Low rolling resistance needs to be kept in perspective
Tires are billboards for consumer information. And if you think the nomenclature is overbearing now, wait until the California Energy Commission (CEC) completes its fuel efficient tire program assignment.
It may be awhile, for there are still some bugs to be worked out. Ray Tuvell, program manager, recently hosted a staff workshop aimed at crystallizing Phase One of the program, which calls for the CEC to develop and adopt the following:
• “a database of the energy efficiency of a representative sample of replacement tires sold in the state,” and
• “a rating system for the energy efficiency of replacement tires that will enable consumers to make more informed decisions when purchasing tires for their vehicles.”
It is my understanding that once all three phases are complete, the program will be implemented nationally.
The CEC equates “energy efficiency” with rolling resistance because it can be measured. The more freely a tire rolls, the less energy it expends. The direct result is better gas mileage, which is why vehicle and tire manufacturers strive for low rolling resistance.
The CEC also is responsible for adopting test procedures that will measure rolling resistance as uniformly as possible. That is one of the reasons why Tuvell turned the workshop’s agenda over to the Rubber Manufacturers Association (RMA).
The tire manufacturers believe that IS0 28580 is the answer. According to the International Organization of Standardisation (ISO), the proposed standard “specifies methods for measuring rolling resistance, under controlled laboratory conditions, for new pneumatic tires designed primarily for use on passenger cars, trucks and buses.”
ISO 28580 also includes a method for correlating measurement results to allow for inter-laboratory comparisons. It should be approved by the end of the year.
However, because of lab-to-lab variations, the RMA also suggests a “five-star” rating system similar to other vehicle-related consumer information systems. The National Highway Traffic Safety Administration, for example, uses five-star safety ratings as part of its New Car Assessment Program, which rates vehicles to determine crash worthiness and rollover safety (see www.safercar.gov). Consumer Reports also rates products on a five-point system.
In addition, the RMA supports self-certification rather than data submission. UTQG (Uniform Tire Quality Grading) ratings for tread wear, traction and temperature resistance are self-certified. And those ratings are determined by tire manufacturers following strict government guidelines.
Mike Wischhusen, director of industry standards and government regulations for Michelin North America Inc., said a self-certified energy efficiency rating system would cost almost six times less than data submission-based reporting. In addition, it would involve less government intervention.
I was listening in on the workshop, and it didn’t seem like Tuvell was convinced. Or maybe he was just playing devil’s advocate. But I have talked with him in the past, and know he has been working hard to develop the best possible program.
Sometimes lost in the discussion is just how much of an effect tire rolling resistance has on fuel consumption.
Goodyear Tire & Rubber Co. recently announced that “the breakthrough tread compound in the new Fuel Max tires helps deliver 27% less rolling resistance than the original Assurance tires, which helps generate a 4% improvement in highway fuel economy for consumers.”
I don’t doubt the 27% decrease in rolling resistance between the tires. But the 4% improvement in fuel economy cannot be broadly applied because other factors may offset any noticeable savings. It’s true, but potentially misleading.
The weight and aerodynamic design of the vehicle affect a tire’s rolling resistance. So does the type of road surface.
Improper alignment and underinflated tires increase rolling resistance.
All these variables — and there are others — lessen the importance of measuring a tire’s rolling resistance. It’s nice to give a consumer comparative information, but it shouldn’t be cost-prohibitive to the tire manufacturer.
If the government standard is too unwieldy, nobody wins. If the manufacturer is not profitable, then prices will inevitably rise and brand options will decrease for both you and your customers.
Sure, the RMA has an agenda, but so what? Its solutions are reasonable.
The tire manufacturers are willing to add even more information to the sidewall. Given the circumstances, that should be enough. ■
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