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A tyre (or tire) is a circular ring-shaped component of a vehicle which is mounted on its wheel’s rim. It provides traction to the vehicle and transfers its load to the ground. A pneumatic tyre (tyre filled with air) also absorbs shocks generated by uneven surfaces.
The word tire is derived from the word attire. A wheel dressed with a tire is a dressed wheel (having attire).
A modern-day tire is made from natural rubber, synthetic rubber, wire, fabric along with carbon black and other chemical compounds.
A modern pneumatic tyre consists of two parts tread and body. Tread provides traction to the vehicle while body contains compressed air. Early rubber tires are solid which means they do not require air to provide them strength. Solid rubber tyres are still used today in some applications like lawn movers, casters and wheel barrows.
Tread of a tyre
Image attribution: CC BY 2.0, https://commons.wikimedia.org/w/index.php?curid=942417
Before the development of rubber, a tire was simply a metal ring mounted on a wooden wheel. The metal ring (tire) was first heated so that it expands then it is fitted over a wooden wheel. After cooling it shrinks and hence obtains a very tight grip on the wheel.
Wooden wheel with metal tyre
Image source: https://pxhere.com/en/photo/854017
We also use metal tyres today in locomotives and rail cars.
Wheel of a locomotive
Image source: By Slambo at en.Wikipedia – Photo by Sean Lamb (en:User:Slambo)Transfered from en.Wikipedia; en:Image:Steam locomotive driving wheel.jpgtransfered to Commons by User:Trengarasu using CommonsHelper., CC BY-SA 2.0, https://commons.wikimedia.org/w/index.php?curid=4795912
Based on their load carrying capacity automotive tyres can broadly be classified into three categories
- Light to medium duty tyres
- Heavy duty tyres
- Other purpose tyres
Light to medium duty tyres
Light duty tyres can carry a load of 250 to 500 kg while Medium duty tyres can carry a load of 500 to 1500 kg.
Light to medium duty tyres can further be classified as
(a). Winter tyres: These tyres are capable to hold grip on snow and ice.
(b). All season tyres: These type of tyres can be used in both winter and summers.
(c). All terrain tyres. These type of tyres can be used for both on road and off-road purpose.
(d). Mud terrain: These type of tyres are capable to run on mud.
(e). High performance tyres: These type of tyres are capable to run at a speed of up to 270 kmph.
(f). Ultra-high performance tyres: These type of tyres are capable to run at a speed up to 299 kmph.
(g). Run flat tyres: These type of tyres can run while they are punctured (though at a lower speed).
(h). Race car tyres: These type of tyres have less life but have high cornering and acceleration friction.
Heavy duty tyres
Heavy duty tyres have a load bearing capacity between 1800 kg to 2500 kg. Truck tyres and off road tyres are examples of these.
Other purpose tyres
It consists of aircraft, bicycle, motorcycle and industrial tyres like excavators, tractors, forklifts, bucket rollers and road rollers.
Tyre hazard
Tyre hazard can occur due to following two reasons.
- Failure of tyre: It can occur due to belt separation, running flat etc.
- Loss of friction: It can occur from snow, ice, tyre melt and soft ground.
Understanding alphabets, words and numbers embossed on a tyre
A modern pneumatic tyre has some numbers, words and alphabets embossed in it, which shows its specification.
For e.g. ‘Outside 225/40 ZR 19 93Y’
Outside means, this side of the tyre should be placed facing out of the vehicle.
225 is the tyre width in mm.
40 is the percentage of tire side height to its width.
R is used for radial bias plies, D for diagonal bias plies and B for belted bias plies.
19 is the rim size in inches.
93 is the load index
Y is the speed rating of the tyre.
An arrow symbol embossed on tyre shows the direction of its rotation.
Winter tyres and Studded tyres
What are winter tyres?
Winter tyres are specially designed tyres, which are to be used in the areas were friction in road surface is very low. These tyres have bigger tread design with bigger gap than those tyres which are used in summer days. These tyres are made to operate below 7°C.
However, even these tyres fail if a car desires to maintain a decent speed in such a slippery winter road. Hence, in this case we have to use specially designed studded tyres .
What are studded tyres?
Studded tyres are specially designed tyres fitted with studs (generally made Tungsten Carbide), to hold extreme grip even in the snowy road. They maintain a positive engagement with the road. Studded tyres pierce the snow and get the required grip to move through it.
These tyres generally made Tungsten Carbide, which is a very hard ceramic. Studded tyres can cause a huge damage to the roads, while driving in summer season. Hence, in many countries these types of tyres are only allowed in winter season and not in summer season.
There is a variety of Studded tyres available in the market as per the need of user. Some people even modify their ordinary car tyres themselves, to get exactly what they desire.
Image Sources
Winter tiers
Licence: CC0 Public Domain [Date: 09-12-2018]
Referral link: https://www.maxpixel.net/Snow-Auto-Tires-Mud-Winter-Tires-Profile-Mature-3198543
Studded tiers
Licence: CC BY-SA 2.0
Image URL: https://www.flickr.com/photos/royal_broil/25299025816