All about tyres,what is the meaning of numbers on the Tyre? What is inside the Tyre?

Tyre, the basic unit of our vehicle was invented first in 1847 lodged by the Scottish inventor Robert William Thomson. Today’s world, there are variety of tyres you can buy depending on what their specialist applications are is long and varied.  Having a right type of tyre in a vehicle is very important, so in this article we will read about different types of tyre and its uses.

What is a Tyre?

Tyre is a ring-shaped structured wheel which is used to transfer the vehicle load to ground. Since their invention natural rubber is the most widely used material in manufacturing of tyres.At present time these circular rings are made up of rubber, chemicals, fiber, and chemical compounds. Compressed Nitrogen gas is filled inside the tyre.

Nitrogen gas is filled inside the tyre rather than air because

  • nitrogen is less likely to migrate through tire rubber than is oxygen, which means that your tire pressures will remain more stable over the long term.
  • If air is filled in the tyres, in a humid environment it can result in condensation inside the tires which can cause a problem.
  • Nitrogen molecules are larger than the molecules air so it can inflate the tyre for a longer time than air.
  • less fluctuation in tire pressure due to temperature.

What is the meaning of numbers on tire?


P195/55 R16 87 V this number tell about the construction, size, and type.

1 Cross section width 195

The first three numbers, in this case 195, refer to the section width of the tyre. This is the measurement, in millimetres, from the tyre’s inner sidewall to its outer sidewall.

2 Aspect ratio

The next 2 numbers 55 means the height is equal to 55% of the 195mm width. The bigger the aspect ratio, the bigger the sidewall will be.

3 Construction type

The letter R means the tyre is a radial construction. Almost all new car tyres are radials. In radial tyres the cord plies are arranged at 90 degrees to the direction of travel, or radially.

4 Rim

The number to the right of the construction type is the rim diameter, measured in inches. In this case, it’s a 16” wheel.

5 Load index 

The final number is the load index i.e. the maximum load (in kg) that the tyre can carry.

What is inside the tyre?

Thread: The tread of a tire or track refers to the rubber on its circumference that makes contact with the road or the ground.

Bead:  the bead is a rubber-coated steel cable whose function is to ensure that the tire remains attached to the wheel rim.

Layers:   These different layers are known as plies. Each layer is a different type of fabric. Polyester cord is the most popular ply fabric.

Belts: It is made up of steel and is meant to provide reinforcement to the section that’s directly underneath the tread.

Sidewall: It is made up of various natural and sidewall prevents air from escaping and keeps the body plies protected

What are the function of tyre?

  • To maintain contact between vehicle and ground by providing desired traction.
  • To support the load of vehicle.
  • Dealing with various forces acting on vehicle during its motion.
  • Providing cushion against shocks and damping them.



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