snake eyes

Rather interestingly I was able to purchase Pilot Sport Cup 2's for less than (tire racks price) and $100 less than the 4s from discount tire...
So of course I ordered them, upcoming track day at Road Atlanta!
I've run OEM street tires on the track with the 991.2 S, yes the Pzero's... They were great to learn the limits of the car and not mask mistakes. yes, they are horrible but you still can have fun....
Anyways,
The GT3 guys are saying Michelin Cup 2s recommended street tire pressures are 29F & 31R (psi COLD). On the track they typically start the morning sessions around 25F & 27R (cold psi) and bleed air (as needed) to maintain close to 30-31F & 32-33R (hot psi) throughout the day. Most adjustments are in 2 psi increments (or slightly more on really hot days) based on the hot psi readings taken right after pitting at the end of a session. Do these pressures hold true for the 991.2's?

Tire pressures are important because I do not intend to replace these in under 2,000 miles... Also, I do HPDE about 3 - 4 times a year and canyon driving.
With my past cars I've run Bridgestones RE 980AS on my 997 and PZero on my 991.1, felt it was time to up the grip level.

I do plan on driving these tires on the street, I've read that they are no longer scary in the rain at all... just don't be stupid. Is this correct?
If I got the wrong tires coming, please share.

thanks
videos just for fun of the 991.1 - on Pzero's (sold the vehicle)

Dre01SS

Can't speak to your question (still hunting for my 991.2 C2S), but are you doing the Chin 4/16 event? If so I'll be out there with the family cruiser, look forward to meeting new Porsche folks

Stealth 993

Start pressures are tough, as there are so many things that change it. Honestly, on track with Cup's I find they start to go away around 35-36 psi. So target under that hot.
on my GT3, it feels better to run square pressure, my hot targets are 30-31psi all round.

snake eyes

Yes, I'll be there on the 16th

thanks for your feedback

enzotcat

Pretty much, yes. I have a 991.2 7MT C2S. On the street I run cold 29/32psi front/rear. It’s possible the GT3 rear recommended is slightly different due to a different engine weight and/or different size rear tire. For track I have typically started about 3psi below that front/rear. I have found that the moment the tires go above 36psi front or rear (and generally it’s the rear that’s the problem), they get greasy for that session.

Canyon carving - 29/32psi will be more than adequate unless you’re on a hot day. Regardless, you’re not going to be pushing hard enough on a canyon run to hit the limit of tire grip even if they are over 36psi. As to replacing them under 2,000 miles. YMMV. Don’t assume you’ll get that much if you do 3-4 HPDE sessions; depending on just how aggressively you drive, you may well get as little as 1,000 miles out of them.

Rain seems to be a mixed bag and different drivers will tell you different things. Some will say - fine, no problem. Others will say “sketchy AF, stay inside the house when it’s raining”. They're drivable, but not exactly confidence-inspiring. If you want a really confidence inspiring tire in the wet, that’s the Pilot Sport 4S.

Ecosse911

I run my Cup 2s at very similar pressures as stated above, never go above 35psi. Unless you take in to the dealer and forget to tell them to not mess with the tire pressures... Also after getting alignment at a well renowned race shop I left and immediately thought what the hell is up.. tire pressure was set at 40+ psi

In terms of wet weather performance, I have been caught out in the rain a couple of times (my car is not a DD). First time was up in the mountains and I thought well that’s the end of fun for today. Not so I was actually pleasantly surprised, however I did have low expectations based on others feed back. Bottom line you can still drive in the wet, just apply some caution or have a little fun

usccharles

i have found street driving at comfort pressures (29F 32R) to be perfect for me

for circuit driving, i usually start my first session at comfort pressure and bleed to 35F 35R Hot after the session. I know I can get more performance with a few psi lower, but sometimes it takes too long to warm up tires between sessions if you go lower than 35FR hot. I find 35F 35R hot will enable the tires to warm up quickly enough, even after long period between sessions for me to have enough hot tire minutes to enjoy each track session. i've found if i go below 35FR hot, the psi gets too low in between sessions, so i'll be spending most of my session trying to warm up the tires rather than really pushing laps. 35F 35R Hot is good balance to have good proper laps and minimal time wasted warming up cold tires IMH.

Stealth 993

New tires with light rain and over 60deg they are fine. It's when they get worn and it's under 60deg, that they are BAD, they are screechy AF. If it's really raining, just don't even try.

Right after I got my GT3 (new tires just installed) I drove to work to show my friends. It rained hard on the way home, on the freeway going straight, the car just changed lanes on me. I was just driving with traffic not doing anything. It kept hunting and moving all over the place. I took the next exit and hung out for a bit to lower my hart rate. I'm a avid track guy and do AX, so I consider myself an above average driver, this scared the hell out of me. Just keep that info in the back of your mind if it's really cold or wet, or both.

snake eyes

I got the tires installed... so far with street driving impressions... I can see why instructors ask you to wait until you get these tires.
The car drives like a go-kart on the road, excessive grip, I could easily see these causing over-confidence and mask mistakes on the race track.
These are clearly a track tire...I can't wait to get them out at road atlanta!

Speed2k

I'll take note of the feedback on here regarding the starting pressures for the Cup2s, for when I eventually use them on track.

Here's an interesting article on the Cup2s that I just read this weekend. https://motoiq.com/not-all-michelin-...ated-the-same/

AdamSanta85

Holy crap, if that wasn't the best sales ad for N spec tires I don't know what is...

97supratt

Hydroplaning, some cars do it and some don’t. I drove a small Mr2 spyder turbo on slicks in the rain and it didn’t hydroplane but my Porsche does. I guess that’s what 1k pounds of weight does in terms of tires.

911dude41

Fully agree, I have the exact same experience. Butt clenched on a long swooping connection between two highways that's over 100 feet in the air. I was stunned at the bite and mid corner grip because my expectations were so low due to rennlist posts.

There was also some light standing water on the highway, and the steering was very snappy. No skidding, hydroplaning or understeer. On a wide open 6 lane highway being the only car, I made sharper and longer tugs on the wheel, all was good. Tires had about 3k miles on them, not tracked though.

I am actually considering Cup 2 R's (Ferrari K1 size) and looked up this video. This guy says what coincides with my thoughts on wet driving.

stout

Hydroplaning is a good way to crash in a 911…of any generation.

Modern 911s are very light for how wide their tires are…which is what prompted the development of Wet Mode for the 992. Mainly, its presence is to give a driver a prompt to engage Wet Mode if he/she wants it on. Or to ignore it at their peril. Once engaged, it can do a lot to help keep the 911 driver who decides to follow the heavier 7 on skinnier tires down the autobahn in the rain—or pass it—only to find the 911 not so…grippy on the way into the offramp. PSM couldn't do much for those types of driver error. They were sort of a last frontier.

Of course, none of that helps 991 drivers.

As for hydroplaning, standing water is all that's needed (and not much) and type of pavement, road crown, low spot, etc all play a role—as do tire design, tire size, tread depth, vehicle weight, and vehicle speed. All things being equal, I'd take a Pilot Sport A/S > MPS4S > MPSC2 on a rainy freeway. I might go the opposite way on a rainy backroad with no standing water and enough heat in the tires—but there's always the risk of hitting a patch of standing water at just the wrong moment. But there's always risk in life. Only time I really had a scary run with MPSC2 was downhill on I-80 in a GT4 during a freak snow storm. Tires were well worn, too. Wet LA freeways weren't a treat, feeling greasy, but slowing down helped. MPSC2 was a massive improvement in the wet over the MPSC1.

Jony++

Hi, Thank you all for this information.

as the hot days are comming, I'm about to switch to M CUP 2 in my 991.2 GTS, and I have a doubt on the homologation.

There are no N0 for the Sport Cup 2, so which version shall I use? N1? or Connect? Thanks