser waste and stronger materials, Longer Life, Using Lighter and Lesser materials in production.
In countries with bad road conditions half of the tyres do not reach end of their life due to side wall damage.
Using Recycled materials in production of tyres.
Reducing the manufacturing cost by adopting techniques like 3D Printing.
Airless Tyres:
No Air pressure means flat tyres. Not Really. These tyres are non-pneumatic, unlike the present-day pneumatic tyres which either have a tube or are tubeless (have air filled in the space between the rims and the wheel). The inner structures of these tyres support the weight. Airless tyres will cut down on the use of energy and raw material used to produce spare tyres, thus freeing up deck space of the vehicle as well. As these are airless no flats, punctures or leaks would ever occur.
These are made up of recyclable materials and support the weight of the vehicle using the inner structures or the web. The web flexes and deflects allowing no particles to get stuck inside. These tyres might be more expensive but definitely worth the cost of ownership which is very low due to its longer life, lesser maintenance cost and a significantly reduced cost per mile.
The Michelin Uptis prototype shown above is created using three materials - rubber for the tread, aluminium for the wheel spokes and resin embedded fibre glass for reinforcement and is likely to debut in 2024.
Oxygene Tyres:
What special can a tyre do? Goodyear unveiled an amazing concept tyre at the Geneva Motor Show, which is filled with living moss that absorbs moisture from the road, before converting it into oxygen through photosynthesis. Oxygene was conceived as a response to research revealing the impact of unsafe air quality levels in urban areas. The tyre generates electricity by converting carbon dioxide into oxygen, which then also powers its electronic features such as an artificial intelligence processing unit and sensors.
The tyre is capable of cleaning the air that we breathe. Oxygene absorbs moisture from the road through its unique tread and inhales CO2 from the air to feed the moss in its sidewall and release oxygen via photosynthesis. With about 2.5 million tyres on the road, this would generate nearly 3,000 tons of O2 and absorb more than 4,000 tons of CO2 per year.
This is a tyre 3D printed from the rubber powder of recycled tyres. It will be lightweight, shock-absorbing, and puncture-free. Further, the tyre’s open structure would help in improving wet grip by absorbing water from the tread. Further, it uses LiFi, which enables the tyre to connect to the Internet of Things, allowing vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) data exchange, which is critical to smart mobility management systems.
Reconfigurable-wheel-track (RWTS):
These are the tyres developed under DARPA’s ground x- vehicle technologies programme. These wheels reconfigure to triangular tracks to instantly optimize mobility over different types of terrain. RWTS can change from wheel to track and back again within two seconds while the vehicle is in motion.
Wheels permit fast travel on hard surfaces while tracks perform better on soft surfaces. The transition increases the contact patch for instant improvements to tactical mobility and maneuverability on diverse terrains. This tyre is capable of this transition in mere “2 seconds”. This makes it possible for the fire to adapt to different terrains quickly. The Reconfigurable Wheel-Track system was initially designed to improve the mobility and effectiveness of combat vehicles.
Microbial Tyres:
Tyres made from Microbes. Over 25 litres of oil are used to make one tyre and over a billion tyres are produced worldwide each year. Isoprene is a major building block of synthetic rubber and is currently made almost entyrely from petrochemical sources. This compound is naturally produced by some plants when under heat-stress, but like natural rubber, it is not economically viable to harvest it from plants.
To address this, researchers around the world have been turning to microbes. For example, scientists in China have recently hijacked the pathway that the marine bacterium Synechococcus elongatus uses for photosynthesis, altering it to produce high quantities of isoprene in the laboratory while using carbon dioxide as fuel.
Meanwhile, researchers in the US are using carbohydrates from plants as a feedstock for specially designed yeast that ferments those carbohydrates into low-cost alcohols. They’ve now developed an add-on chemical process that then converts the alcohol into isoprene.
It is not only our vehicles that these developments will benefit – building blocks for rubber are also used to produce rubber-based products used in a wide range of industries, including the medical and construction industries.
Spherical Tyres:
Wheels are round! This is an established mindset among all of us. But engineers have broken this preconceived notion of having circular by coming up with spherical tyres. These are embedded with sensors and use IoT to communicate with other vehicles to prepare them for the road ahead. GoodYear Eagle 360 is a spherical tyre that is connected to the car by
Magnetic Levitation which suspends the tyre from the car by a magnetic field. Powered by artificial intelligence, the Eagle 360 Urban tyre is covered in a "bionic skin" of sensors made from super-elastic polymer. It has a sponge-like groove design which softens when wet to create deeper grooves for aquaplaning resistance besides water gets ejected through centrifugal force as well due to its spherical design. The groove design stiffens when dry to deliver optimum driving performance. A layer of foam under the tread ensures a larger contact patch. With easier and fluent lateral movements, it can overtake obstacles without changing direction. Sensors register road conditions and adjust the speed accordingly (slippery roads lower speed). It also communicates with other vehicles behind to make them prepare for the road ahead. Sensor register wear, tyres reposition to optimize wear and extend mileage.
