The principal constituents of car tyres are typically:
- Elastomers 42%,
- Carbon black & silica 28%
- Steel 12%
- Oils 6%
- Textile 5%
- Zinc oxide 1%
- Sulphur 1%
- Other ingredients 5%
Focus on natural rubber
Tyre manufacture accounts for 70% of the world production of natural rubber. Industry players have developed alternative plant-based sources of natural rubber to relieve pressure on supplies from rainforest plantations of the hevea tree as global demand for tyres increases.
Truck tyres contain typically 30% natural rubber, car tyres about 15%. Intensive research over many decades has not been able to identify an alternative synthetic material for heavy load-bearing tyres. A truck tyre typically requires 20 – 25kg of natural rubber which will need 200 – 250 m2 of cultivated land to produce.
The EU has listed natural rubber as a Critical Raw Material. This reflects the combination of high importance to the economy and high risk associated with supply.
Global natural rubber consumption is expected to rise from 12.5 million tonnes in 2016 to 17 million tonnes by 2025 largely driven by escalating demand from tyre makers in emerging market countries. In order to meet this increasing demand tyre manufacturers are working with rubber producers to improve cultivation efficiency.
Maximising resource efficiency through longer tyre life and increased use of retreaded truck tyres would also help to alleviate the threatened supply shortfall.