JC Lacayo

I would not go wider than 315.

There's also Toyo, Nitto, Yokohama, continental in 315-25-19 size. I can't vouch for them but they are usually available, unlike the PS2s.

Dock

Here is your quote I replied to:

"Dock, appreciate that advise. I use to run PS2's and loved them....until I found PSS'....they blow the PS2's away. They last longer, they are quieter, and they have far better grip in the dry and wet. I won't go back."

As I said, I think the Michelin PS2s provide way more grip than a driver can reasonably use on the street.

Dock

Duc Hunter, where do you live?

Duc Hunter

Florida....so wet traction is important as we get downpours like they saw in Malaysia last weekend for the GP.

Duc Hunter

Sounds great...but the 25 scares me for a mostly street drive car, between pot hole and the rougher ride. I know, PICKY!

Dock

I guess I'm wondering why you don't think PS2s have enough wet/dry traction for street use. If you're not going to track the car, it doesn't seem like there are enough curves in Florida (excluding cloverleaves) where you can really go 10/10s for very long at all (assuming you are willing to take the car to 10/10s cornering on public roads in the first place). In what will probably be a larger percentage of driving on straight roads, it's hard to see where the difference between the PS2s and PSS' would be a deal breaker.

Carlo_Carrera

If you want to get rid of the understeer invest in adjustable sway bars (cheap) or consider changing spring rates (expensive). Then you can stick with OEM tire sizes or step up to 245/40-18 front and 315/30-18 rear. Which is what I run on stock wheels.

Duc Hunter

Doc....per Michelin's testing the PPS has 6 or 7 major areas where it is much better. The three that are important to me are

• Road-holding on wet surfaces: Time was reduced by 2.5 seconds on a 4,100-meter closed-circuit track.
• Total mileage on the track: 50% more laps.
• Total mileage on the road: 10% greater distance.

Again PS2's are great, real experience though tells me they last a lot longer, is more quiet, and better in the wet.

Dock

And how does this relate to predominately straight public roads in Florida?

I just don't see where any of that is an advantage, especially the noise and wet performance:

The "lasts a lot longer" advantage, assuming the data is credible at a 10% improvement (PSS over PS2), is only ~700 miles on a 7000 mile rear replacement interval for the PS2s.

The noise differences can't be much at all (if any) since the PS2s are very quiet.

And one would think that prudence in the way one drives the car would negate any wet performance advantage (likely small, if any at all). I know I certainly wouldn't be upping the speed or cornering, or compressing braking distances on wet roads just because I have PSS tires instead of PS2s. I'd be way below the performance maximums of either tire on wet roads, using neither of these tire's full abilities, so any any performance advantage would go completely unnoticed.

DaveCarrera4

I run 19" Toyo T1R 315/25's in the rear. Wheel placement perpendicular to the car becomes critical. Fenders are not rolled, and there is about 3/4" gap between tire and fender. Had to space out my 997 turbo wheels so the tires didn't rub the wheel liner bulge where the inter cooler hose runs. It all works, but did take some trial and error to get the right size spacer. Sorry I cannot remember the spacer width. Tires have been pretty good for street and a few track days per year. The 25 ratio does mean a harsher ride though.

Berra

Does the Awd in the Turbo handle GT2 Wheels without any issues? Some say it does, some say it will harm the system.

mcbit

For me it made the handling very squirrelly when on the power and noticeably slowed top end acceleration. Shouldn't damage the system though.

Went back to stock and much prefer it apart fro the looks which I really like with the GT2 setup.

C'est la vie.

jumper5836

It is fine, the sizes are within the rolling diameter tolerances of the system.

DaveCarrera4

If you read original post, duc describes overall tire diameter requirement. Same or slightly larger up front is preferred by viscous coupling. Of course the speedo will be off if moving up or down from stock tire diameter.

Duc Hunter

I have seen out here "some say" (TopGear ref since it is ending) you can run 255 or even 265 up front. No one here has mentioned more then 245/40-18.

Went back and looked again....wow is the 18" selection small!

I have seen several tuners running 235/40-19.....305/30-19?

Anyone think 245/40-19.....325/30-19 would fit?
What about 245/35-19.....295/30-19?