Tougher Fuel Standards Push Tiremakers to Cut Rolling Resistance Even More
It’s been five years since the National Highway Traffic Safety Administration adopted a second round of fuel efficiency standards for medium- and heavy-duty vehicles.
Despite shifting political winds, these next-generation greenhouse gas (GHG) emissions standards — commonly referred to as “GHG Phase 2” — have stayed in place. And they present ongoing challenges from a tire development standpoint.
Bill Walmsley, product category manager, line-haul and coach tires, long distance transportation, Michelin North America Inc., calls tires “a key input” to the enhanced regulations. “There are suggested levels of rolling resistance coefficients that vary, depending on the class and type of vehicle,” he says.
“The Environmental Protection Agency (EPA) provides a tool called the GEM model, which allows the (truck) OEM to enter the various inputs that contribute to GHG and then see the end result in terms of carbon dioxide. The key, with respect to tires, is to be able to provide a tire that not only provides a low rolling resistance coefficient for improved contribution” to carbon dioxide reduction, but also still meets the vehicle manufacturer’s needs — “and ultimately, the end fleet that purchases the truck.”
“The challenge lies in balancing the performance triangle of rolling resistance, longevity and traction,” says Dave Johnston Sr., manager, commercial products and business development, Toyo Tire U.S.A. Corp.
“Traditionally, there were trade-offs to achieving success in all three areas. Today’s fleets expect a tire to be able to perform in a multitude of environments and still deliver a solid return on investment.”
“It all comes down to tire design,” says Marco Rabe, Continental Tire the Americas LLC’s head of research and development for truck tires in the Americas region. “If we’re targeting a tire with better fuel economy, then we utilize tread patterns and tread compounds that improve rolling resistance.
“In addition, tire designers always have the option to reduce tread depth to improve rolling resistance. However, this always comes at the cost of removal mileage. This trade-off will need to be managed as regulators force stricter fuel efficiency targets.”
It all adds up
“Typically, improvement in one area of tire performance - for instance, rolling resistance - often requires a trade-off in another area, such as tread wear or the tire’s lifecycle,” says Matt Schnedler, senior product manager, Bridgestone Americas Inc.
“The challenge then becomes utilizing this technology to improve the performance metric influencing the standard, while also maintaining or even improving other metrics customers have come to expect.”
Rick Phillips, CEO of Keter Tire Inc., says his company’s engineers focus on “several areas of development and design” in an effort to satisfy fuel efficiency requirements.
“Probably the most critical are casing construction, tread design, rubber compounding and the manufacturing process itself. We consider all of these areas and how they can best work together to achieve the EPA’s targets.”
Bob Loeser, truck tire engineer, Kumho Tire USA Inc., says that in addition to focusing on tread compounds and tread pattern modifications, Kumho is “starting to look at other components, like sidewalls and inner liners.”
Looking down the road, he says “it will be interesting” to see how the design and performance of electric trucks will influence tire design. “GHG standards are aimed at the entire truck, so no set tests are standard for each component that makes up the vehicle.”
What dealers need to know
What should tire dealers keep in mind when it comes to enhanced greenhouse gas emissions standards and tires that are designed to meet those requirements?
Bridgestone’s Schnedler says that “GHG is primarily an original equipment issue as the trucks must meet the guidelines when new.
“However, to better service their fleets, commercial tire dealers must be knowledgeable about low rolling resistance and/or SmartWay-approved tires when it is time for replacement. There are several options for replacement tires, but as mentioned before, there may be trade-offs that must be considered when meeting specific customer needs.”
“While GHG may not be at the forefront of all dealers’ minds, it is important to recognize that the fleets they serve have much interest in reducing” greenhouse gas emissions, says Rob Williams, vice president, TBR sales, Hankook Tire America Corp.
“The transportation industry will make it a priority to reduce these emissions and continue to create tighter standards, including improved fuel economy.”
“This is a hot topic, so dealers should make an e ort to be as informed as possible,” says Keter Tire’s Phillips.
Customer education is “especially relevant right now, given the current trend of fuel prices.”
“This will be the standard adopted by users,” says Joaquin Gonzalez Jr., president of Tire Group International, which markets Cosmo brand truck tires.
“It takes time for these norms to become part of the consumer ‘ask.’ But dealers must get ready to offer products that meet these demands.”
And don’t forget marketing. “Dealers would need to focus on advertising and promotion” of these tires, says Abhishek Bisht, assistant vice president, Americas, Apollo Tyres.