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products Tires/Wheels

A PSI Worth of Prevention …

Posted: August 1, 2014 by Jim Park

It’s a good thing that we have crash-test dummies. To illustrate the destructive power of an inflated truck tire, a British-produced safety video posted on YouTube shows a crash-test-dummy tire technician perched on an inflating tire as it explodes.

The event launched the tire and the dummy (minus a leg and possibly an arm) 20 feet into the air. If lift-off didn’t do enough damage, upon its return to earth, the tire/rim assembly landed squarely in the middle of the test-dummy’s chest.

The near-instantaneous release of 1,650 liters of air compressed to eight or nine times normal atmospheric pressure packs a heck of a punch. According to the Tire Industry Association, there’s enough energy in a 11R22.5 tire inflated to 100 psi to hurl a 16-lb bowling ball three-quarters of a mile. 

Still, it’s not uncommon to see people standing beside an uncaged tire while inflating it. You probably won’t see that happen in most of Canada’s better tire shops, but at some fleets where the dispatcher doubles as the tire technician and the janitor, and in little out-of-the-way off-the-radar places where they continue to do things they way they always have, it still happens.

To prevent damage and injury resulting from improper handling of tires, the U.S. Occupational Safety and Health Administration (OSHA) developed regulation 29 CFR 1910.177, requiring employers to provide proper tire handling training for all shop personnel doing tire maintenance and service. The regulation also features lists of equipment and facilities required to do the work safely. With the exception of Ontario, there are no specific Canadian tire service regulations. 

Sean Doyle, general manager of the Kal Tire outlet in Stoney Creek, Ont., says Canadian tire repairers follow the OSHA rules, but because the "rules" are American, they have no force in this country.

In the case of a stubborn tire, some
techs use a device called a Cheetah to get
the bead to seat, says Kal Tire’s Atkinson.

"Until Ontario came up with a definitive tire and wheel installer program in the late 1990s, we had nothing more than the OSHA rules to go by," Doyle says. "Other provinces in Canada still use the OSHA guidelines, but the enforcement component is obviously missing."

Ontario’s Commercial Vehicle Wheel Service Training program was implemented in 1996, mostly in response to a rash of wheel-off incidents that resulted in two fatalities, but it does contain specific rules and procedures relevant to tire and wheel removal, service, and installation. 

In addition to the OSHA requirements, the Tire Industry Association and the major tire manufacturers have developed safe tire handling procedures and training programs for employers and workers. The tire technician’s world is a safer place because of the regs, but some fleets and tire shops are still servicing tires the old way.

Kal Tire, for example, has developed its own program — a hybrid of the Ontario program, OSHA rules, and other best practices. Even the locations outside Ontario follow the guidelines.

"All the training we do is signed-off on by the trainers and the techs, and it’s all documented," Doyle says. "From a liability standpoint, this is a necessity, but from a practical point of view, we just won’t have anyone on our staff doing this kind of work in an unsafe manner. It’s not worth it."

Todd Labbe, the "Metro Manager" of a Wingfoot Commercial Tire outlet in Brunswick, Ohio, says safety is the first priority at his shop, even before customer service. 

"It can be a dangerous job, and that’s why we have all the OSHA programs in place as well as a number of our own, developed by Goodyear and the TIA," he says. "We have a number of zero-tolerance items on our safety check lists that carry immediate dismissal warnings. On top of that we have all the proper tools and equipment, and we use them the way they were intended — even if that slows the process down."

Risks & Responsibilities:

There is also some specific equipment required — not just by OSHA, but by common sense — before one starts working on truck tires.

OSHA demands that all tires be inflated to working pressure inside a safety cage designed to withstand the force of an exploding tire.

Cages should not be bolted to the floor in case the force of an exploding tire shears off the bolts and makes projectiles out of them, too. Multiple tire cages should be three to five feet from each other, and tire cages should be inspected before use for damage or wear that might decrease its effectiveness.

It should be noted that bolting the wheel back on to the truck prior to re-inflation is not a suitable substitute for a tire cage. The wheel hub will restrain the wheel in the event of a rapid pressure loss, but it will not prevent debris from flying outward from the tire. This practice may also cause considerable damage to the body and possibly the chassis of the vehicle.

Popping sounds mean sidewall cables of a tire
are breaking, signaling a zipper rupture is imminent.

When inflating a truck tire, OSHA requires clip-on air chucks, not chucks threaded to the valve stem, and there must be a pressure regulator/relief valve accessible to the technician inflating the tire.

Following the application of an approved lubricant to both the rim and the bead surface, and seating of the tire on the rim, inflating the tire to 5 psi is permitted outside the tire cage. In most cases, a properly prepared rim and tire will generally mount using air pressure fed just through the valve stem — but not always. If not, use only an approved device such as a Cheetah to help seat the bead to the rim.

Doug Jones, customer engineering support manager for Michelin Americas Truck Tires Tire recommends seating the bead with the tire in a horizontal position to ensure concentricity of the bead on
the rim. 

"This process should never be done in a vertical position. Doing so will often result in beads that are not centered on the rim, due to the weight of the wheel," Jones says. "This will lead to lateral run-out which can cause a vibration or irregular tread wear."

With the beat seated and the tire inflated to no more than 5 psi, move it to the tire cage, remove the valve core, and connect the clip-on air chuck, and inflate the tire to 20 psi, Jones advises.

"Technicians should inspect the tire after inflating it to 20 psi," says Jones. "Bulges in the sidewall often indicate the beginning of a zipper rupture. During inflation, technicians should also listen for popping sounds, which are sidewall cables breaking, signaling that a zipper rupture is imminent."

The critical element in the re-installation process is getting the proper torque on the wheel fasteners in the proper sequence.

The final piece of a safe and proper wheel installation is re-torquing of the wheel after 100 to 150 km of driving.

This is almost universally ignored, but Doyle says it is absolutely vital that the wheel be checked once it has been returned to service.

"Only about one-third of the better fleets in Canada do this regularly," he says. "I’m aware of one Canadian private fleet that spends about $8,000 a month on re-torques. The drivers will pull over 150 km down the road following a repair and call a service truck to come out and re-torque the wheel. It’s hugely expensive, but I have to admire them for putting safety ahead of cost."

Like everything in life, there’s an easy way to service tires, and a right way. Doing it right may take a little more time, and cost a little more money, but there’s no excuse for endangering life in the pursuit of savings.

We’ve heard of tire techs being launched 50 ft across a room by an exploding tire, and we’ve seen people killed on roadways because of improper service practices. Those are events best left to the crash-test dummies.

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