California Is Trying To Make Tires More EfficientAndi Hedrick (Andi Hedrick)"Hearst Magazines and Yahoo may earn commission or revenue on some items through these links."There are some new regulations brewing in the state of California that could have a real impact on the world of tires. It's called "California's Proposed Replacement Tire Efficiency Program," which is a rather scary phrase for any enthusiast who loves sticky high-performance rubber. Before you get too scared, though, this proposed regulation isn't law just yet. But its potential impact could potentially be considerable if it does make its way into the books.The California Energy Commission is behind this new proposal, and in short, it proposes rules that a replacement tire sold for a vehicle has to be at least as energy-efficient as the car's original equipment ones. California's primary motivation for this is to reduce fuel costs, fuel usage, and air pollution by way of more efficient tires. Phase 1 of the regulations going into effect would arrive in 2028, while an even tougher standard would start in 2031.AdvertisementAdvertisement"The cheapest gallon of gas is the one you never have to buy, and our proposed standard will save California drivers $1 billion of fuel every year," Ken Rider, chief policy advisor at the California Energy Commission, told Road & Track. "As [our] hearing showed, this standard has been developed through careful consultation with industry and rigorous review of real-world data on safety, tire lifespan, price, and other performance criteria. CEC is grateful for industry and other stakeholder feedback, both today and over the last five years. We are committed to further improving the proposal based on this feedback."Marc Urbano (Marc Urbano)If you're anything like us, you instantly have a million questions, most of them concerns over whether your favorite performance or track tires—which typically do not prioritize efficiency—would theoretically make the cut, or if they'd be banned for sale in California. Before we get to that point, there's a lot to understand about this proposal.For starters, California feels it needs to implement regulations for this because, as the CEC report put it, "tire manufacturers design and develop replacement tires that do not have the same emphasis on efficiency, which result in replacement tires that are, on average, less fuel-efficient than similar original equipment tires." This is true in many cases. Automakers want to report the best possible fuel economy and emissions figures, and one way to boost those numbers is by using more efficient tires with lower rolling resistance. Strategies to do so include tire compound technology, tread design, and even tread depth.The last one, tread depth, has been a point of contention with this proposal. For a performance car example, let's take the current Honda Civic Type R. The OE-specific Michelin Pilot Sport 4S tire on that car has a 9/32-inch tread depth; meanwhile, the non-OE Pilot Sport 4S in exactly the same size ships with 9.5/32-in of tread depth. That's small, but it's the kind of tweak you'll see all over the industry, as OEMs try to meet increasingly tougher emissions targets.The two different Michelin Pilot Sport 4S tire options for the Honda Civic Type RTire Rack (Tire Rack)This leads to a real concern with California's proposed new standards. If all replacement tires must meet or exceed the same efficiency numbers as OE-spec tires, one way tire manufacturers could go about meeting that ask is to simply ship tires with less tread. Of course, they would likely also push for more efficient compound technologies, and perhaps even improve efficiency enough that tread depth becomes less of an issue. The California Energy Commission claims that tire life won't be affected by its proposal, saying that the regulations must "not adversely affect the average tire life of replacement tires." (The commission even sent R&T a fact sheet on its testing processes, as an example as to why this regulation won't lead to tires with shorter lives.)AdvertisementAdvertisementAdditionally, CEC claimed that third-party tire testing commissioned for these regulations "did not reveal a clear relationship between tire efficiency and tire life." The report added that "to ensure that manufacturers continue to maintain or increase tire life, the proposed regulations allow long- and ultra-long-life tires to meet a less stringent energy performance standard. Therefore, the regulations proposed in this staff report do not reduce tire life and do not increase tire waste."Is that wishful thinking? That's hard to say from here. Also, those "long- and ultra-long-life" tires are rare birds, as California defines them as 1000+ or 1400+ UTQG-rated or higher. The same report makes the claim that 2 percent of tires have a UTQG rating above 600, suggesting there will be few-to-no tires allowed to meet a less-stringent efficiency rating.McLaren (McLaren)There are a few other exceptions listed concerning these regs. Key ones include winter tires, certain off-road tires, space-saver spares, motorcycle tires, tires with an exceedingly high load index, and tires for 12-inch wheels or smaller. Additionally, "limited production" tires that are produced or imported into the U.S. in quantities fewer than 15,000 during any calendar year would also be exempt.For many folks, that could be the saving grace for the tires you want to buy, but it's hard to say with all of this still in proposal form. A public forum held on June 10 allowed comment from the industry and members of the public; there was an outpouring of support from many organizations during the call, and tire companies themselves even called in to provide comment.AdvertisementAdvertisementRussell Shepard, director of technical communications for Michelin North America, spoke positively of the regulation, but still didn't fully endorse it. "Improvements in rolling resistance must be balanced with essential safety performances, such as wet traction, as well as other environmental factors, such as wear life and durability," Shepard said.Road & Track asked Bridgestone what it thought of this proposal, and a spokesperson for the tire company replied with the following: "Bridgestone supports the sustainability goals of California's Proposed Replacement Tire Efficiency Program. The company is working with the California Energy Commission to ensure that customers continue to have the safest, most efficient tire options for their vehicles." Continental, meanwhile, expressed doubts about California's ability to enforce the standards and ensure every tire sold in the state is compliant, and also raised concerns about track-specific tires and how they would be treated under these regulations.Meanwhile, the Specialty Equipment Market Association, a.k.a. SEMA, is unsurprisingly against this proposal. It published a whole article opposing the California Energy Commission plan, arguing it would "limit consumer choice and increase upfront costs." It also said Goodyear "and a coalition of industry stakeholders" have urged officials to halt the proposal, noting "increased replacement frequency" concerns and "unresolved safety and performance questions."The Energy Commission's studies for this proposal claimed to find no adverse effects to tire safety, noting "no relationship between tire efficiency and wet grip" and "no relationship between tire efficiency and dry traction." Those are some rather interesting conclusions, given how much of a difference changing tires can make to performance. Whether the criteria be braking distances, lateral grip or lap time on a racetrack, instrumented testing from Hearst Autos has shown time and again how different rubber on the same car can make big differences in performance.AdvertisementAdvertisementTracy Norberg, vice-president and general counsel of the U.S. Tire Manufacturers Association, took time to address the concerns of those who frequent track days with low-treadwear track tires on their vehicles. "We also recommend excluding street-legal race tires [from the proposal], which are not designed for sustained road use," Norberg said.Several other members of the public raised concerns over whether or not they would be allowed to buy tires for competitions or simply for open track days. Many of these competitions prescribe a certain treadwear rating, and they prioritize grip and heat capacity far and above rolling resistance. The CEC hasn't explicitly addressed these tires yet in its proposal, so their fate is currently unclear.Marc Urbano (Marc Urbano)One of the last angles I'll touch on is that California's measure seeks to establish a standard for consumers to easily read and tell how efficient the tires they're buying are. You'll see mileage warranties, UTQG ratings, and generic claims of eco-focused branding, but there's no way to directly compare efficiency and rolling resistance when shopping different tire models. California suggests a leaf system that corresponds to a range of rolling resistance coefficients. The more leaf symbols paired with the tire, the more efficient it is.This sure seems like a sound and fair way of informing consumers about what they're buying. Whether or not the tires you want to buy will still be available with these regulations is the question we'd still like answers to. Keep an eye on this one if you're in California.You Might Also LikeIf You Can Only Own One Car, Make It One of TheseThese Are the Most Popular Cars by State