OEM primacy HP vs OEM PS4S stiffness
 

I've long been a supporter of the stock primacies because of their stiffness and feedback. I believed part of this was due to the Eco rating which requires a stiffer sidewall resulting in less rolling resistance. Now that the 4s have the Eco rating I'm willing to give sticky tires another shot. I believe the 19 TRD edition and brz ts have these tires. Any input from owners of the new PS4S?

Thanks.

The primacies sidewalls feel no stiffer than a decent set of performance tires like the mpss. havent tried the newer ps4s.

The PS4S are a very good street tire. You'll like them. Get a good alignment while you're at it.

- Andrew

Except they are available only in US :( in usable sizes. only 19-20-21" in EU, just non 'S' PS4 being offered in usable sizing for twins. And non 'S', while great street tire, runs a bit short for dual-use daily and track tire.

Went from the stock to MPS4S in 225/45 R17. Would never think on going back. Unless you have changed wheels I would stay with the stock size.

Does PSS/PS4S ruin the raw and sporty feeling from the stock tires by being too mushy/floaty due to softer compound/sidewalls?

I believe main decision for factory to fit primacy HP was the sidewall stiffness. I don't think it is a coincidence when they installed higher grip tires (MPSS, PS4) they went in 18" wheels.

When you say they installed the PS4 on 18" wheels, do you mean they did so to get a thinner sidewall to try and offset the soft sidewalls? And doesn't the PS4's on the BRZ Ts come on 17" wheels?

Yes. A thinner sidewall could offset a softer sidewall. All tS editions in US and Japan had 18" wheels. They didn't do it for Brembo clearance, because the PP editions had a 17" wheel with Primacy HP.

Serious?
"raw and sporty feeling" from tyres that were stock on a Prius...
"too mushy/floaty due to softer compound/sidewalls" for tyres they fit on Porsche GT3's...

I think it's a false premise that stiff sidewalls equal feedback or "feel".
Tyres are hugely complex structures with side wall "stiffness" being only one part of a technical jigsaw, that is often counter intuitive.
Remember, "run flat" tyres have stiff sidewalls and they are way way less than ideal...

I have never heard a tire to be categorised based on which car is fitted like for example in some Prius models. This nonsense is mentioned only here. Good tires might be fitted in econ subcompact cars and in more expensive cars. There is a reason tires come in different sizes. What should we say if these tires came in a BMW 3 series? That it's wearing Prius tires? Lol. Designers were looking back in '12 for a tire with stiff sidewalls. Everything else is a coincidence.

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I have never read or heard that "stiff sidewalls" (whatever that actually means) was the criteria for the initial tyre choice on the 86/BRZ.

At the time of the 86/BRZ release the much stated primary intention of the tyre choice was about the car not having too much mechanical grip... and yes, at the time, much was made of the fact that it was the same tyre as fitted to the Prius. Toyota itself made a point of it, as did every single road test journalist. It was not just a "coincidence".

Yes, the stiffness is one of the aspects that I personally find makes the car feel more like a sportscar and induces excitement. From your point of view, sporty tires should be categorized based on what type of cars they are fitted on?

Also, I'm not saying that soft sticky tires aren't sporty, but I'm simply trying to figure out if it gives up on the stiff feeling property of the stock tire.