California’s new tire efficiency program is finally taking shape after years of development, with rules that would require aftermarket replacement tires to meet the same efficiency targets as their original-equipment counterparts beginning in 2035.

California’s Tire Efficiency Program Takes Shape

Three years ago, the California State Legislature passed AB 844, directing the California Energy Commission (CEC) to develop and implement a new tire efficiency program. The stated goal is to “ensure that replacement tires sold in the state are at least as energy efficient, on average, as tires sold in the state as original equipment on new passenger cars and light-duty trucks.”

The CEC has now outlined the real-world implications of the proposed regulations, which are designed to address differences between original-equipment tires and replacement tires.

Why Original-Equipment Tires Can Be Different

Automakers frequently specify tire configurations for new vehicles that differ from versions available as replacement products. Although the tire may carry the same make and model name, manufacturers can request changes to details such as tread design and compound.

Performance tires, for example, may use shallower tread to reduce squirm and improve driver confidence. Similar adjustments can be made to reduce rolling resistance and improve efficiency.

In some cases, automakers specify entirely different tread compounds for original-equipment tires. Advocates for the new rules argue that fuel efficiency is one factor manufacturers optimize, sometimes at the expense of tire longevity.

That can help explain why original tires sometimes do not deliver the tread life advertised for their replacement counterparts. Optimizing a tire for grip or efficiency can involve reducing tread depth, which can shorten its wear life.

Replacement Tires and Fuel Efficiency

The tradeoff can also work in the opposite direction. Drivers may find that replacement tires last longer but deliver worse fuel economy, potentially offsetting some of the benefit of their longer service life through increased fuel costs.

The CEC says tire efficiency has a significant effect on vehicle energy consumption. Rolling resistance influences how much energy a vehicle requires, affecting fuel costs for gasoline, diesel, electricity and hydrogen-powered vehicles.

What the Rules Would Mean for California Drivers

Under the proposed regulations, aftermarket tires would have to meet the same efficiency targets as their original-equipment equivalents once the rule takes effect in 2035.

The CEC estimates that the regulations would save each California driver of a gasoline passenger vehicle about $179 in fuel costs over the typical four-year life of a set of tires, measured in 2024 dollars.

Statewide, the regulations are anticipated to save California drivers about $979 million in fuel costs annually in 2035 while reducing greenhouse gas emissions by an estimated 2.0 million metric tons of carbon dioxide equivalent that year.

The projected reduction represents a little less than 2% of California’s total passenger fleet CO2 footprint.

More Tire Options Could Come With Higher Prices

The new requirements are expected to encourage tire manufacturers to expand their offerings across different rolling-resistance levels, similar to the way tires are available with different load ratings.

Niche or limited-run tire applications could become more expensive under the new framework, particularly where manufacturers need to offer specialized products to meet specific demands.

Track Tires Would Receive an Exemption

The regulations also address drivers who want tires designed for performance rather than maximum efficiency. The rules govern what retailers can sell, rather than what owners are permitted to do with their vehicles.

Track and off-road groups were given an opportunity to weigh in on the proposed regulations. The CEC agreed to allow exemptions for ultra-low-treadwear track tires, although the regulations could create challenges for high-performance summer tires that are not sticky enough to qualify as track equipment.

CEC Says Safety and Tire Life Will Not Be Compromised

Critics have raised concerns that requiring aftermarket tires to perform more like original-equipment tires could ultimately hurt customers, particularly because original-equipment tires can have relatively short service lives.

The CEC, however, does not expect the regulations to create those problems. Its staff analysis states that the proposed regulations are technically feasible, cost-effective and will not compromise safety, reduce tire life or increase tire waste.

Dealerships Could Feel the Biggest Impact

The biggest practical effects are expected to be felt by drivers who routinely have their vehicles serviced at dealerships. In that environment, it could be more difficult to avoid the new requirements.

Dealership service departments also stand to earn significant margins on original-equipment replacement tires. For dealers dealing with the shift toward electric cars in California, any development that could encourage repeat service business could be beneficial.

California’s proposed tire efficiency rules therefore represent a significant change for the aftermarket tire market, with the new requirements scheduled to take effect in 2035 and projected fuel-cost and emissions savings for drivers across the state.