Tyres | Types Of Tyres | Speed Rating Of Tyres | Load Index Of Tyres | Tyre Inflation Pressure | Recycling Of Tyres

The invention of the wheel was one of the greatest invention of mankind. For a long time, the wooden and metallic wheels were used. These wheels served their purpose well and remained popular for long. But these wheels were unstable and prone to break on jerks. Also, they were not able to absorb road shocks and were not useful from the safety and comfort point of view. Later, the engineers improvised these wheels by putting a layer of rubber on their surface. This experiment proved to be quite useful and paved the way for the invention of pneumatic tyres. The development of pneumatic tyres added a new chapter to the history of wheels and revolutionized human mobility. These wheels not only improved the stability of vehicle but enhanced braking, cornering, mileage and comfort level of the vehicles.

What Are Tyres?

The rubber casing on the wheels used to hold the air is called tyre. These tyres provide traction to the wheels and maintain the stability of the vehicle. They provide cushioning to the wheels and protect the inner air tube from being damaged. They also improve the handling and Braking performance of the vehicle.

Materials Used In Tyres

Tyres are generally manufactured from Natural Rubber. They may also be made from synthetic rubber. The natural rubber is obtained from the latex of the Rubber tree while the synthetic rubber is made from the polymers obtained from petroleum. The natural rubber is a very soft and fragile compound. It is vulcanised by mixing sulfur in it. The sulfur provides the strength and elastic properties to the rubber. This rubber is further mixed with carbon black to improve its strength and wear resistance. The tyres are reinforced using steel wires and Nylon fabric. The reinforcement provides strength and resilience to the tyres. They make tyres durable and long-lasting.

Types Of Tyres

The tyre is designed keeping in mind the purpose they serve, the terrains they traverse, and the environmental conditions they are operated in. Based on their designs the tyres can be classified into 5 basic types:

1. Wet Tyres

Wet tyres are made from a softer rubber compound. Their rubber is designed to heat up quickly and offer good traction on wet tracks.

2. Winter Tyres

Winter tyres are designed for snowy and icy tracks. They are made from a special type of rubber which is capable of maintaining its elasticity even at extremely low temperatures. These tyres contain metal studs to penetrate inside the snow. The tread patches are kept larger and have lots of groves to remove snow under the tyres.

3. All-Season Tyres

These are the tyres used on all the general-purpose vehicle. They are made from harder rubber, keeping in mind the factors like durability and longevity. These tyres offer normal traction and grip over the road surface. Their cornering performance is also below average. Their main advantage is the longer life, which is a necessary factor for passenger vehicles.

4. Performance Tyres

Performance tyres are made from soft rubber. They offer excellent grip over the road and enhanced braking and cornering performance. They are specially designed for people who drive harder. Due to the softer compound, they do not last longer and wear at a high rate.

5. All-Terrain Tyres

These tyres are used in SUVs and small trucks. They have larger tread patches which offer excellent grip on muddy and loose surfaces.  They also offer good traction on wet tracks. They can be used on all the terrains and in all the seasons. They have stiffer sidewalls and offer good cushioning from jerks. They have a higher load index which allows them to carry larger weight.

What are Tubeless Tyres?

Tubeless tyres are those tyres which do not need separate tubes to store the air. These tyres are capable in themselves to hold the air inside them. These tyres contain the tubes as their inner lining, which provides leak-proof space to store the air inside. The tubeless tyres do not burst suddenly at the time of puncture. The air from the punctured tyres leak at a very slow rate and this provides sufficient time to the driver to reach the nearest puncture repair shop. Repairing a punctured tubeless tyre is not a big deal. Even a layman can repair it, if he has access to the repair kits 

Why Tyres Are Black?

The colour of the tyres is always black. This fact is so obvious that you might not be able to imagine a tyre which is not black. But, do you know the reason behind it? Let me tell you. The tyres look black because of the use of carbon black in their manufacturing. It is used to provide strength to the rubber. The original rubber is very soft and fragile. It can not bear the harsh conditions on the road. To increase its durability, carbon black is mixed with it. Carbon Black is also a good conductor of heat. It helps in conducting the heat away from the tyre surface to the road. This helps in keeping the tyres cool and also increases its life. You would be shocked to know that about 70 percent of the carbon black produces worldwide is used in making tyres. 

Why Tyres Have Treads On Them?

