Is California really banning high-performance tires?

Betteridge’s law of headlines states that “any headline that ends in a question mark can be answered by the word no.” I run 200tw tires on a daily driver in California. So when the infographic started circulating claiming the state was banning high-performance tires, I admittedly got nerd sniped. So I actually gave Docket: 26-TIRE-01, the proposed terms, and the California Energy Commission’s (CEC) Economic Impact Analysis a read rather than take social media as truth. As a disclaimer upfront, IANAL

The viral post is partly right but significantly distorted for clicks. Here is the TL;DR:

Fact: California is proposing tire efficiency standards that, by 2031, some current high-performance tires will not meet without changes. And there’s still time for us enthusiasts to do something about it.

Also, fact:

• This is still a proposal and nothing has been ruled yet
• The rule regulates what can be sold new in California, not what you can own, drive, or import for personal use
• Ultra High Performance tires are explicitly given the most lenient targets of any tire category in the rule
• Genuinely low-volume tires can qualify for a production exemption
• A safety-valve exemption process exists for cases where no compliant tire is available for a given vehicle
• This has been coming since a law passed in 2003. Manufacturers have had 20+ years of notice, and the industry/SEMA is already organized against it

“Cup 2s will be banned” overstates both the certainty and the scope, and the rules are already structured to give performance tires more headroom than ordinary replacement tires.

Fair warning: what follows is a very long read. If you’re already on board with making sure Ultra High Performance tires can continue to exist and just want to do something, skip to the letter template and send the CEC an email. Public Comments close June 9th.

TL;DR: What is Actually Being Proposed?

The Replacement Tire Efficiency Program is a proposal by the California Energy Commission. It’s an energy efficiency standard to be applied to replacement tires sold in California. If the proposal becomes law, a tire that does not meet the rolling resistance threshold cannot legally be sold in the state of California after January 1, 2031. Tires you already own will not be affected. Tires manufactured before the compliance dates will not be affected. A tire mounted on a car driving in California will not be affected as enforcement is done by commercial regulation and not by law enforcement.

None of this is new, either. The legislation behind it, AB 844, passed back in 2003 and originally told the CEC to set tire efficiency standards by 2007. The agency paused for years while waiting on a federal NHTSA program that set test methods but never any actual standards, then restarted the effort in 2020. So tire manufacturers have had two decades of notice that this was coming. This cuts both ways. The big players have had plenty of runway to develop lower-RRC compounds, and the ones who care about the California market will either reformulate or push back through the rulemaking. This 2031 “deadline” is not the cliff the ChatGPT infographic makes it look like.

The standard is built around a tire’s measured EU-correlated Rolling Resistance Coefficient, or RRC, measured in newtons per kilonewton (N/kN). If you think this is a really weird unit, I thought so too. N is the rolling resistance force (read: energy loss) generated by the tire as it rolls down the road while kN is the load/downward force applied to the tire. So N/kN in actuality is unitless. What’s relevant is that lower RRC is better for fuel economy: less rolling resistance per downward force.

California didn’t invent this measurement and if you were paying attention you’ll note I mentioned the EU-correlated RRC. California is adopting the same RRC method underlying the EU tire label which has been mandatory in Europe since 2012. In fact, the EU label’s fuel-efficiency classes for passenger tires map directly to RRC bands: Class A is ≤ 6.5, B is 6.5-7.7, C is 7.7-9.0, D and E cover the higher-resistance bands above 9.0. Those exact Class A, B, and C breakpoints appear in the California rule as the thresholds for the new “leaf” ratings on California’s own labeling scale. That’s definitely not a coincidence.

There are two phase-in dates for the Replacement Tire Efficiency Program, and the difference is pretty significant.

Phase 1: January 1, 2028. The CEC’s own economic impact assessment study (CEC-600-2026-001, the SRIA) projects 100% compliance by 2028 at roughly $1.50 per tire in incremental cost. The $1.50 is a figure borrowed from a federal government (NHTSA) cost model that estimates what it costs to make a generic average tire slightly more efficient.

