SGPU until today

Nº of vehicle tires treated:

Avoided emissions (t CO2eq):

Energy consumption avoided (GJ):

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Technical Information

Components and Characteristics of a Tyre

A tyre is a product composed of several materials with very different properties and whose manufacture implies a great deal of precision.


A tyre is made up of the following components:

  • A liner of airtight synthetic rubber . This liner is located inside the tyre and is the equivalent of the inner tube.
  • The casing ply , which is composed of fine textile fibre cords laid down in straight angles and bonded in rubber. These cords are a key element in the structure of the tyre and enable it to resist pressure. In each individual car tyre ply, there are about 1400 cords, each one being able to resist a force of 15 kg.
  • A lower bead whose function is to transmit the power from the engine and braking effort from the rim of the tyre through to the contact patch.
  • The bead wires help to hold the tyre onto the rim. They can bear a load of up to 1800 kg without a risk of breakage.
  • The supple rubber sidewalls protect the tyre from shocks that could damage the casing, such as minor shocks against sidewalks, holes, etc. A hard rubber ensures the connection between the tyre and the rim.
  • Bracing plies , made of very fine, but very resistant, steel cords, are crossed at an angle and bonded on top of each other. The cross of its cords with those of the casing forms in-deformable triangles.
  • The tread layer is laid over the bracing plies. This is the patterned part of the tyre that will be in contact with the road. In the contact patch, the tread must be able to resist very significant stresses. The tread compound must grip on all types of surfaces, resist wear and abrasion and heat up as little as possible.

Composition of Light and Heavy Tyres
MaterialLight TyreHeavy Tyre
Borracha / Elastómeros47 % 45 %
Negro de Fumo21,5 % 22 %
Aço16,5 % 25 %
Têxtil5,5 % --
Óxido de Zinco1 % 2 %
Enxofre1 % 1 %
Aditivos7,5 % 5 %

   Source: Convenção de Basileia, 1999

Element Analysis of Rubber
Carbon (%) 78-83
Hydrogen (%) 6-7
Oxygen (%) 3,5-5
Nitrogen (%) 0,2-0,4
Sulphur (%) 1 - 1,6
Chlorine (%) 0,07 - 0,1
Ash (%) 5 – 10

For more information see:

Basel Convention Series, Geneva, October 1999.pdf

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