Notes ·
California's Efficient-Tire Rule Could Narrow What We Are Allowed to Buy
California has approved the nation's first efficiency standards for replacement tires.
The idea makes sense at first.
Tires with higher rolling resistance require more energy to move. California estimates that more efficient replacements could eventually save drivers almost $1 billion per year, reduce gasoline consumption by 141 million gallons annually and cut about 2 million metric tons of carbon dioxide emissions. The first efficiency standard begins in 2029, with a stricter one following in 2033.
The state is also adding a wet-grip requirement, which is important because efficiency cannot come at the expense of stopping performance. California law specifically requires the standards to be technically feasible, cost-effective and not adversely affect safety or average tire life.
But my immediate question was much simpler:
What happens when I want off-road tires on my truck?
The answer is not quite as reassuring as saying off-road tires are exempt.
California did create several exemptions. Tires with tread at least 18/32 inch deep are excluded. So are tires with a load index of 122 or greater, tires specifically made for off-road recreational vehicles and what the regulation calls a "large off-road tire."
But California defines that last category rather narrowly: at least 34.5 inches in diameter with a speed rating no higher than Q, or 99 mph.
That leaves an interesting gap.
A road-legal all-terrain tire used on a truck that is 31, 32 or 33 inches tall, has less than 18/32 inch tread and does not meet another exemption is still subject to the efficiency standard.
That does not mean California is going to inspect my truck and tell me I cannot install an all-terrain tire.
The regulation targets manufacturers, brand owners and tire retailers. Beginning with tires manufactured in 2029, they cannot sell a covered replacement tire in California if its rolling resistance exceeds the applicable limit.
So the practical restriction happens one step earlier:
The tire I want may simply stop being available for sale here if the manufacturer cannot or will not make it comply.
That is my concern with regulations like this.
The average commuter buying another set of ordinary tires may save some fuel and never notice anything changed. Someone choosing tires specifically for rocks, mud, snow, towing, durability or another specialized use may value characteristics that inherently conflict with minimizing rolling resistance.
The commission clearly heard that criticism. It expanded exemptions after feedback from tire manufacturers and automotive enthusiasts, including the new large off-road and competition-tire categories. CEC staff said it believes the exemptions cover the "vast majority" of tires principally designed for off-road use.
I am less convinced about the enormous middle ground of trucks and SUVs that spend most of their lives on pavement but are deliberately equipped to leave it.
There is also disagreement about cost. California estimates the standards will add about $6 per set initially and $26 per set under the stricter standard, with fuel savings exceeding that amount. SEMA cited an estimate putting the additional cost as high as $365.20. Those estimates are so far apart that the real-world market deserves watching once compliant tires actually arrive.
I like the idea of giving consumers an efficiency rating. Let me see rolling resistance alongside wet grip, tread life, load rating and everything else when I buy a tire.
I am less enthusiastic about deciding that efficiency should determine which otherwise legal tire I am allowed to buy.
For my truck, fuel economy is only one requirement.
Sometimes I am deliberately buying the tire that is worse at rolling down the freeway because it is better once the freeway ends.