The history of tire retreading is almost as old as the history of tires.
Today, the main sectors for tire retreading are aircraft, military vehicles,
school buses, off-the-road heavy duty vehicles, postal service vehicles,
taxi fleets, industrial vehicles, fire trucks, ambulances, racing cars,
etc. Retreading technology is well established.
On October 29, 1993, President Clinton signed Executive Order 12873 entitled 'Federal Acquisition, Recycling and Waste Prevention', which mandates the use of retreaded tires on all government vehicles.
Retread tires provide safe and dependable performance at a lower price compared to new tires.
Despite the fact that retread tires have been tested and proven dependable, the majority of individual car owners do not want to buy retreaded tires for their vehicles for a variety of reasons. The entire market for retreaded tires has decreased by more than 55 % over the last 8 years. In 1990, over 33.5 million tires were sold as retreaded tires, whereas only 16 million tires were sold in 1998. Even though the executive order mentioned above mandates retreaded tires for all government vehicles, this is a small share of the market compared to the large market for passenger tires, which occupied 81.5 % of the new tire market in 1998.
Note: Retreading is not counted as tire recycling in some reports on waste tire (solid waste) management. However, the extension of the product lifecycle has contributed to a decrease in various waste materials and disposal problems.
Manufacturing Process of Retreading:
Inspection: Each agency has established their own safety specifications. For example, the regulation standards for aircraft and school bus tires are different. Generally, the worn casing, cuts, punctures and overall damage are assessed before the tire is processed for retreading.Facts:
Repair: Nail holes, crown damage, and side wall can be repaired routinely.
Buffing: Buffing removes the unwanted or worn old tread. The technique depends on the design of the tire. The steel belt underneath the tread must not be exposed. Current tires have a 'base' compound layer between the tread and the belt. Improper buffing will cause tread separation during future use.
Recuring: New tread compounds (unvulcanized rubber compounds) are molded around the buffed tire and recured. This process is also dependent on the tire design. Tire manufacturers sell the rubber compounds for retreading in order to provide compatible materials.
Since the process requires high temperature, over-curing may cause damage to the casing. Needless to say, undercuring may cause tread separation.
Final Inspection: The retreaded tire is tested and inspected.
The tire production process consumes a large amount of energy typically equivalent to 22 gallons of oil for the manufacture of one new truck tire. Most of this energy is contained in the casing, which can be reused in a retreaded tire. As a result, it takes the equivalent of only 7 gallons of oil to produce a retreaded tire.
Retreaded tires will provide almost the same longevity as new tires and almost the same fuel efficiency to the vehicle as new tires. Depending on the design and original quality, a tire could get an average of three to four retreadings per casing.
Some myths and negative images of recycled products are often a major barrier. Some of these considerations pertaining to retreaded tires are discussed below.
1: Retreaded tires are less safe than new tires.
Fact: Statistics compiled by the U.S. Department of Transportation show that nearly all tires involved in any tire-related accidents were under-inflated or bald. Properly-maintained tires, both new and retreaded, do not cause accidents. Retreaded tires have been safely used on school buses, trucks, cars, fire engines, and other emergency vehicles for years.
2: Retreaded tires have a higher failure rate than new tires.
Fact: Failure on the road occurs with both new tires and retreaded tires, primarily from truck tires that are overloaded, under-inflated, or otherwise abused, as opposed to poor retreaded product quality. New or retreaded tire failures can be greatly reduced by following good maintenance, including proper mating with regard to diameter and tread depth and design, as well as maintenance of proper air pressure.
Because of the rapidly decreasing market for passenger tire retreading, the total retreaded tire market has shrunk by more than 55 % in the last 8 years. Some 'real' problems must be considered as part of the reason for the rapid decrease in passenger tire retreading.
In the passenger replacement market, retreaded tires do not provide a sufficient economic advantage compared to the cost of new tires. And nearly 100 % of passenger tires consist of radial tires.
Retreading is a well-established and proven technology but is not the ultimate solution for waste tire management.
A key to success is how to develop retreading as a viable option for the passenger tire replacement market. One necessary effort is to eliminate the barriers and negative images regarding retreading of used tires. Secondly, changes in the manufacturing and design of new tires are necessary to facilitate reusability. This would require legislative initiative.
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