OEM primacy HP vs OEM PS4S stiffness

[nikitopo]

Originally Posted by grumpysnapper

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".

Check below snapshots. They are saying that they are ECO tires, but also expensive and well balanced tires. They wanted to focus on the suspension and body development and they decided to use these tires. They mentioned that these were also fitted to Prius (performance package in Japan) to point out that you can develop a good handling car without focusing just on tires and speed. There are also other aspects of handling like agility and good balance of the whole car.

And as said before these particular tires were provided as a factory option in BMW 3-series and 5-series. No journalist ever said that BMW was doing this to provide less grip on their cars. My personal point of view is that the mentioning of the "Prius" tires by the designers was an unfortunate moment, because they didn't manage to pass clearly the message. Then journalists either misinterpreted the argument or just distorted it for their own interests by saying it has "crappy" Prius tires.

[Capt Spaulding]

Originally Posted by grumpysnapper

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".

Originally Posted by ItsReiko

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.

When you say a "stiff feeling" what exactly are you talking about? Response over bumps? Harsher = stiffer? Feedback through the chassis (steering wheel, pedals, seat)? Hard compound? Lower grip level?

Can you elaborate on what a "sporty" feel means to you?

[ItsReiko]

Originally Posted by Capt Spaulding

When you say a "stiff feeling" what exactly are you talking about? Response over bumps? Harsher = stiffer? Feedback through the chassis (steering wheel, pedals, seat)? Hard compound? Lower grip level?

Can you elaborate on what a "sporty" feel means to you?

Yes, I want a tire that retains the stiff feeling where when you go over a bump or rock, you would feel it through the car. Not crashy, but a dampened yet obvious feel of the road imperfections.

What I'm trying to stay away from is a tire that would instead cushion those bumps like more luxurious cars and in the process make your car feel disconnected from the tarmac and become floaty.

So back to my original question, would the Ps4s fit my criteria?

[nikitopo]

I don't think PS4 S will make the car floaty. You might lose a bit of steering feel if you keep the stock wheels, but it should not change radically the car. On the other hand, the PS4 has been said to have softer sidewalls and to lose information. A stickier tire that gives faster laps, it doesn't mean that it is always better. So, take care that you fit the correct tire.

Here is the correct tire: https://m.tirerack.com/tires/tires.j...odClar=Limited

[churchx]

Due being in EU and having only "normal" PS4 available in 17", not PS4S, i tried only it. And with stock sized those (on x7.5" though) steering felt sharp enough despite being more street oriented. Non-S didn't stand well to track overheating though.

[nikitopo]

Yes on 7.5" wheels on a stock size tire the PS4 will behave better.

[grumpysnapper]

The PS4S is an exceptional tyre that's designed with fewer compromises than a Primacy (ie. it doesn't have to cover such a broad spectrum of potential uses that a Primacy is intended to).
You will not be disappointed with a PS4S, and it will not feel in any way "less sharp", it is a number of steps up the ladder in that regard. In fact it will probably highlight other improvements that could to be made over the standard suspension.
I have never said the Primacy was a rubbish tyre because it was standard on the early Prius (and journalists at the time did not say that either!), but rather that the suspension engineers specified it because of some of its inherent characteristics... one of which was not endowing the car with too much grip (ie over tyre-ing the car).
I truly don't understand the fixation on "side wall stiffness" in this particular context as I'm not sure that it is necessarily the magic ingredient that you may believe it is in a tyres "sporty" feel.
Whether or not you want/need the extra mechanical grip is probably a more interesting question.

[Capt Spaulding]

Grumpy has covered most of the bases. I'll add that my experience has been with Continental EC Sports. That has been that the Primacies were low grip tires - the limits of the tires were quite low. On very good asphalt a modestly brisk pace would generate screaming worthy of a 3 year old's temper tantrum.