Phase 2: January 1, 2031. Only 90% compliance is projected because the threshold is tight enough that 91% of current passenger tires would fail it without reformulation. The SRIA puts incremental cost at roughly $6.50 per tire. This is, again, the same federal average-tire model and not a calculation of what it would actually cost to reformulate a Cup 2 or an A052 if that were even possible. For our beloved high-performance tires, 2031 is when we might have to worry.

The framing in most viral posts is a “ban of all aftermarket tires” (come on, Car and Driver, really?) and the infographic that is going around says “effective 2028”. The state’s own analysis says the 2028 step is near-painless. 2028 is mostly paperwork and the real concern comes about in 2031.

A Possible Misunderstanding

Dig into the proposed terms and the devil is in the carve-outs. The rule creates several tire categories with separate thresholds. “Standard” replacement tires face the tightest “Phase 2” cap at 7.1. Ultra High Performance (UHP) tires get a more lenient cap of 8.5 in 2031. The definition of UHP tires and the RRC gap between Standard and UHP is fairly significant. The CEC defines a UHP tire as one with:

1. W or Y Speed Rating (including the bracketed variants), meaning sustained capability of at least 168 mph, and
2. A relative wet grip braking performance index of at least 1.45

The wet grip braking performance index isn’t an absolute grip number. The tire under test is compared to a standard reference tire under the same wet conditions, and the index is performance of the tire under test divided by reference performance. An index of 1.0 means the tire grips in the wet exactly as well as the reference. An index of 1.45, the UHP threshold, means it stops about 45% shorter than that reference in the wet. Below 1.0 means worse.

That reframes the problem for some track tires. A tire can be enormously grippy in the dry and still post a mediocre wet index, because the compounds and tread voids optimized for dry or track use don’t necessarily translate to 45%-better-than-reference wet braking. If such a tire comes in under 1.45, it would fail to qualify as UHP and get judged against the stricter standard caps instead. The EU Wet grip label class (A through E) comes from a similar wet-braking measurement but it isn’t the same test, so a class C or class A EU label doesn’t map directly to a value you can compare against the 1.45 UHP bar. Because the index isn’t published in the US and the EU label class doesn’t translate cleanly to it, we genuinely can’t say today how many tires this affects or which specific ones fall short.

That’s where the real risk is. A tire that doesn’t clear the 1.45 wet grip bar would face an RRC cap of 7.1 in 2031 rather than 8.5. To put that in terms of the EU fuel-efficiency bands we do know: 7.1 sits squarely in Class B territory, while 8.5 is at the top of Class C. Whether the tires enthusiasts are most worried about would face that stricter cap is still unknown.

The CEC’s SRIA acknowledged this gap directly. UHP, long-life, and other specialty categories were “aggregated in with otherwise standard tires” in the economic analysis. The agency never separately quantified the cost or the benefit of applying this rule to UHP tires as their own category. The cost-benefit case that justifies the whole rule was built without isolating the segment we enthusiasts care about.

Banned vs. Safe

If you have seen the two lists going around on social media, there is a set of “banned” vs. “won’t be banned” tires. You might wonder where the data for both lists came from. Your guess is as good as mine. The lists cite Docket 26-TIRE-01, but when this Taiwanese-American went looking for his favorite Taiwanese tire brand, Nankang does not appear anywhere in the CEC’s documents. Looking at the two lists side by side might give you a guess as to what the inputs were. The “banned” five (Cup 2, RE-71RS, A052, R888R, CR-S) are all Extreme Performance Summer tires. The “won’t be banned” five (PS4S, ExtremeContact Sport, Potenza Sport, PZ4, Eagle F1 Asymmetric 6) are all Max Performance Summer tires. So someone sorted by performance category and called it a regulatory analysis.

Treadwear is not what the regulation measures, it has no bearing on a tire’s RRC, and it does not appear anywhere in Docket 26-TIRE-01. It’s a reasonable intuition since grippier tires probably roll with more resistance, but intuition is not data as we’ll show in the table below. The proposed regulation judges tires on the EU-correlated rolling resistance coefficient measured under ISO 28580 at an aligned reference lab. That number is not something tire manufacturers publish in the US. There is no US labeling requirement that puts a value on a spec sheet, a sidewall, or a regulatory database. So for any track tire you care about, the precise number is generally not publicly available today.

