Tires sizes recomendation

Don’t. FWIW, a lot of tire places won’t install anything other than spec’d. It’ll throw off the odometer (obviously), change suspension geometry, increase wind resistance. All just incrementally, but really no upside.

Can you rephrase that? Hang on, think I understand, getting fluent in typo.

 

A wider tire generally has more of a tendency to hydroplane than a narrow one not less.

That freeway feel might be due to wrong tire pressures or alignment being off or something loose
in the steering or suspension.

Don't fight with the tire suppliers on this one.
It isn't worth the hassle.

 

Optional tire sizes on our Prius Primes from Tirerack

 

^ These all stick pretty close to stock OD?

 

You bought a prius because you wanted to maximize your mileage and reduce your emissions footprint. Any size other than stock is going to move you away from that. Stick with the size you have from the factory.

Costco shouldn't have an issue with tires other than stock as long as it fits the wheel. My tacoma had stock 265/70/16s. I had costco install 255/85/16s. They had no issues at all.

 

If I was buying 15" all-seasons the Defender would be a top contender. My son just got some for a Mazda CX-5, happy with them. There's a new iteration I think, just came out this year. One downside, it's been mentioned here a few times you'll take a mpg at the outset, but I think it rebounds some.

 

I've been happy with my CostCo Michelin X-Tours (aka Defenders). Pic from Consumer Reports.

 

Curious, have you got similar for snow tires?

 

"not that stable on the freeway"
This isn't about tire size. This is something unique to your car. It could be tire pressure or something bent or something else that needs fixing. Get it checked. For tires in L.A., those Michelin Defenders are a very good choice. (My next Prime tires will be the new Bridgestone Driveguard Plus run-flat tires, but they aren't yet out in the Prime size. More comfort and better performance from the newest run-flat tires said to be good for 50 miles at 50 mph without air--then they're junk.)

 

Now, we need such a rating chart for all-weather tires, the all-season tires with the winter snow service symbol on the side, the 3 peak mountain snowflake symbol for passing the on-snow traction test.

 

Tyrereviews on Youtube does a lot of A vs B testing for tires.
Any new tire will do better than worn ones for hydroplane resistance. With that said, SOME tires excel more than others, even when comparing new vs new.

Continental DWS06+ excel in every aspect for wet performance, but it will for sure take a MPG hit compared to LRR tires as speced from the factory.

**Purely hypothetical (since continental does not make the dws06+ in 185 width**: If factory is 195-width, you can probably go with 185 width summer-focused tires and still get comparable MPG vs stock, but gain the extra confidence in non-LRR tires and uprated wet performance.

 

Any new tire will give lower mpg or miles per charge. The deeper rubber tread has more squirm which is energy wasted as heat. That's just the way it works. Low rolling resistance tires, for which there is no industry standard spec, has some benefit and some drawbacks. One way they get lower rolling resistance is with rubber compounds with more bounce-back. As the tire rolls the part on the bottom gets squished, then returns to shape as the rolling continues. If the return to shape is somewhat bouncy you get part of that energy back. If the return to shape is slower and the energy to compress the rubber mainly turns to heat...you lost that energy. Think of dropping a new tennis ball and an old tired tennis ball from the same height. The new one will bounce back higher--less hysteresis; less loss. The drawback might be that the LRR tires won't have the optimal tread compound for longest tread life or best traction. There's no perfect tire.

 

PDF compilation of @Marine Ray's two CR tire rating pages attached: