After my 2-day DE with PCA-GGR at Thunder Hill, I feel that the stock tires probably won't last too long with a couple of more DE events. I measured the tire depth with a gauge, and both front and rear shows 6/32 inch, with 5.5K miles. So I decided to get a set of 19" wheels since tires will be cheaper for the smaller size, and should be lighter too.

Checking prices on Tirerack, I see the prices for OE Pirelli P Zero as
Front 245/35/20: $365 each
Rear 295/30/20: $525 each

Since I want to keep the same overall tire height, I went with 245/40/19 Michelin Pilot Super Sport for the front, 295/35/19 PSS for the rear. They are $287 front, $452 rear.

Now, for wheels I narrowed my search to OZ Superforgiata and HRE P43S, and decided to go with OZ since they are cheaper on Tirerack and are amazingly light. According to Tirerack's web site, front is only 16.5lbs, and rear 19lbs. So I pulled the trigger and have Tirerack mounted and balanced the wheels with TMPS installed too. Jonas at Tirerack is very professional and helpful, and two days later the whole set arrived. That's really fast!

I spent this Sunday morning swapping the wheels, and also use my bathroom weight scale to check the actual weight of OZ wheels vs OEM Sports Design wheels. Here's the result:

OEM Sports Design front: 48.2 lbs
OEM Sports Design rear: 62.5 lbs

OZ Superforgiata front: 41.8 lbs
OZ Superforgiata rear: 50.2 lbs

Needless to say, I am pleasantly surprised. 6.4 lbs lighter in each corner of left & right front, and a whopping 12.3 lbs lighter in each corner of left & right rear!

After tightening the wheels to Porsche's torque specification of 118 ft-lbs, I was eager to try it out. I decided to go for a back road drive up the mountain to the Lick Observatory in the south bay area. The drive up to the mountain is very twisty and narrow, and average speed is about 35MPH, so I won't be going too fast. It should also give me an idea how the new wheels and tires handle.

On the freeway I did not feel much difference. But once I was on the mountain road and started to take these corners, I immediately felt a difference. The car seems more nimble, and turn-in is sharper. Compliance is excellent, never harsh, and grip is phenomenal. The onboard G meter said I hit 1.0G turning left, don't know how accurate it is, but that's amazing. Usually new tires are greasy, but I didn't feel it at all. PASM & PDCC kept the car flat, and I had a blast. I have to restraint myself from pushing faster since this is not a track, but my confidence on these tires is very high.

Compared to my last 997.2 with 19" HRE P43/Michelen PS2, the new 991 does not push as much, and i have higher confidence pushing it to the 7/10 limit. The 6 piston front brakes are amazing too. Overall I am very satisfied with the OZs and Michelens. Next weekend I am going to Thunder Hill again for the Hooked on Driving event, and will see how these hold up on the track.

I took some pictures, see below:

1. Front & rear (left to right)
2. Front tires comparison. Left is Michelen PSS, right is P Zero. P Zero seems to have picked up "marbles" from the track, although wear seems to be uniform.
3. Rear tires comparison. Left is P Zero, right is PSS. Again, "marbles" and wear seems uniform. Maybe PDCC is helping the tire stay flat during cornering?
4 & 5: How the OZ wheels look on the car. The color is sort of muted gunmetal, compared to stock's bright silver, and seems to make the whole a bit understated.

Now I wonder if there are lighter aftermarket brake rotors...

 

From an aesthetic point of view, I like the your 20" OEM wheels better. The 19" wheels look small.

 

Good economic thoughts. Can't wait to hear how the g meter compares.

ChuckJ

 

Awesome Conrats! They look great to me. Im prob gonna pick up a set of Ultraleggeras. Its good to know that the OZ 19's clear PDCC cars. I just wish there were some more tire options for a track setup

 

I agree, although the muted gray color might make it look small too. Since it's for the track, lighter weight has higher priority.

 

I just finished a 3 day track event at Pocono. My rears have worn better than expected (I think they have at least a few more track days in them) but the front left started to shred on Day 1 and now needs to be replaced. I blame this more on this track, which I'm told is known to be v abrasive, than the tires. In fact, 3 drivers corded their tires in the first session on the first day (it's a newly paved NASCAR track).

Anyway, re PDCC and tire wear, absolutely IMO I think it makes the tires wear more evenly. Even on my ruined front tire, it was away from the edge (in the outboard) and no cording -- I still ran days 2 and 3 on it with no issues.

I'm confused though why you bought MPSS as a dedicated track tire? It's a wonderful combo street/track tire but similarly (or maybe even more) soft as the OEM Pirelli's. None of the track tires (888's, Sport Cups, Hoosiers etc) is available in that height??

 

glad to see you put these to good use! were your running OEM lugs?

 

Well, since I am still a beginner, I think I was driving only 7/10 in my first DE event. I figure that the noise from the street tires would help me know the grip limit. Plus, I don't want to tow the track tires from home, I want to drive there and back home on the track tires. After I have learned to explore the full limit of my car, then I would start considering these track-oriented tires.

 

Yes, the OEM lugs work. Since I also have the OEM 5mm spacers, the OEM lugs are necessary.

 

Sadly there arent very many options available for 19's. I agree that the PSS's arent the right tire for a track application. I had them on my M3 street car and they turned to butter after a while and are pretty pricey IMO.

I have heard that varying the outside diameter/height of the tire more than 5% from oem causes the TC to behave very strangely. I have not confirmed this yet. SM ATL runs 235/35/19 and 295/30/19 R888 setup, which is 4% smaller F & R than stock if my calcs are correct, without any issue. The shorter tire actually provides shorter/lower gearing which would be good for track use.

Tires I am considering and their stated OD (oem = F 26.8" and R 27"):

Hankook RS3
245/40/19 F 26.7"
275/35/19 R 26.7"
305/30/19 R 26.3"

P Zero
245/40/19 F 26.7"
255/35/19 F 25.4"
305/30/19 R 26.2"

Toyo R888
235/35/19 F 25.7"
265/30/19 F 25.4"
295/30/19 R 26"
305/30/19 R 26.5"

Bridgestone RE-11
245/40/19 F 26.7"
255/35/19 F 26"
305/30/19 R 26.3"

Any thoughts or suggestions on tires is much appreciated. Thanks,
Matt

 

Matt, this is a good collection of great information. Have you had experience with any of these tires?

 

Likewise Matt, I appreciate the info. Personally (and I track about 20-25 days a year), I'm sticking to the OEM Pirellis for the moment. If I had a trailer, from the options you posted, I'd definitely go with the R888's as a second set.

Does anyone know how the heat cycling works with the R888's? I ask to figure out if they can be driven to/from the track without using cycles.

 

KonaKai, according to this page on Tirerack, Toyo does not recommend the R888 for highway use. You probably need to get a trailer.

I do not want to invest in a trailer yet, so I went with PSS so I can drive directly to track.

 

Too bad 18" wheels won't fit on the 991. Way more tire choices and less cost too!

As far as issues with the ABS, the actual diameter isn't as important as keeping the rear tire diameter a bit larger than the front.

 

I think I read it somewhere that it is not recommended to use anything apart from 20" with PDCC as it is not running properly then? Thoughts / opinions / prooflinks more than welcome. Thank you