California adopts new rolling-resistance standards for replacement tires

The California Energy Commission voted unanimously to require that most replacement tires sold in the state meet rolling-resistance limits equal to those of original-equipment tires. The rule, which will take effect in two phases, sets a maximum rolling-resistance level of 9.1 newtons per kilonewton (N/kN) for tires sold beginning in 2029 and tightens the limit to 7.2 N/kN in 2033. According to the commission, about 70 % of tires currently on the market do not meet the new standards.

The regulation includes exemptions for used tires, competition tires, snow tires, motorcycle tires and certain off-road tires limited to 99 mph. The commission estimates the incremental cost to consumers will be $1.50 per tire during the first phase and $6.50 per tire during the second phase, while a typical gasoline-car driver could save roughly $179 in fuel over the life of a tire set, based on a gasoline price of $4.60 per gallon.

"In short, these proposed regulations will not result in a shorter replacement tire lifespan for California drivers," the commission said in a statement, adding that testing with an independent laboratory found no relationship between efficiency and treadwear in the California market.

Goodyear expressed concerns about the cost impact. Bret Gladfelty, speaking for the company, told the commission that the rules could raise consumer costs and that technical and legal issues remained unresolved. In a letter to the commission, Gladfelty questioned the agency’s cost estimates, suggesting that price increases could reach several hundred dollars per tire.

The rule also introduces a voluntary “leaf” rating system to indicate tire efficiency, similar to existing energy-efficiency labels. Manufacturers may choose whether to display the rating, and consumers can verify a tire’s rating through an online database maintained by the state.

Other states, including Washington and Rhode Island, are reportedly reviewing the California standards as a possible model for their own regulations.