Low Rolling Resistance Tires
Rolling resistance is the energy lost from drag and friction of a tire rolling over a surface. The phenomenon is complex, and nearly all operating conditions can affect the final outcome. With the exception of all-electric vehicles, it is estimated that 4%–11% of light-duty vehicle fuel consumption is used to overcome rolling resistance. All-electric passenger vehicles can use approximately 23% of their energy for this purpose. For heavy trucks, this quantity can be as high as 15%–30%. Installing low rolling resistance tires can improve fuel economy by about 3% for light-duty vehicles (LDVs) and more than 10% for heavy-duty vehicles (HDVs). In LDVs, a 10% decrease in rolling resistance can increase fuel economy by 1%–2%. It’s also important to ensure proper tire inflation.
New vs. Replacement Tires
New cars are generally equipped with low rolling resistance tires that offer better fuel economy. This helps the auto manufacturer meet their Corporate Average Fuel Economy (CAFE) standards. However, no requirements are currently placed on replacement tires. Therefore, if you want to purchase fuel-efficient replacement tires, you must research to figure out which tires have low rolling resistance.
Signed into law on December 4, 2015, the Fixing America’s Surface Transportation (FAST) Act requires the U.S. Department of Transportation, U.S. Environmental Protection Agency (EPA), and U.S. Department of Energy to develop regulations for passenger vehicle tire fuel efficiency standards. Some exemptions apply. Some exemptions apply. For more information, refer to Public Law 114-94.
Tires and fuel economy represent a significant cost in a fleet’s portfolio. In Class 8 trucks, approximately one-third of fuel efficiency comes from the rolling resistance of the tire. So, the opportunity for cost-effective energy savings from low rolling resistance tires in these and other vehicle applications is substantial. According to a North American Council for Freight Efficiency report, the use of low rolling resistance tires, in either a dual or a super-single configuration, is cost effective over the life of the vehicle. Essentially, this means the fuel savings pays for the additional cost of the low rolling resistance tires. In addition, advancements in tire tread life and traction will reduce the frequency of low rolling resistance tire replacement.