ZIPPER RUPTURE DEFINED: A zipper rupture is a circumferential rupture in the mid sidewall of a steel cord radial tire. Weakened steel cables in the tire's sidewall, caused by running underinflated or flat…defined as, a tire that carries less than 80% of proper inflation. The resulting rupture and air blast can explode with the force of as much as three quarters of a pound of dynamite, leaving a 10-36 inch gash in the sidewall that looks like a zipper. 

Below is a photo of an ideal Zipper Safecage, courtesy of TIA.

"...Zipper ruptures are not a tire design issue, but a maintenance issue. Running the tire under-inflated creates flex, which damages the tire, which causes the zipper problem."  

Al Cohn, Marketing Manager,
Goodyear Tire & Rubber

"Zippers are caused by radial truck tires run at or near zero pressure...There are no known materials to allow a (pneumatic) medium truck tire to carry its load at zero pressure."                

Randy Clark, VP of Marketing,
Michelin, Americas Truck Tires

Weakened steel cables in the tire's sidewall caused by running the tire flat or under-inflated are generally blamed with causing zipper-like ruptures--often accompanied by explosive force--in the sidewall of truck and light truck tires. The visual inspections, X-rays, ultrasound or other tests, which add to the danger, cannot always discover potential zipper problems.

Ultraseal International, Inc.
Modern Tire Dealer, April 1995

NEW! 

 "Zipper Failures Not Only Embarrassing"  By Peggy Fisher.  When a truck tire ruptures, results can be catastrophic----and deadly. Use every opportunity you can to remind and train your company's associates to prevent them. Their very lives may depend on it. (Reprinted from TIRE BUSINESS, October 13, 2003, and used with permission.)

Please take the time to download and read this excellent PDF.  Download PDF (809 KB)

"Armed and Still Dangerous" by Bob Ulrich, discusses how tire dealer awareness has resulted in fewer injuries, despite an increase in Zipper Ruptures.

The 2nd article, (a continuous part of the same pdf) is, "How To Be Zipper-Free!" by Ed Wagner, and it discusses how pressure-testing drastically limits Zipper Ruptures in radial tires. ( Reprinted from Modern Tire Dealer/MTD, April 2001, and used with permission) 

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"Identifying A Zipper Rupture" By Kevin Rohlwing. When radial tires operate at less than 80% of the recommended operating pressure, excessive sidewall flexing causes permanent damage to the steel body cords.   (Reprinted from Commercial Tire Service Update, November 2000 and is used with permission.)

Please take the time to download and read this excellent PDF.  Download PDF (1.79 MB)

"Zippers Can Happen to Anyone, Anywhere" By Kevin Rohlwing. "You may not be able to tell when a zipper will actually occur, but you can recognize the signs before it's too late."  (Reprinted from Commercial Tire Service Update, October 1996 and is used with permission.)  

Please take the time to download and read this excellent PDF.  Download PDF (1.2 MB)

Occupational Safety and Health Administration (OSHA) represents federal law for servicing truck tires and wheels. You cannot repair one flat radial truck tire on a dual assembly without inspecting the other. Both must be completely deflated before they can be removed from the vehicle, demounted and thoroughly inspected. Read entire article, "Can You Fix One Flat Tire?" (Reprinted from Commercial Tire Service Update, June 2002 and is used with permission.)   

Please take the time to download and read this excellent PDF.  Download PDF (1.79 MB)

 

TIA offers a 2 video set, on the handling of  Zipper Rupture to reduce the chances of  injury. E-mail: info@tireindustry.org

An illustrated article, "What is a Zipper Rupture?", is featured in the web site of Marvin Bozarth, http://www.tireanalysis.com

TRIB considers this an on-going topic and will continue to add information as it becomes available