That’s the obstacle for anyone trying to make a fact-based argument about specific tires. You can’t prove it will be “banned”. The best available proxies are EU label classes and independent lab measurements, and both have hard limits. The EU label gives a letter band, not a number. An EU Class C tire has an RRC somewhere between 7.7 and 9.0, and you can’t tell from the letter whether it’s 8.4 or 8.6 when the 2031 threshold is proposed to be 8.5. On top of that, some models sold in the US are not sold in the EU, so no label exists for the exact product. For the models that do have EU labels, RRC varies by size within the same product line, so a verdict on one size doesn’t hold across even the “same” tire. I used both proxies for the table below and called out where the data is mixed.

Here are the actual caps a tire must come in at or below under the proposed rules. The rules only apply to tires manufactured on or after January 1, 2028.

As you can see, the Ultra High Performance category is the most lenient: 9.8 in 2028 then 8.5 in 2031, versus 9.0 then 7.1 for “standard” replacement tires. If a tire qualifies under more than one category, the most lenient (numerically highest) cap wins. Here is what the data actually shows for the tires on that viral list:

Three things stand out in that table:

• The Michelin Pilot Sport 4S, which appears on the “won’t be banned” lists, has many sizes with a Class D fuel efficiency label, which puts them at risk in 2031. Even some seemingly safer tires like the Bridgestone Potenza Sport have Class D labels as well.
• The measurements above are class bands and values can vary pretty significantly by size within the same model. Nobody can actually confirm what is being banned and what is “safe”.
• Someone used the RE-71RS and not the new RZ, and then lumped in the Goodyear Eagle F1 Asymmetric 6 against the Pilot Sport 4S. Surely they weren’t digging into EU labels.

Rule Exemptions

Careful readers will note two exemptions exist in the rule that could possibly “save” our beloved tires. Unfortunately, neither is a realistic path for the high-performance tires most enthusiasts actually buy.

Limited Production Exemption. A tire model qualifies if it has been manufactured or imported at under 15,000 US units annually. This is not just the most recent year, but in the current year and every prior year since the model’s introduction. One year over the threshold disqualifies the model permanently. The threshold is measured per tire model across the entire US, so a rare size of a high-volume model still doesn’t qualify.

A Michelin Cup 2 that ships as OE on production sports cars across dozens of sizes cannot plausibly satisfy a 15,000-unit-every-year-since-launch threshold. Neither can most of the other tires people are concerned about. Genuinely boutique, low-volume competition compounds with very limited distribution might qualify or even force manufacturers to limit production. The exemption protects the rarest tires and leaves the popular ones at risk.

Last Resort Exemption. There is also a per-vehicle exemption that requires a 60-day agency review, and expires after seven years. This is not likely a workable path for keeping a mainstream tire available.

Get Involved

So now what? Public comments to the CEC Docket close June 9, 2026 and a public hearing is scheduled for June 10, 2026 at 10 a.m. Pacific.

Public comments can be submitted to docket@energy.ca.gov. Reference Docket: 26-TIRE-01 in the subject line. A specific, well-researched comment carries far more weight than a general “this is stupid” email. You also won’t be commenting into a void. SEMA, the trade group for the “Specialty Equipment” and aftermarket industry, is already lobbying against the proposal. They’ve commissioned polling (80% of respondents are concerned about rules that would raise tire costs by hundreds of dollars per set) and are pushing enthusiasts toward the June 10 hearing. An industry coalition arguing the broad cost case, plus a wave of specific individual comments on the UHP analysis gap, is a stronger combination than either alone. The agency weighs a hundred identical form letters about as much as one comment, so the personal and specific ones are where you add something SEMA can’t.

The agency is required to address substantive technical and economic comments in the final rule. The most productive angle might be what the agency’s own study admits. UHP tires were never analyzed as their own category. The cost-benefit justification for the rule was built on aggregated data that gloss over the performance segment, and the 2031 UHP standard has no separate feasibility analysis for tires that genuinely meet the full UHP definition.

