California may mandate replacement-tire efficiency standards


California is considering efficiency standards for replacement tires, helping ensure that hybrids and electric cars sold with efficiency-focused tires would consistently get comparable replacements.

As noted by trade publication Modern Tire Dealer, replacement-tire efficiency standards have been discussed for some time, but may be moving closer implementation following data gathered by the California Energy Commission (CEC), the regulatory agency in charge of drafting proposed standards.

The CEC was previously granted authority to adopt and implement tire-efficiency standards via legislation, and it launched the data-gathering campaign in November 2020. Earlier this month it recommended a minimum standard for rolling resistance, along with a rating system aimed at helping consumer compare the relative efficiency of replacement tires.

Relative cost effectiveness of various tire rolling resistance efficiencies (via CEC)

Relative cost effectiveness of various tire rolling resistance efficiencies (via CEC)

The minimum standard would be a rolling resistance coefficient of 9.0, which the CEC says is a current industry benchmark, that would apply to the sale of new replacement tires beginning January 1, 2026. A more stringent target of 7.0 would take effect January 1, 2028. These targets wouldn’t be allowed to interfere with wet-traction or other safety standards, according to the CEC.

The CEC also proposes a rating system for replacement tires, of one to five stars, with five being the most energy efficient and representing the highest potential cost savings. Although low-rolling-resistance tires can cost more, California also says: “Consumers may save between $800 and $1,400 per set of four replacement tires over the life of the tires through increased efficiency savings.”

2021 Ford Mustang Mach-E

2021 Ford Mustang Mach-E

California has committed to ban sales of new gasoline cars (other than very efficient plug-in hybrids) by 2035, and these standards could help support that goal.

Tires and wheels can have a huge effect on EV range, which is why most EVs leave the factory with efficiency-focused low rolling-resistance tires. EVs do also need different tires, for a number of reasons like added weight and the need to mask tire noise that would otherwise be muffled by a combustion engine, so ensuring like replacements are available will be important.

A group of automakers is backing California in a legal challenge against the state’s emissions authority, so maybe they’ll back these tire standards as well.

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