Guide on 10 Essential Parts of a Tire: Names, Functions & Diagram

The tire is a ring-shaped component that surrounds a 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. It is a crucial component of a vehicle as it provides the only point of contact with the road. It guarantees traction and permits movements like steering, braking, acceleration, and turning to be transmitted. For safe driving, selecting the correct tire is crucial, and being aware of each component can help you make an informed decision. The size of tires varies depending on the type of vehicle, yet all automobiles have comparable tire parts. Utilize our tutorial to fully understand the parts of a tire to increase your driving safety.

Car Tire Parts Diagram

Car Tire Parts Names

  • Beads
  • Beads Filler
  • Radial Cord Body
  • Inner Liner
  • Belt Plies
  • Sidewall
  • Tread
  • Tire Sipe
  • Tire Grooves
  • Tire Shoulder

Parts of a Car Tire


Beads are used to hold the tire with the rim of the vehicle. It is beneath the sidewall of two sides of the tire.

Beads are made up of high tensile steel wires with plating of copper, bronze, or brass, which wounds on rubber bands. The purpose of the bead is to prevent the sliding of the tire when the vehicle is in running condition.

Beads Filler

Bead filler is a rubber compound present inside the tire’s beads. It provides stability to the sidewall and bead area.

The density and stiffness of a tire’s bead filler are helpful, which gives more ideas to determine a tire’s performance which is very helpful for the long life of the tire without any damage.

Radial Cord Body

The radial cord body is also called body plies. This radial cord body is made up of several layers of plies, which gives better strength to the whole assembly.

This result will give more resistance to road damage. Polyester, rayon, and nylon are common materials used in radial cord bodies.

Inner Liner

The inner liner is the inside portion of the tire that is used to retain the air pressure. It prevents air from leaking; it acts as a tube of a tire. 

Belt Plies

Belts plies are more than two layers of cord that are made up of steel just below the tread area. Its function is to give strength, stability, flexibility also resistance to the tire. These belt plies are also providing more traction and grip to the tire.


The side of the tire is called the sidewall. It is the area between the beads of the tire to the tread. The sidewall is used to shield the inner part of the tire from damage, cuts, and scratches. The terminology is written on the sidewall of the tire. 

Parts of the tire with nomenclature and picture.

parts of tire with nomenclature

1. Tire Width: Tire width is the distance between two sidewalls of the tire. It’s generally measured in mm.

2. Aspect Ratio: The aspect ratio is nothing but a comparison of the height of the tire with the width of the tire. If the aspect ratio is 35 then the height of the tire is 35% of the tire width.

3. Construction: Construction means how the tire is built. Following is the typical construction notation.

R = Radial Construction
B = Bias Ply Construction
D = Diagonal Construction

4. Rim Diameter: Rim diameter is nothing but the actual diameter of the wheel when the tire is placed on it. It’s generally measured in inches.

5. Load Index: The load index is the actual load on the tire or how much load the tire can sustain. More load index sometimes results in tire bursts.

6. Speed Rating: Speed rating has a different later, which shows the maximum speed of tire can run.

7. DOT: DOT is abbreviated as the Department of transport. It is very useful to denote when the tire is manufactured.

8. Week: It denoted the in which week the tire is manufactured.

9. Year: The year represents the manufacturing date when the tire is being manufactured. Eg. 1220 is written on the tire then it can be read as the 12th week & year 2020.

Tire Sipe

These unique treads give adequate traction to the tire in varying climatic conditions. This sipe has little diagonal grooves, which help to get a better grip on the tire.


The tread is the outermost area of the tire. It is an actual area of the tire that comes in contact with the road. The tire tread is made of rubber and has a unique design and pattern.

This special design and pattern are used to get a better grip and traction of the tire with the load. So, it prevents the skidding and slipping of the tire.

The design and pattern of tread are largely depending on weather conditions and road conditions. It also differs from manufacturer to manufacturer.

Tire grooves

It is an area between two adjacent tread ribs called tire grooves. The purpose of tire grooves is to allow water to remove very fastly. It also helps to provide a good grip on the road. 

Tire Shoulder

The tire shoulder is the outermost border of the tread that includes the start of the sidewall. This tire shoulder gives more support and protection to the tire sidewall.

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