It is a common misconception that the treads on tyres are provided to increase traction with the ground. But this fact is just partially correct. The tyres without any tread have more surface to surface contact with the road and hence they produce greater traction. In fact, Formula cars use plane tyres for dry track races as they offer better grip over the track. But, these tyres can not maintain the same traction on wet tracks. This is due to a phenomenon called 'Hydroplaning'. It is caused due to the formation of a layer of water between the tyres and the road surface. This decreases the grip of tyres on the track making the vehicle unstable and unsafe on wet surfaces. To prevent this, tyres are provided with treads. These treads provide an escape for the water underneath the wheels, preventing the condition of Hydroplaning.  However, the off-roading tyres are provided with large size treads to improve the tyre grip on muddy and rocky tracks.

Speed Rating Of Tyres

Each tyre is designed for a specific load and speed condition. The Speed Rating of a tyre represents the maximum speed for which it is designed. Operating a tyre beyond its prescribed speed limits increases the rate of tyre wear and decreases its life. A sample speed chart is given below for your understanding.

Sr. No	Speed Rating	Max Speed
1	F	80
2	L	120
3	H	210
4	ZR	240+

Load Index Of Tyres

Similar to the Velocity Rating the Load Index represents the maximum load a tyre can bear. Beyond this load, the tyre may wear at a larger rate. For a given tyre the maximum weight it can bear may be found from the Load Index chart. One must always look at the Velocity and Load Index of the tyre before buying it. A sample Load Index chart is given below for your understanding.

Sr. No	Speed Index	Max Load
1	50	190
2	66	300
3	100	800
4	150	3350

Tread Wear Indicator

Wearing out of treads is a common problem in vehicles. Driving a vehicle with worn-out tread is unsafe and may even lead to accidents. We must always take care of them and replace the tyres once the treads are worn out. But how can we decide that the tyres need a replacement? This can be very easily decided by looking at the tread wear indicators. The tyre manufacturers provide these indicators on the tyre surface to keep people informed about the tread condition. These are small protrusion inside the tread grooves. They represent the level to which tread wear is tolerable. If the tread wears beyond them, the tyre becomes useless and need to be replaced.

Tyre Inflation Pressure

Maintaining optimum tyre pressure is necessary for better performance and long tyre life. Optimum pressure ensures uniform tyre wear and better handling. Driving with high inflation pressure may cause your tyres to wear faster and may even cause your tyre to burst. It can even decrease the ride comfort by providing bumpy rides. At the other hand, the lower inflation pressure may damage the sidewalls of the tyre and worsen the handling. It may also increase friction with the road and may negatively impact the mileage of the vehicle. So, it is extremely necessary to keep a regular watch on the tyre inflation pressure. We must ensure the tyre pressure as per the guidelines mentioned in the owner's manual.

Reading Tyre Specifications

All the major specifications related to tyres are mentioned on their sidewalls. We can read this information for a better understanding of the tyre of our vehicle. The code written on the tyre shown in the figure is 140/70-17 M/C 66H.

1. Width Of Tyre

The first term that is 140 denotes the width of the tyre i.e. 140 cm. 

2. Aspect Ratio Of Tyre

The second term 70 denotes the aspect ratio of the tyre. It means the height of the sidewalls of the tyre is 70% of its width i.e. 98 cm. From aspect ratio data it is clear that the above tyre is a wide tyre since its width is greater than the height of sidewalls.

3. Wheel Diameter

The third term represents the wheel diameter in inches. In the above example, it is 17 inches. In some tyres, you may find the letter 'R' written before the wheel diameter. This letter represents that tyre is radial type.

4. M/C

This particular term denotes that the tyre is for motorcycles

5. Load Index And Speed Rating

The number written after M/C is the tyres Load Index. The above tyre has a load index of 66. We can find out the max load capacity of this tyre by using Load index chart. The Letter after load index represents speed rating. The above tyre has speed rating H, which means the max speed for this tyre is 210.

Recycling And Reuse Of Tyres

The disposal and storage of the used and worn out tyres is a great problem  Each year lacks tyre become useless and scrapped. But have you ever thought where do these tyres go?  These worn-out tyres are used in two ways:

1. Used for landfills and construction.
2. Recycled and used as a raw material in manufacturing rubber items. 

For recycling the tyres, they are cut into very small pieces using tyre shredders. The steel wire fragments are then separated from the rubber using large electromagnets.  The rubber fragments are then screened to separate out extra-large rubber pieces. The screening process also removes other unwanted material from the tyre fragments. The next stage is cleaning. In this stage, the rubber fragments are cleaned using water or other cleaning agents. The cleaned rubber thus obtained is sent to the industries which use rubber as raw materials. In this way the useless and scrapped tyres are once again utilized for making goods like shoes, playing turfs etc.

So, friends, this was all about tyres. I hope it helped you. Please let me know if you liked it. You can contact me through our Facebook page or the contact form given at the bottom of this page.