I did a bit of digging, and asked OZ about a set of 20" Ultraleggeras for winter use. They currently only offer a 12" rear, and told me I would therefore have to fit 305 rears as these guys did not sanction 295 width on a 12" wheel: http://www.etrto.org/page.asp?id=1794&langue=EN

Turns out for wheel/tyre combinations to be legal here in Swizerland, they have to be sanctioned by ETRTO as well. Not sure about Germany, but Porsche went to the trouble of specifying a new width of rear wheel just for the Turbo S winter package. I doubt they would have bothered if 295s on 12" wheels was within spec.

I know some have fitted them to the OE wheels without issue, but I think i'll end up with an 11" rear wheel of some kind.

 

I considered the issue of installing the 295 tire on a 12" rim. Michelin's specs say min of 10" and max 11" for the 295 however when I looked at the Sport Cup 2 tire even the spec for the 305 says 10.5" to 11.5". So even the 305 is too narrow for a 12" rim according to Michelin. Perhaps if I was running high lateral g's there would be less protection against the tire rolling over but I don't drive like that in the winter so I was ok with it.

I've attached a picture of the rear wheel with the 295 tire and the tire extends past the wheel to protect the rim somewhat. I'll likely try to pick up a different set of wheels for next winter because I don't like taking tires off wheels and having to re-balance twice a year.

 

During the winter, a good tire will feel close to an R-comp tire, better than an all-season tire, and much better than a summer tire. That's a good incentive to get winter tires, beyond the benefit of being able to drive in some snow and ice.

 

Just drove this morning in Seattle in 19 degree weather to our Porsche breakfast club we have every Sunday at 0700. Just put on my sottozeros pirelli winter tires on my 07 gt3. 295 on 19x 11 oz ultraleggerras rears. 235 30 19 fronts. 4th season so far. 2 with C4S, on my 2nd with GT3. Had to change rear OZ due to offset differences. No worries with this winter tires but still always on the gas to keep the back end planted and nothing crazy.
2015 gt3 with sport cup 2 arriving this week Won't drive it if below 35 degrees.

 

I see Suncoast is offering an "OEM" winter Wheel & tire package for the 991 GT3. My local dealer has also offered me a "factory" wheel/tire combo - they said the wheel used is a "turbo" design, and that they can't specify which of two tires, Michelin or Pirelli winter rubber, the set might come with. Either of the above options entail a 2nd set of 20" rims, Front 9 x20" with 245/35's and the rear 11 x20" & 295/30 rubber.

My question, is anyone running 19" rims and tires? Is there a fitment issue with 19" rims and the (what are the, 410mm diameter) PCCBs? If I am going to start up a new wheel/rims collection for winter/track tires, I think I'd like to try using 19" rims unless there are fitment problems. Any personal knowledge or look out gottchas on using 19's appreciated.

Thanks, mlp
Colorado

BTW, does anyone know the "name" for the wheel in http://www.suncoastparts.com/product...3CHASSISWHEELS
Is this the "Turbo" look?

EDIT for 997.2 GT3 fitment 19' options: http://www.suncoastparts.com/product..._Chassiswinter

 

Unfortunately, you can't run 19" rims with PCCBs. I ended up going with the Turbo set in 9x20" and 11x20" after looking at all the options.

At about $5k for the wheels, when you factor in the cost of TMPS and Rubber, they're not priced too badly.

 

I have the Alpin's 295 30 20 and 245 35 20 fitted on standard wheels 250 miles running in so far. No problems or rubbing even on full lock. Nothing to compare with, as I had these fitted before I drove on the cups it was delivered on, good feel and grip in cool damp conditions. Not had any ice or snow yet.

 

mlpor, I believe you can specify which tires you want. Porsche lists the 991 044 600 70 part number for the Michelin winter set and 991 044 600 80 as the Pirelli set.

 

Perhaps one can, I'm just relaying the information my SA on the transaction gave me, "We can get a factory package, but parts/service is telling me they (the service department) can't guarantee which of the two tire choices the wheels will show up wearing." Don't know if this is a peculiarity of my local dealer, or not. FWIW, even offering (they say) a special friends pricing, the package is still @ $900+ more than Suncoast's deal, local taxes vs. shipping are probably pretty close to a wash.

Picked the car up yesterday afternoon. Quite a different feel to it vs. the 981 Cayman I turned in. Thanks for the PN#'s. On the brighter front, looks like the car already has a FULL (& I do mean full) clear bra installed by the original dealer/owner. It wasn't obvious at first since the bra covers the entire hood, clear to the windshield, so there is no "bra line" one usually sees @ 1/2 up the front bonnet. The only thing not covered is the leading edge of the roof line.

 

There was no difficulty getting the Alpins with the TTS wheels by my dealer, and they met the Suncoast price. See details above.

Good luck. Enjoy the ride.

 

delete - not relevant to thread topic

 

After lurking and researching, wanted to share my conclusion. On stock wheels:

245/35ZR-20 Pirelli Winter Sottozero Serie II in the front
305/30R-20 Pirelli Winter Sottozero 3 XL in the rear

Way cost effective, and fitting the exact manufacturers specs/sizes. So let the debate ensue over running different models on front and rear. My theory is that the staggered setup in and of itself creates a difference in traction front to back, so a tread pattern will just be another difference from front to back. They've been awesome so far!

 

I think it's a better option than stretching the Alpins. I ended up going with the new rims so I could beat them up in potholes - sadly most of the big potholes are on the freeway sections here, so if you're going to hit one it's probably at speed.

I like the GT3 rims too much to destroy them in the first few months...

 

Just put on Alpin 295 30 20 and 245 35 20 on Forgeline (Graphite Finish) wheels.
It's my experience you can't run 19's even with steel brakes either.
There are clearance issues with the rear trailing arm.
The inner diameter of the wheel is about 19 1/2" on stocks wheels and
it barely clears that arm. In one pic you can see what happens when 19's
are put on. Some people will flip that bolt around on the trailing arm
to get clearance and file down the other end. But I didn't want to try that.
Best to use 20's.

 

Decided to embrace winter here in Minnesota and put winters on my GT3. went with 245/35r20 and 295/30r20 Michelin Alpin PA4 on 20x9 and 20x11 OZ Ultraleggera wheels. 11" rears meant not stretching the 295 so far and bit more rim protection maybe? They look great but with the rear offset on the OZ rears they are slightly pushed into the wheel well compared to stock. Don't love the red ring on the wheels but I was over it once I got back behind the wheel after a couple months of no GT3.

Good tools make the center locks no problem just time consuming. And that damn grease getting everywhere (latex gloves came in handy). Irwin clamp and a lift made this a single person job.