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23 years ago, the California State Legislature passed a bill (AB 844) directing the California Energy Commission (CEC) to author and implement a new tire efficiency program. According to the CEC, the program’s stated mission 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.”
How’s that going so far, you ask? Well, it took Boston 16 years to complete the Big Dig. California needed seven more just to translate the above clause into the framework for a policy. This week, we’re finally finding out what the real-world implications of its rulings will be.
On spec, CEC’s argument is fairly straightforward: Automakers typically spec their cars with tires you simply can’t buy off the proverbial rack. Sure, the make and model name may be the same as what you see on your favorite car-part e-tailer, but automakers often request alterations to the finer details. Performance tires may have shallower tread than the generic models they’re based on to reduce squirm and make test-drivers feel more confident; the same can be done with efficient tires to reduce drag.
In some cases, automakers even specify entirely different tread compounds for their original equipment variations. And yes, one area that automakers tend to optimize for is fuel efficiency—often at the expense of tire longevity, advocates for the new rules argue.
Ever wonder why you didn’t get anywhere near the tread on your original tires as what manufacturers claim for replacement models? As we noted above, optimizing the tread for grip and/or efficiency can simply mean shaving down the tire’s tread—intentionally reducing its wear life, in other words. Consider that the next time you read customer reviews of original-equipment tires. Michelin, Goodyear, et al, may not necessarily be to blame for the poor longevity of factory rubber.
On the flip side of this equation, drivers often find that their replacement tires don’t perform as well at the fuel pump. Their new tires may end up lasting them longer, but those savings often go right back into the gas tank.
“Tire efficiency has a significant impact on the energy consumption of vehicles. How easily a tire rolls, referred to as rolling resistance, affects how much drivers spend on fuel for their vehicle, whether gasoline, diesel, electricity, or hydrogen fuel,” CEC’s summary says.
Ostensibly, California’s new rules will close this gap. Once this rule goes into effect in 2035, aftermarket tires will have to meet the same efficiency targets as their original-equipment equivalents. If you’re used to having your tires replaced at the dealership, this probably doesn’t seem like a big deal. Of course they have the original tires for your car, right?
“The regulations proposed in this staff report are, if adopted, expected to save each California driver of a gasoline passenger vehicle about $179 (2024 dollars) in fuel costs over the typical four-year life of a set of tires,” the summary says.
“In total,” it continues, “the regulations are anticipated to save California drivers about $979 million (2024 dollars) in fuel costs annually in 2035 and reduce greenhouse gas emissions by an estimated 2.0 million metric tons of carbon dioxide equivalent in 2035.”
That’s a little less than 2% of California’s total passenger fleet CO2 footprint.
Under the new rule, we’re likely to see tire manufacturers expand their offerings to include varying rolling resistances, much the same way we see tires specced for various load ratings today. Expect options for niche or limited-run models to be expensive, because hey, what choice will you have?
And speaking of choice, what about enthusiasts who actually want “worse” tires? Well, for starters, don’t panic. These new laws only govern what retailers are allowed to sell you, not what you’re allowed to do with your own car. And second, track and off-road groups were given the opportunity to weigh in on the new rules, and the CEC agreed to allow exemptions for ultra-low-treadwear track tires, though the regulations may pose challenges for high-performance summer tires that aren’t quite sticky enough to meet the threshold to be considered track equipment.
Critics are worried that forcing aftermarket tires to behave like OEM might ultimately hurt customers given how short-lived they tend to be, but the CEC is not convinced that this will be a limitation in the real world.
“The CEC staff analysis shows that the regulations proposed in this staff report are technically feasible, are cost-effective, and will not compromise safety, reduce tire life, or increase tire waste.”
The real impact will largely be felt by folks who simply get work done at dealerships as a matter of course. In that regimented environment, it will be tougher to skirt the rules. Plus, service departments stand to make fat margins on O.E. replacement tires. For dealers sweating the pivot to electric cars in California, anything that might encourage repeat service business is good news.
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Byron is an editor at The Drive with a keen eye for infrastructure, sales and regulatory stories.