The ECs are much less dramatic - the limits are much higher. I did not notice anything that seemed to deaden the feel through the controls or make the car seem to "float." Some folks like the "friskier" nature of the OEM tires. If you like the lower limits stick with them. I got tired of countersteering in situations where I didn't think I should be having to do that or having to listen to the tires caterwauling and extracting my wife's fingers from the door handle when we stop for a light. I find the car much more enjoyable - YMMV.

[nikitopo]

You don't need to change the tires to fix countersteering behaviour. They "fixed" it in +'17 models without changing the tires.

[CSG Mike]

Originally Posted by Capt Spaulding

Grumpy has covered most of the bases. I'll add that my experience has been with Continental EC Sports. That has been that the Primacies were low grip tires - the limits of the tires were quite low. On very good asphalt a modestly brisk pace would generate screaming worthy of a 3 year old's temper tantrum.

The ECs are much less dramatic - the limits are much higher. I did not notice anything that seemed to deaden the feel through the controls or make the car seem to "float." Some folks like the "friskier" nature of the OEM tires. If you like the lower limits stick with them. I got tired of countersteering in situations where I didn't think I should be having to do that or having to listen to the tires caterwauling and extracting my wife's fingers from the door handle when we stop for a light. I find the car much more enjoyable - YMMV.

My question for you would be, why are you needing to countersteer? Did the rear step out on its own, or did you get a little exuberant with throttle application?

[Ultramaroon]

Stock tires are fun. They are the Goldilocks tires for the platform. I don't want/need more grip. I like a bit of predictable slip angle at legal speeds. Sidewall stiffness pairs nicely with the grip level.

And yes, the stock setup pushes. It's designed for the general public. Of course it pushes. If you're kicking out the tail unintentionally, you're doing it wrong.

[glhs386]

Originally Posted by Capt Spaulding

That has been that the Primacies were low grip tires - the limits of the tires were quite low. On very good asphalt a modestly brisk pace would generate screaming worthy of a 3 year old's temper tantrum.

Exactly this. I'd never driven a car with tires that squeal while doing a normal u-turn until I drove my FR-S on the OEM Primacies. I never found anything remotely fun about them and couldn't wait to get them off, literally nothing redeeming about them besides perhaps fuel economy. The PS4S is a genuine upgrade in performance, seems about equal in road noise and comfort, and is less expensive to boot. If someone does want a low grip tire to drift around on, you can buy some decent all-seasons for half the price. Replacing the stock tires with another set of Primacies is essentially like setting money on fire.

[churchx]

"normal u-turn" bit is arguable. When few years ago i drove first times in mine, i noticed that i often take turns/roundabouts at higher speed/pace then in my previous cars. I guess, (possibly many do) because gauged safe speed from car's roll extent (obviously higher in more comfort oriented/softer sprung/of higher center of gravity family cars/SUVs) aswell, and as this rolled less, i pushed more. And if so, i see nothing out of order, if tire slips extra from time to time. It even provided me extra fun moment. It's upto driver to gauge grip level and drive accordingly. I wouldn't claim that even on primacies twins have less grip and are less capable then other cars. I just pushed more. On track, even on supposedly "gripless" primacies, i could drive faster then on many "family cars", that supposedly "don't squeal" on "normal u-turns".

[RToyo86]

I have stock sized PS4S on a set of 8" wheels. The difference in stretch vs 7" wheels may effect the responsiveness of the tire.

I view the PS4S as a straight upgrade. Grip, response, road noise, wet performance.
The main downside to me is that the factory spring rates clearly weren't designed for that amount of grip. Last summer on stock springs I could easily put the car on the bump stops in corners.
The car still handled great, but it obviously felt different. Pros/cons.

I wasn't a fan of how it felt. Since adding RCE yellows and camber bolts the suspension feels way happier dealing with the extra grip.


Primacys are a ton of fun on the street. So grip limit is so approachable, you get chirps and squeals before you get near the limit. Really just depends on how you like to drive...