Background - not a daily driver, stock everything non-CR. Had an '02 for 10 years, took a 6 year break and am back with an '08. Planning to get off the all-seasons the car came with. Tracked my ap1 a fair bit, I probably won't track my ap2 right away (in other words, I probably won't track on whichever tires I end up getting this time around).

Was initially thinking - easy choice, just go with Michelin PS4S; then started thinking that more is always better, so why not run 225/255 tires. But PS4S not available in 255/40R17 ... so now what? Bridgestone S-04s? Firestone Indy 500s?

Been a fan of Michelin for a while, so I figured I'd just drink the PS4S koolaid and keep it simple. That said, I never ran Michelins on my previous S, so not sure if their "goodness" translates from my other vehicles to this car. Of course, RE71-R is tempting too, but not sure I want to worry about getting caught in the rain (it never rains just a little when it rains here), and I'm reading reports varying from "what noise?" to "too damn noisy to bear".

So I guess there are a couple of questions in here: Would I gain anything noticeable with an upsize? If so, what's the current hotness? If no huge gains from that, what're people's opinions on the PS4S? Thanks.

 

 

AD08R

 

All reports are the P4S is far and away the best high-performance street tire available. The difference between 225/255 and 215/245 is minimal on the track or on the street. It is probably more noticeable in ground clearance. On mine, it was the difference between scraping on the driveway or not.

So, P4S.

For track or autocross, that is not the first choice. Then it depends on the class and the rules. For autocross, at this time, the S2k doesn't appear to be the choice for the pointy end in either Street or STR classes irrespective of the tire choice. The preferred tire is the RE71r or BFG Rival S 1.5. For track work, it depends on your budget. There are cars running 315/30-18, 335/30-18 Hoosier A7s (they are the same diameter in the Hoosier A7/R7). 295/30-18 is also possible and available in many trackable tires. In addition to the Hoosiers, Yokohama has the A052, Toyo has the R888R and RR, and there is a Federal in the 285/30 size (same OD as the 245/40-17). The Maxxis RC-1 also comes in a slightly narrower size. All of the large tires would need wide wheels and fender modifications. There is an aftermarket suspension kit that replaces all links and uprights, lowering the car 40mm while maintaining geometry.

But to keep the car stock, 215/245 P4S.

 

I was pretty much ruling that out due to the diameter differences between 225/45R17 and 245/40R17 ... 225/255 are a perfect match, 215/245 come pretty damn close; 225/245 are .3" off. Not particularly sure how big a deal that is, but that's my thinking.

WRT to over/under steer - I get what you're saying; but I'll admit to having a hard time feeling either on public roads. I did find my ap1 (stock suspension/wheels, R compounds) to plow on track in certain corners (then again, it did come around on me a couple of times too).

 

Yeah, I'm leaning that way. Only possible negatives I've seen on teh webs is some vague gripes about Michelin's sidewall stiffness ... never noticed that on my 370 running PSS, but I never really pushed that car.

 

It is not a track tire, but it is far and away the best street tire.

https://www.tirerack.com/tires/tests...y.jsp?ttid=223

 

Tire sizes under consideration: Under/oversteer on the street pretty much not affected at all. On track, barely if at all. On OEM AP2 wheel widths I'd be looking at 215 fronts, with either 245 or 255 rears. Or *maybe* 225 fronts but only with 255 rears.
I would avoid 225F/245R based purely on aesthetics as pooched and taller front tires looks goofy with OEM-fitment shorter and less-pooched 245 rears.

After being somewhat disappointed with PSS as street tires on my FD, I reverted to Extreme Perf tires only on my cars. For warmer months anyway!

RE71R are absolutely *AMAZING* in the rain. At least with some tread depth. On the track at Palmer and at Watkins Glen in the pouring rain this year I astounded a couple of very experienced and fast drivers in faster cars on Hoosier H2Os by catching them in my BRZ on new RE71Rs. Got enough attention that RE71R got a point bump for 2019 with my time trial club, COMSCC.

 

On this car sidewall stiffness makes a huge difference, whereas on most any other car it barely makes any difference (except with ride comfort).

Wider front tires make turn in more sluggish.

Any modern max performance summer will far exceed the grip of the oem tires this cars suspension was designed around.

There is an argument to be made, that for the street, stock sizes with a max perf tire known for stiff sidewalls is an excellent choice. You may give up some possible grip over other choices, but those come with the downsides mentioned above.

How important those downsides are will vary with person and purpose. So ideal decision for one isn't same as another.

The only bad decision is an uninformed or unconsidered one.

 

Tire technology is a moving target.

I ran Dunlap Star Spec (somethings), then Bridgestone RE-11A tires for a couple of years and when found they were no longer made when I needed new tires I tried the S-04 tires in "CR size" on my '06. 215f/255r. Great street tire setup. May go 225/255 next time. Other choice was the always darling RE-71R but they're very noisy.

-- Chuck