Asking to weaken the overall standard is re-proposing an alternative the agency already reviewed and rejected. Asking for a separate, technically feasible standard for Ultra High Performance tires is a different request that the CEC’s own admissions leave room for. Here is a letter template you can adapt and send before the June 9th deadline:

Subject: Public Comment — Docket: 26-TIRE-01, Replacement Tire Efficiency Program

California Energy Commission Docket: 26-TIRE-01

To the Commission and Staff:

[Personalize: I am a California driver / enthusiast / small tire-shop owner in (city). Add one sentence on why this matters to you.]

I support the program’s goal of increasing efficiency of the everyday replacement tires most Californians buy. My concern is specific: the proposed Phase 2 (2031) standards have not been adequately analyzed for their effect on ultra-high-performance tires, and the agency’s own economic record does not support applying the rule to that segment as written. I am asking the Commission to make a targeted change so that these tires remain available to California drivers.

1. The cost-benefit case never separately analyzed performance tires.

CEC-600-2026-001, p.4 states that low-load-index, long-life, ultra-long-life, and ultra-high-performance tires were “aggregated in with otherwise standard tires” in the economic analysis. The agency therefore never separately quantified the cost or the benefit of regulating the ultra-high-performance (UHP) segment. The incremental cost figures cited in the SRIA, approximately $1.50 per tire for Phase 1 and $6.50 per tire for Phase 2, were not derived by testing or modeling the performance tire segment. They are fleet-average estimates adapted from NHTSA rolling-resistance cost models for a generic baseline tire, then applied across the entire market. Because the UHP category was folded into that average rather than modeled on its own, the SRIA does not contain a cost estimate for what compliance would actually require of a high-performance compound. A cost-benefit case built on fleet-average numbers cannot support conclusions about a specific market segment that was never separately analyzed. I ask the Commission to conduct and publish a UHP-specific cost-benefit analysis before applying the 2031 standard to that category.

2. The UHP classification threshold creates an eligibility gap.

The §3302(58) definition of ultra-high-performance requires, among other criteria, a relative wet grip braking performance index of at least 1.45, measured per ISO 23671:2021. This index is not published by tire manufacturers in the United States and is not derivable from the EU label class. As a result, neither the agency nor the public can determine from currently available data which performance tires that exist in the market today actually qualify for the UHP category. Tires that do not clear the 1.45 threshold are not classified as UHP and would instead be judged against the stricter standard replacement tire caps. I ask the Commission to conduct and publish a UHP eligibility analysis for the tires most likely to be affected before Phase 2 takes effect.

3. The 2031 UHP cap lacks segment-specific feasibility analysis.

Even for tires that do qualify as UHP, the Phase 2 cap tightens from 9.8 to 8.5. The SRIA does not include feasibility analysis specific to the UHP category and models the fleet in aggregate. I urge the Commission to retain the 9.8 level for tires meeting the §3302(58) UHP definition beyond 2031, or to commission segment-specific feasibility analysis before the 8.5 cap takes effect.

4. The exemptions do not protect the performance tires people actually buy.

The limited-production exemption (under 15,000 U.S. units annually, and in every prior year) is measured per model across the entire U.S., so it shields only genuinely boutique, low-volume competition tires. Mainstream high-performance tires fitted as original equipment across dozens of sizes, such as the Michelin Pilot Sport Cup 2, cannot plausibly qualify. The last-resort exemption is reactive, per-vehicle, carries a 60-day review, and expires after seven years. Neither is a workable path for keeping the tires a vehicle shipped with available in California.

5. Keeping these tires available also protects California small businesses.

No tires are manufactured in California, and the SRIA estimates roughly 1,741 affected California small businesses bearing the rule’s compliance and training costs. When a popular performance tire is removed from the California market, those in-state shops lose the sale and the associated service work. The SRIA itself acknowledges that cross-border personal purchases are a likely behavioral response. The consumer is likely to purchase the tire out-of-state and the California shop gets nothing.

I ask the Commission to publish a UHP-specific eligibility and feasibility analysis before finalizing Phase 2 standards, and to establish a separate, technically grounded energy performance standard for tires meeting the ultra-high-performance definition, so that the program captures its intended fleet-wide fuel savings without removing high-performance tires from the California market.

Thank you for considering this comment.

Respectfully,

[Your name]

[City, California]

[Optional: Business Name / Affiliation]