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Tread freely

The U.S. Environmental Protection Agency (EPA) has established a verification program for retreaded tires used on Class 8 line-haul trucks. Once a retreaded tire receives EPA certification, fleets using those tires will be compliant with California Air Resources Board (CARB) regulations for low-rolling-resistance tires.

In a letter to tire manufacturers dated June 11, 2012, the EPA outlined testing procedures manufacturers of retreaded tires must use to demonstrate fuel efficient performance of their product.

The letter states that EPA will begin accepting applications for verification of retread products immediately.

According to EPA, “verified low-rolling-resistance retread products must provide reductions in fuel consumption of at least 3% as compared to the most popular retread products now in use.”

There are currently no retreaded tires on the list of SmartWay approved low-rolling-resistance, fuel-efficient tires. That changes with this announcement.

Several problems have historically stood in the way of retread certification. First, a retread is a two-part system. The question that arises is which to measure, the casing, the tread, or both. Tire manufacturers and retreaders have provided EPA with data on their retreads, but they often used different test methods. Left to sort the data out for itself, EPA concluded it needed better consistency across the tests and the results in order to make a decision.

Kyle Jensen, manager of industry and government relations at Bridgestone Bandag Tire Solutions, said that while measuring the rolling resistance contribution of the tread alone is difficult enough, measuring casings is equally complex.

“Each retreaded tire is a unique product because of the history of the casing,” he says. “Given its age, previous applications, etc., achieving rolling resistance values for each casing would not be easy.”

Without a precise definition of a retreaded tire in this context, the default position is that a SmartWay casing should be the basis for a SmartWay retread. That, however, would allow any tread — even a deep lug tread — to be used on a SmartWay casing, and thus be considered a SmartWay retread. That was clearly not the desired outcome.

Consistency in testing

A committee of tire manufacturers was formed in 2010 from within the Rubber Manufacturers Association (RMA) to develop a single test method and a reporting system.

Larry Tucker, marketing manager for commercial tires at Goodyear Tire & Rubber Co., and a member of the RMA committee examining this situation, said that EPA was looking for a way to define a tire that meets its greenhouse gas reduction objectives, and the industry stepped up to the plate to help.

“We had to decide on which test method, what wheel position, and what testing criteria would be needed to provide accurate data on rolling resistance by wheel position, by tread design, and by casing,” he said. “It will be our responsibility to give the EPA the data it needs to make informed decisions in setting the target values.”

The EPA letter describes the newly defined test casing as “an American-made Yokohama Super Steel RY-617 in size 295/75R22.5.” It will be used for all treads with conventional-width tires used in dual configuration. The test casing chosen was selected by the industry panel, the letter says.

The test protocol requires three new unused casings to be prepared for retreading in a normal manner, but tread curing must be conducted at the “worst case” (time and temperature) condition allowed by the manufacturer.

Additionally, for retreads used on single-wide tires, manufacturers may use an alternate casing made from a current EPA-verified new single-wide tire. The letter provided no additional detail on the single-wide test casing.

The test procedure allows results obtained from products with the same tread pattern (except fewer central tread rows and/or lugs) and rubber compound as a product verified with the test casing to be applied to the tread model sized for the single-wide casing.

Tests are to be conducted using a standard 8.25-inch test rim with the test tire turned against a two-meter drum (or a mathematical equivalent) using the ISO 28580 method at 85% of the maximum load rating of the tire. The resulting rolling resistance coefficient is recorded and reported in the manufacturer’s data submission to EPA.

EPA’s testing procedure opens the door to using retreaded tires on any casing — not just SmartWay approved casings — which will come as a huge relief to fleets operating 53-foot dry van trailers in California. Those fleets currently face a shortage of SmartWay casings, which could have required fleets to use virgin Smartway tires on all trailers operating in that state.

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Conti leads the pack

On June 12, 2012, the EPA said it would begin accepting applications for SmartWay verification of retread products.

That same day, Continental Tire the Americas LLC’s Commercial Vehicle Tire business unit submitted two retread tire products for verification as low rolling resistance technologies, under the U.S. Environmental Protection Agency’s SmartWay Transport Partnership’s new performance standards.

Continental’s HDL Eco Plus ContiTread (drive) and HTL Eco Plus ContiTread (trailer) were first presented to the EPA Technology Assessment Center in December 2011.

“Because of the adoption of these standards by the SmartWay Transport Partnership, the importance of manufacturing retreaded truck tires that perform just as well as the new products has been brought to the forefront of fleet owners and professional drivers across the U.S.,” said Paul Williams, executive vice president for truck tire, the Americas.

“Continental’s ContiTreads have always been made with the same standards and tread patterns as our new tires, which are the largest number of products verified by SmartWay today for low rolling resistance,” he said.

“Our submission of these ContiTread products for verification by SmartWay — as soon as the standards were published — is a testimonial to how committed Continental is to helping fleets lower their overall driving costs, over the entire life of their tires.”

According to the new standards provided by the EPA Technology Assessment Center, verified low rolling resistance products, when used on line-haul, Class 8 trucks, will provide reductions in fuel consumption of at least 3% compared to the most popular retread products now in use.

SmartWay is designed to promote creative approaches to reducing the energy and environmental impact of transport through a combination of strategies including more efficient tires, better aerodynamics, lower speeds, reduced idling, improved logistics, effective use of intermodal options, improved packaging, driver education and tire maintenance, among others.    ■

Yokohama and SmartWay: an active history

The U.S. Environmental Protection Agency (EPA) has designated Yokohama Tire Corp.’s RY617 commercial truck tire casing to establish a SmartWay verification program for retreaded tires used on Class 8 line-haul trucks.

Once a retreaded tire receives EPA certification, fleets using those tires will be compliant with California Air Resources Board (CARB) regulations for low rolling resistance tires.

Launched in 2004, the EPA’s SmartWay program identifies products and services that reduce transportation-related emissions, resulting in significant air quality and/or greenhouse gas improvements while maintaining or improving current levels of other emissions and/or pollutants.

“We are excited that the EPA has designated the RY617 steer and all-position tire for their verification program as the benchmark casing for retread technologies,” said Rick Phillips, Yokohama director of commercial sales.

“That means all retread solutions will be measured against a target number for rolling resistance on our casing. This is an important and necessary initiative by the EPA to incorporate retreading into the SmartWay program. It has been instrumental in helping the trucking industry become more fuel efficient and we are very glad to have our casing represent the benchmark.”

Yokohama has been active with the SmartWay program for many years, said Phillips. “We have seven commercial truck tires that have been added to the SmartWay list of verified technologies, meaning they are recognized as low rolling resistance tires.”

Jim Park is equipment editor  for Heavy Duty Trucking magazine, a sister publication of Modern Tire Dealer.

 

 

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