There are basically three major trade-off when it comes to tire compounds: rolling resistance, traction, and tire wear. You can pick 2 of the 3.

When you shop for tires, manufacturers will try to make this eminently clear in the marketing - you pay a premium for tires that maximize on one or two of these features.

The changes that California is proposing basically means you are going to have to choose between traction and tire wear when shopping. Either super slippery tires, or tires that wear out quickly (hence why manufacturers are potentially behind the proposal).

> The rule also comes with exemptions including snow tires and those used in competition. All-weather tires are also excluded, but the state will track them, as that growing segment may be regulated in the future.

All-Weathers are excluded! Realistically this is a program that would only be effective in California.

Yes, there are trade-offs, but you can get really great tires on all three. The Michelin CrossClimate2 tires are arguably the best traction tires, Consumer Reports estimates 95,000 miles of tread life in their testing (higher than basically anything else), and they got a 4/5 for rolling resistance on Consumer Reports' dynamometer testing.

There's a lot of tires that are poorly made and just bad tires. For example, one tire got 2/5 for rolling resistance, tested to 55,000 miles for tread, and 2/5 and 3/5 ratings for the traction categories like wet braking, snow traction, ice braking.

I'm not arguing that there aren't trade-offs, but tire companies have been working to make better tires that minimize the trade-offs and produce better tires on all three.

> The rule is “designed 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.”

It sounds like the rule isn't exactly that strict. This (combined with the fact that all season tires aren't covered) presents a very low bar. But there are tires that are just garbage - they're bad at all three. It doesn't sound like this rule would impact good tires that have very long tread life and amazing traction. It sounds like it'd impact the tires that are a pile of garbage.

There's a difference between a tire that trades off a small portion of rolling resistance for traction and tire wear and tires that are poorly made and are trading off a huge amount of one or two of those categories because they're just bad tires.

If they're looking to improve tire energy efficiency with regulation, shouldn't they also make it a citable offense to drive with tires inflated below 30psi? You could probably even train a ML algorithm to recognize images of vehicles with underinflated tires, and send the driver a reminder!

Hmm, I have these tires on my Model 3: https://www.contimediacenter.com/eulabel/en/03143300000/

After 15,000 km, they haven't worn down by 2 mm. And that's despite being an EV. I think it really depends on how you drive.

I wonder if better rolling resistance + decent safe traction means more tire particulate pollution.

There are trade-offs, but there huge differences in quality between say a Michelin or Pirelli and a cheap Chinese brand.

Either super slippery tires, or tires that wear out quickly

Is it really not possible to get moderately-slippery tires that wear out moderately quickly, or is this just the hyperbolic writing style that infests the internet?

Yeah, it's a weird move to legislate this kind of trade-off, especially when one of the competing factors is tire wear. Making new tires takes energy too! If I was paranoid, I'd say the tire lobby was involved here and looking for an excuse to sell more lower durability tires.

Only Californians could dream up a stupid program like this and pretend that it's environmentally protective to send a ton more tire particles into the ecosystem, while costing consumers more, and probably increasing their carbon footprint at the manufacturing level, just to get shitty tires that might make a car a tiny bit more efficient.

I had a set of these low-rolling-resistance tires stock on an early FWD EV I had a few years ago and they were not only trash in terms of getting grip whenever there was even a hint of rain, but they also had awful stopping distance. Swapping them out for a set of all-weathers vastly improved everything about the car.

Consider the carbon footprint impact of a vehicle accident that totals both cars (never mind the human impact of this!). Probably cancels out hundreds of cars worth of carbon savings from using these shitty tires. Avoiding vehicle accidents has to be job one and tires are the single greatest factor in your stopping distance that you can simply buy an upgrade on. Combined with automatic braking technology - a great addition - you can seriously change the course of your life with a set that's only a couple hundred bucks more (in the sense that your life will be hella changed if you have an accident and end up with chronic pain).

Every car has powerful enough brakes, braking upgrades are mostly just for racing needs; but stock tires are still very often just total garbage and the first thing you should replace.