Due to the fluent lateral movement, the parking efficiency also gets increased resulting in a greater number of cars being parked within the same parking space. It has maneuverability and can rotate in all directions.
The material required would be certainly more, making them expensive. Though using these tyres for leaning vehicles like motorcycles might not be a very good idea, this is definitely a revolutionary concept.
Super-elastic Tyres:
A Flat Tyre in space sounds Horrifying! Developed by NASA, these superelastic tyres are built to withstand the rocky terrains of Mars. Best of all, these sturdy tyres engineered for space use also make for viable alternatives to pneumatic tyres right here on Earth.
The novel use of shape memory alloys capable of undergoing high strain as load-bearing components, instead of typical elastic materials, results in a tyre that can withstand excessive deformation without permanent damage. These are completely puncture-proof and uses shape memory alloy as radial stiffening elements to increase the load-carrying capacity of the tyre treads.
These Tyres being both light and capable of bending confront to the terrain without permanently deforming. These tyres use the same material Nitinol that we said above. It gives the property of super-elasticity which allows these new Mars rover wheels to deform right down to the rim and still recover its shape after.
This combined with the interlocking coil design allows the tyre to tolerate strains in a way no other tyre could, while surviving the harsh Martian environment. These shape memory alloys are capable of undergoing significant reversible strain (up to 10%), enabling the tyre to withstand 30 times more deformation than other non-pneumatic tyres before undergoing permanent deformation. It can moreover handle heavier loads and higher speeds.
Dandelions:
Dandelions are a nuisance! But at Continental, the flowering weed is embraced as a key component to the future of tyres. Continental isn’t using just any dandelion but a specific species. The Russian dandelion is the only one that can be used as an alternative source for natural rubber production. Continental is unveiling tyres for trucks and buses made from natural rubber derived from dandelion roots. Continental is working on a replacement for
rubber known as Taraxagum. The first Conti EcoPlus HD3 made from this innovative and sustainable dandelion rubber were manufactured in summer 2016. It aims to use dandelion rubber as a sustainable alternative to the rubber from the rain forest, while at the same time reducing CO2 emissions, thanks to short transportation routes.
Intelligent Electric Tyres:
These tyres will monitor the wear and performance of the tyres and adapt to the temperature and road conditions effortlessly. They will track the tyre inflation pressure and temperature as well. The Smart Strain Sensor will be able to measure the dynamic change in the strain that occurs when a tyre is in use. Detecting a potential issue way earlier would definitely ensure safer rides. GoodYear reCharge Tyres are made with a biodegradable tread compound that can be recharged with individual capsules radically simplifying the process of replacing the tyres. The customized liquid in the capsules recharges the tyre grip
enabling the tyre to adapt over time to climatic circumstances and conditions or simply as per how one wants to travel.
The tread compound is reinforced with fibers inspired by one of the toughest natural materials in the world, Spider Silk. It helps to build a tread that is both extremely durable and sustainable. The tread is supported by a lightweight non-pneumatic frame and tall and narrow shape requiring extremely low maintenance.
Piezoelectric Tyres:
They charge themselves amidst journey. Piezoelectricity is the property to generate electricity in response to applied mechanical stress. The tyres are designed to capture both heats from the sun and the heat generated by the tyres flexing while the car rolls down the road. The heat energy is converted into electricity that recharges the car's batteries. GoodYear BH03 tyre is shown alongside which is based on this concept. The brittle nature of most piezoelectric materials is a major issue of concern. There are a variety of natural and
engineered piezoelectric materials, but none are both efficient and soft. The piezoelectric material would have to be exceptionally efficient, very soft and/or attached to a wagon wheel to get significant power out. There are plenty of challenges which need to be overcome to bring such tyres to the real world, but this one is certainly the tyre of a dream car that one sees which continues to travel endlessly.
Re-treadable Organic Tyres:
3D Printing on the Go! French tyre manufacturer Michelin released a concept for a 3D-printed tyre that is airless, puncture-free, connected, rechargeable, customizable, and completely maintenance-free at the 2017 World Summit on Sustainable Mobility.
Made using biodegradable materials derived from sources like Orange Zest, the Vision concept tyre doesn't rely on air, but on an interior mechanical architecture that is able to support the vehicle's weight. The tyre is also equipped with sensors that provide real-time information about its condition, and an accompanying app allows the user to change the tyre’s treading as needed.
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