From Ecopedia

Overview

Tires are ring-shaped outer rubber coverings of a vehicle, which offer protection as well as enhanced vehicular performance through flexible cushions that absorb shocks while keeping the wheels close to the ground.

Rubber is the fundamental material used in modern tire manufacturing along with other chemical compounds.

Rubber tires consist of:

- A tread, which provides traction

- A body, which gives support to the tire

Prior to the invention of rubber tires, vehicle tires were made up of simple metal bands fitted around wooden wheels.

Pneumatic tires

John Boyd Dunlop developed the first practical pneumatic tire in 1887.

A vast majority of tires today are pneumatic tires, made up of doughnut-resembling body cords and wires that are encased in rubber and fitted with inflatable cushions containing compressed air.

Pneumatic tires are extensively used on various types of vehicles including: - Bicycles - Motorcycles - Trucks - Cars - Earthmovers - Aircrafts

Types

While motorcycle tires and bicycle tires are fitted on spiked rims, car and truck tires require inner rubber tubes for holding air pressure.

Rubber tired-cars are made of flexible rubber reinforced with fabric and wires to ensure excellent wear and tear and high-resilience properties.

Maximum Natural Rubber Consumption

Over a billion Pneumatic tires are currently manufactured in around 450 manufacturing sites across the globe, making the industry, a leading consumer of natural rubber.

Other raw materials such as carbon black and other chemicals are utilized in pneumatic tire production.

Environmental Issues

Tread designing and interaction of tires of cars, bicycles and trucks with varied road surfaces produces considerable impact on sounds producing noise pollution from moving vehicles. As vehicular speeds increase, the sound intensities also rise accordingly.

Discarded tires known as scrap tires are a matter of great concern for environmentalists. Scrap tires often find reuse in bumper car barriers as well as weights that hold down tarps among many other things.

In most cases, scrap tires are recycled and processed into newer products or sold to licensed power facilities for fuel.

Certain scrap tires are sometimes retreaded for further use. Many state regulations are underway in the US to address the issue of dumping, mosquitoes and fire hazards caused due to scrap tire dumping in open fields.

Combustion of tires leads to production of hydrocarbons and other pollutants into the ground as well as ground water due to extreme temperatures and heat from a fire. Tire combustion releases the harmful black smoke, which is considered as an environment-harming contaminant.

While driving on roadways, tiny tire particles might worn off and get released into the air and possibly in nearby water, causing both air and water pollution.

Due to the presence of heavy metals and other harmful pollutants in tires, a potential risk exists for leaching of toxins into groundwater, when the tires are placed in wet grounds. Various studies proved that certain heavy metals, zinc, rubber and vulcanization chemicals as well as shredded tire pieces leach into water bodies from tires. Such contaminated tire water is shown to cause threat to some organisms.

References

http://en.wikipedia.org/wiki/Tire http://www.sciencedaily.com/releases/2002/11/021126204056.htm http://www.ehhi.org/reports/turf/ http://www.ejnet.org/rachel/rehw439.htm http://en.wikipedia.org/wiki/Tire_recycling http://www.vulcana.net/ http://www.ncbi.nlm.nih.gov/pubmed/9216257 http://www.energyjustice.net/tires/ http://auto.howstuffworks.com/tire5.htm http://www.researchandmarkets.com/reports/665693 http://en.wikipedia.org/wiki/Vulcanization