JAM2

I used the 315/30/21 Mercedes ps4s tire on my gt3. No issues whatsoever.

DallasVP17

That’s great to hear! I guess I was over thinking it. Lol

diononiz

I don’t think there will problems. I am just wondering if the Porsche labeled sidewall tires will be better since they were designed to work with our cars.

PPS

The original Goodyear Assymetric 3 305 on the right and the Mercedes marked 315 on the left. As we know, one 305 isn’t the same as another and I found that the Assymetric is way bigger than its name or the other way around. No matter what, these tires are exactly the same size and my 4S didn’t recognize any size difference what so ever.

Michigan 992

PPS - you are correct. The actual P Zero tread width is much wider than the original Goodyears. The Michelin 315/30 - 21 is very close in diameter to the OEM tires and only slightly wider across the tread. The labeling difference of which OEM's approved the 245's versus the 315's does not mean they are different compounds. It simply means that the same OEM wasn't using both tire sizes when they were testing/approving tires.

IF these were race tires I would be more concerned based on what I have seen during tire development for vehicle projects I have worked on. Some suppliers made many tries at getting the compounding right. Others just showed up with very good tires from the start and helped with dialing in tire pressures, suspension set up tweaks, and damping rates. This last part sounds minor, but you would be amazed at how much it can transform a performance car that seemed to be already be very good for most drivers.

My opinion is that the Michelin PS-4's that are currently available would be very good on the 992 with their pressures appropriately dialed in. That is just my opinion with no 992 data behind it.

PPS

I think so too. However, I wasn’t being clear - the reference to 4S was 992 4S and the Michelin’s are Cup 2’s 😀

AKSteve

I just put a set of PS4S tires on my car today mounted on OZ Legerra HLT wheels. I went with N-rated front tires in the stock size and the Mercedes-rated 315's in the rear. These tires are so super sticky. I really love them. And from my experience, they also work better in colder temperatures than other ultra high performance summer tires. I need to adjust the tire pressure tonight because all 4 tires came with the pressure set at 36psi. I'm going to go with 33/38.

rk-d

I still think it's insane Michelin doesn't have 992 fitment. This car is like the Honda Accord of European sports cars.

315 width is the max tire size that I think will fit 11.5 inch wheels.

The sidewall will be a little taller - Michelins seem to run a little chubbier in general compared to Pirellis. I actually prefer the look of a chubbier sidewall than a stretched one.

Personally I'd go wider than narrowing the sidewall. Beyond the ride comfort issue and the smaller margin of error for banging the wheels -- aesthetically, a shorter sidewall will accentuate the wheel gap.

AKSteve

And no wheels on TireRack except for the OZ HLT Leggera that I just bought. They have them in black and silver, but no wheels from other manufacturers. I'm happy with the OZ wheels, but I generally purchase BBS wheels and they have nothing available yet. And it's not like the 992 just came out. It's been out for quite a while and still nothing.

rk-d

IKR. No BBS FI-R even though this is probably one of the most popular wheel upgrades on this car. Such a huge market that's being ignored.

AKSteve

But Porsche has many fine and expensive wheel/tire packages that they will sell you. They've also made sure that the recommended winter tires size "doesn't fit" on the stock 11.5in wide rear wheels and recommend that you buy a new set of $6K winter wheels/tires from them. I decided instead to have a set of the 295 width Michelin Alpin5 winter tires mounted on my stock rear wheels and they fit just fine.

inastrangeland

The 2021 Turbo S comes stock with 315/30/21 rear tires on 11.5" wheels. And, it does not need Porsche seal of approval. The key is the speed rating. The German car manufacturers make a bundle selling their special tires and the public believes they are special. They are the same tire. Fitment on the wheel and speed rating. I would also add load rating for a heavy car but most high speed tires also have the XL load rating. When replacing the tires on my new car, I will definitely be getting the PS4s in 315/30/21 for the rear, just like the Turbo S.

AKSteve

^ Which tires specifically come with the 2021 Turbo S? They aren't Michelins, right?

inastrangeland

Michelins. Pirelli. Continental. Take your pick.....

https://www.tirerack.com/tires/TireS...earDiameter=17

inastrangeland

From the tirerack web site for Michelin tires...

O.E. Max Performance Summer tires are typically purchased as direct replacements for worn-out pairs/sets of thevehicle's original tires. They can also be used for other vehicle applications in complete sets of four or axle pairs if available in an appropriate size, loadrange and speed rating to match the existing O.E. tires' performance category and specifications.