Retreading of tire

Retreading is one method of recycling. Also, it saves energy It takes about 831 of oil to manufacture one new truck tire whereas a retread tire requires only about 261. The cost of a retread tire can be from 30 to 50% less than a new tire (Myhre and MacKillop, 2002 2002 Fact Sheet, 2002). Approximately 

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The second best option would be remanufacturing [97]. Retreading of tires comes in this category, as would, more in general, the provision of a nanocomposite product that has been subject to wear and tear with a new surface layer. 

FIGURE 26.75 Comparing the rate of wear of a retread bias tire with a commercial radial ply tire (a) one tire each mounted on the trailer axle (equal force comparison) and (b) two tires of each group mounted and run consecutively (equal slip). 

This method involves the removal of mbber particles from tire tread by abrasion and is confined to the preparation of tire buffings, which is obtained as a by-product of retreading. It is a normal practice in industries to reuse tire buffings to make low-technical products by the revulcanization of the powder or by using the powder-sintering process. 

A large proportion of the circa 3.7 x 106 t/yr of natural mbber used in tires is consumed in tmck tires, off-the-road tires, and aircraft tires, all of which demand a low heat buildup performance. The retreading of tmck tires was also the province of natural mbber until the precured process was developed. Prior to the advent of this technique, the tack of natural mbber was essential for the unvulcanized mbber to adhere onto the buffed carcass, and the thickness of the shoulder region was such that the low heat buildup of natural mbber was essential to ensure that no failure occurred in service. With the precured tread process neither of these attributes were necessary and, synthetic mbber, which was and continues to be used, was found to give particularly good wear performance under low severity conditions, especially in the United States. However, work (56) has shown that natural mbber-based formulations can be developed which give a similar order of wear performance to the all-synthetic mbber tread, but with the additional benefit of lower rolling resistance, and hence better fuel economy. 

The third source reduction measure which can extend the useful tire life, and therefore reduce the number of tires scrapped, is retreading. Retreading is the application of a new tread to a worn tire that still has a good casing. Retreading began in the 1910s and has always played a role in the replacement tire market. 

There are various ways to recycle waste tire rubber. The first approach consists of reducing the tire rubber into scrap rubber. Sometimes, before retreading old tires with new rubber, the part of the tire that needs extracting is converted into scrap. 

Under the license from the University of Akron for the ultrasonic devulcanization technology, NFM Co. of Massillon, Ohio, has built a prototype of the single-screw extruder for ultrasonic devulcanization of tire and rubber products (Boron et al., 1996 Boron, 1999). It was reported that retreaded truck tires containing 15 wt.% and 30 wt.% of ultrasonically devulcanized carbon black-filled SBR had passed the preliminary dynamic endurance test (Boron, 1999). 

The percentage of tire retreads for cars is approx. 21 %, for light trucks 4 %, for trucks 75 %. The difference in price compared to new tires is 30-40 %. 

A number of methods [11,13-17] have been applied in an attempt to solve the problem and to find more effective ways of tire rubber recycling and waste rubber utilization. These methods include retreading, reclaiming, grinding, pulverization, microwave and ultrasonic processes, pyrolysis, and incineration. Processes for utilization of recycled rubber are also being developed, including the use of reclaimed rubber to manufacture rubber products and thermoplastic-rubber blends and the use of GRT to modify asphalt and cement. 

A As the lifespan of each kind of tire is different (7 years for the radial and just 2 years for the retreaded tires), an easy way to compare both alternatives is by calculating the annual cost of each kind of tire. The annual cost of the radial tires is 143.30 and for the retreaded tires it is 152.70. The radial tires are not only a bit cheaper per year but also safer. 

Check condition of tire. Passenger vehicles cannot be operated with regrooved, recapped, or retreaded tires on the steering axle. Check for improper inflation, serious cuts, bulges, tread wear and, if questionable, measme major tread groove depth. 

General Description Headlamp Concealment Devices Hood Latch Systems Theft Protection Vehicle Identification Numbers Windshield Mounting Motor Vehicle Brake Fluids Child Seating Systems Power-Operated Window Systems Side Door Strength Flammability of Interior Materials Air Brake Systems Exterior Protection (Bumpers) Retreaded Pneumatic Tires Roof Crush Resistance Motorcycle Brake Systems Warning Devices. 

In 1995, about 28-30 x 10 tires were retreaded (54). Retreading has been the most cost-effective alternative to recycling mbber. However, worn retreaded tires usually are discarded in a landfill. Approximately 10% of discarded automobile tires and 55—70% of tmck and bus tires are retreaded (55). 

Tire disposal costs are 0.10—3.00 per tire. Cost for incineration without heat recovery is 0.35—0.70 per tire. Transportation of discarded tires can cost 0.04/kg, and size reduction can cost 0.20—0.60/kg. Distribution of passenger car tires is landfill, 85% retreaded, 10% and reclaimed, burned for fuel, and spht, 5%. 

In addition to the soHd form of natural mbber it is available as a soHd suspended in water, known as latex. Synthetic mbbers are also available in latex form. Latex has become an important commodity used in the manufacture of dipped goods for health and disease protection. The principal uses of natural mbber are as follows tires and retreading, 70% latex (gloves, balloons), 12% mechanical goods, 9% load-bearing components, 4% and other, 5%. 

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