Zipper failures in the sidewalls of steel-reinforced radial truck tires made headlines and stirred up an industry controversy in 1994. The subject of a public forum held in April by the American Retreaders' Association, zipper failures are explosive semi-circular-shaped sidewall ruptures that occur after a tire's steel radial cords become weakened and break, leaving a damage area that resembles an opened zipper-hence the name.
Dealers and manufacturers who took part in the gathering were sharply divided over what causes zipper failures and just how much of a safety problem they pose.
Dealers, observing that zippers didn't seem to be a problem until three or four years ago, said this points to some alleged change in tire construction as the primary cause.
Tire manufacturers, however, blamed underinflation, overloading and other forms of user abuse with causing zipper failures, which they described as extremely rare considering the number of tires in use.
Nevertheless, most participants at the Louisville meeting agreed that more needs to be known about zipper failures and what can be done to prevent such explosions from injuring workers and others.
As a result, ARA Executive Director Marvin Bozarth was asked to organize an industry task force, including both tire manufacturers and retreaders, to investigate the causes of zipper failures and recommend ways to reduce if not eliminate injuries resulting from them.
The 13-member task force, chaired by Mr. Bozarth, convened twice during the past year-in July and November-and was scheduled to meet again Jan. 6 in Miami.
He said the task force is working to prepare a wall chart telling how to identify zipper-prone tires and listing safety procedures for mounting, inflating and inspecting any steel-reinforced radial-including the light truck sizes, which presently aren't covered under the federally mandated procedures of the Occupational Safety and Health Administration.
Mr. Bozarth said the ARA is planning a similar open forum session for April 5, one day before its 1995 World Tire Conference & Exposition, which runs April 6-8, at the Kentucky Fair & Exposition Center in Louisville.
In addition to previewing the wall chart, attendees at the session will be shown a videotape featuring zipper failures staged inside and outside various types of safety cages.