The 1960s and '70s were turbulent periods-not only for our nation and my family, but for retreading as well.
While the retread plant population began the decade at well over 12,000, the number of plants began to dwindle. This decline was due to several factors:
* A trend toward larger facilities, resulting in retreader consolidation;
* Fiberglass-belted tires that presented high reject rates and many problems to the retreader;
* Radialization, which required the purchase of new and expensive radial design and dimension molds;
* Changing tire sizes;
* Government control and involvement; and
* An increase in liability litigation.
Due to the increased problems and costs associated with retreading, many passenger tire retreaders simply called it quits.
Truck tire retreading during the 1960s and 1970s remained virtually stagnant with the use of bias tires. However, in the late 1970s radial tires were introduced to the U.S. trucking industry, which changed the face of American retreading for years to come.
Radial truck tires were relatively expensive compared to bias truck tires. But tire manufacturers promised that they could be retreaded several times, which in the long run made them more economical than bias tires. As a result the trucking industry began the conversion to radials.
Retreaders found that a smaller investment could be made in precure retread processes to retread the unforgiving radial tire dimensions, as opposed to purchasing relatively expensive and dimensionally restrictive full circle or segmented molds. As a result, the retreading industry-which had been predominantly mold cure since as far back as my mother can remember-became dominated with precure retreaders.
Bandag remained the leader, but almost all of the other tread rubber manufacturers entered precure tread manufacturing as well. Mold manufacturers declined.
By 1979 tire retread plant population in the U.S. had dropped to 3,400.
Tire retreading in the 1980s really began to embrace globalization. European companies began marketing equipment and techniques in the U.S. Italian companies like Marangoni S.p.A., Cima Impianti S.p.A., Europress and CISAP S.p.A. introduced presses, buffers, molds and extruders. Collman GmbH from Germany and SIO A.p.S. from Denmark brought over buffers and the English company Barwell International Ltd. introduced a new type of extruder. All of these efforts were focused primarily on truck tire retreading.
Non-destructive inspection (NDI) machines first appeared in the 1980s. Bandag introduced its NDI machine and before long other retread companies came out with their ``high-tech'' inspection equipment that used ultra-sound, holography and high pressure. This equipment was really needed since the new radial truck tires were plagued with separation problems that would otherwise go undetected.
Passenger tire retreading, for the most part, met its death in this decade. In 1980 some 25 million passenger tire retreads were sold. By 1990 this number had dropped to 13 million. While mud and snow tires had always been a mainstay of passenger tire retreaders, their numbers declined due to the appearance of all season tires as original equipment on vehicles and in the aftermarket.
The final deathblow came from the other side of the world as low-cost European and Chinese tires entered the U.S. market. To compete, retreaders reduced the quality of their products to make them cheaper. Their performance worsened, and some retreaders believe passenger retreads eventually died in disgrace.
By 1989, the number of retread plants in the U.S. dropped to 2,100.
The 1990s and the New Millennium ushered in the era of ``high-tech,'' computer-controlled retread equipment. Goodyear introduced its UniCircle process and Marangoni brought its Ringtread technology from Italy in which the precured treads are made in spliceless circles that are stretched around the casings by special building machines. Bridgestone/Firestone opened its Oncor mold cure plant in St. Louis for the mass production of retreaded truck tires.
Non-destructive casing inspection technology is really credited with improving retread quality during this period. Ultrasound was greatly improved and X-ray became available to retreaders. Shearography was the new and improved offspring of holography, and it gave birth to differometry, which is specifically designed for high-speed production and testing.
Computer controlled buffing technology made its debut at this time. This technology results in more precise roundness and consistency of the prepared casing and has greatly improved retread performance. Also introduced were computer-controlled builders and extruders that apply treads without stretching the splice and build to precise dimensions. This equipment also reduces labor and improves quality.
In addition, state-of-the-art compounding produces treads that last longer, run cooler and have a higher resistance to irregular wear.
Today there are fewer than 850 retread plants producing well over 17 million retreaded truck tires-which is more than half the replacement truck tire demand. Although the number of plants has declined, the number of retreads produced annually at these facilities has increased dramatically to more than 19 million in 2003 from 16 million in 1982.
While my mom has seen a great deal of change in the past 94 years, I'm sure there's a great deal more to come as the retread industry continues to evolve with the times. What's ahead? Who knows? Like Forest Gump's mother said: ``Life is like a box of chocolates. You never know what you're going to get.''
For those of you getting older and worrying about it, take a lesson from my mom. She brags to everybody about how old she is. I think she wants people to know why she looks as she does. After all, she's traveled a long way and a lot of the roads weren't paved.