Porsche-Suchtig

I’ve made the decision to go back to the track for DEs only. After 5 years free of wheel to wheel racing I think the risk of relapse is low. 😬

I am thinking about using the stock Cup 2 tires for track duty. I know they are slower than the other options. I’m more interested in longevity for DEs.

Anyone know how many heat cycles you can get out of them before they turn to junk (lose most of their grip)? Alternatively, about how many track days can I get out of them?

TIA

GrantG

I typically corded them before heat cycles were an issue - about 3 days (maybe 80 minutes per day), but second half of 3rd day is usually not great.

Porsche-Suchtig

Wow that’s a bummer. I was able to get more life than that out of the Pirelli slicks on my cup car.

Where were you cording them?

Palting

There are some who will go for that last fraction of a second on a timed lap, shave their MPSC2s, and those say it loses grip after a day or two at the track. Maybe it does, maybe it doesn't. I run until I cord the tires, which is max 9 DE days in the red run group at Mid-Ohio, Watkins, Road America. That's usually 3 open track days, the rest of the days about 90 minutes each day. I used to go to Pittsburgh International as well, but that track is hard on the tires, cord them after 3 days or so, and I figured not worth it.

One caveat on the MPSC2s. There is a tendency to wear out the outer edge and not make 9 DE days. Some, like me, have tried to counter this with more negative camber. Doesn't work, and I believe it was Trakcar who went as far as -3 camber, and only succeeded in slowing his lap times while still wearing out the edge. I've since switched to the Dunlops. More even wear at -1.8 camber all around, less greasy if I overshoot the optimum tire temp/pressure, and can get 7-9 DE days depending on how many open track days.

ipse dixit

No more than 20 heat cycles.

Also, with my 991.1 GT3, the front tires tread tended to wear out before they heat-cycled out, and the rear tires heat-cycled out with plenty of tread still remaining. I suppose this is expected with a RWD - rear engine setup, but it seem exacerbated with the Cup2s.

Porsche-Suchtig

I used to be one of those guys. I’d use one set of new slicks for no more than one race and two qualifying sessions. (I would cycle the old ones through a few more times for practice.)

Can I ask for clarification on one thing? You said they lasted about 9 DE days but then also said they last about 3 open track days... why the difference?

How do you like the Dunlops? Which Dunlops are you running? And how many days are you getting out of them? (Sorry for all the questions. I haven’t run a DOT r compound since the early 00s.)

Palting

You must have been open racing for a while, with with no time for DE. . The DEs I go to are usually a 3 day weekends. First day being open lapping ,means run as long and as often as you want., The other 2 days have run groups divided into experience, with each run group having about 3-4 runs of 20-30 minutes each. So, in my statement, 3 open lapping days are included in the maximum of 9 days to cord the tires on the tracks I mentioned. If you are referring to cording the tire after 3 days only, that was at Pitt Race where the track surface and configuration just kill the tires, so I don't go there anymore.



I use the Dunlop Sport Maxx Race 2. These are the other OEM tires for the .2 GT3. As I noted in the post, I can more easily get a maximum of 9 days before they cord out.. I still bring another set of tires, because sometimes I really get into it and cord the tires before i get to 9 days.

EDIT: As an aside, I have a lot of friends who use 19" wheels and get used take-off slicks from racers for cheap. Might be an option to you, using your wheel to wheel racing contacts

GrantG

Outside shoulders (rears go first) - was told that Rear Axle Steering accelerates wear there (even with alignment).

BTW if you're just a little bit slower/cautious, you can dramatically increase life. If you are near the limit, the tires wear exponentially faster.

I also switched to Dunlops - last slightly longer and less fussy about pressures. Cups have a softer compound on the outside shoulder of the tread, while Dunlops have one uniform compound across the tread.

Porsche-Suchtig

Got it thank you.

As for careful and cautious, I’m not very good at that! 🤣

Porsche-Suchtig

Wow that’s a s—t load of track time. As for track days, the last time I did one was in my then new 996 GT3. I was racing ITS at the time but wanted to see how the GT3 performed. (It was a blast.)

I thought about slicks but I don’t want to be changing wheels/tires at the track since that means also having a tow vehicle. It’s a slippery slope. I’m also not wild about potential warranty issues. If I recall right, Porsche claims they will void at least certain aspects of the warranty if using slicks. My main concern is the 10 year engine warranty. I could see “higher g forces from slicks” as a possible reason for not honoring the warranty. Idk maybe I’m overly paranoid? 😅

M3the01

Where are these 3 day DE events? Havent seen anything in the bay area past 2 days,

DHI

Good first hand info in this thread.

For reference, the good folks at ApexTaxi in Nurburgring applaud the Cup2 as their tire of choice for their GT car and say they can get up to 90-100 laps or something like that.
I find that promising.

So much so that it was worth doing some math...
90 laps x 8 minute/lap= 720 minutes total
720 minutes / 20 minute DE session = 36 heat cycles

That's a lot in my books and would be quite happy to get that while hustling around a track at a fun decent pace.

Palting

You are welcome to come to the Midwest at any time. Check out the PCA clubs of MidOhio Region, North Ohio Region, Northern New Jersey Region and their DE schedules. There’s even a 4 day weekend coming up with the Northwest Shelby Club at Road America in June. It’s a Shelby Club but all makes are welcome. Thursday and Friday are all day open lapping, and people leave after Sunday morning, so Sunday afternoon converts into open lapping as well. Better bring extra brake pads and tires!!

wmond

9 or 10 DE days for me. White group. That’s at about four 25-minute sessions per day. Erko Will only get 2 days out of his tires, but he’s much faster than me. Last day or 2 they noticeably start to lose grip.

WP0

MPSC2 is a good track tire, but, as mentioned above, they become quite "greasy" once you exceed 32 psi. I drive in the advanced driving group, and I've run them where I only get 4 track days out of them (they cord on the outside if you run the tire pressures too low, which is what you need to do if you expect to keep the pressures below 32 psi during the entire DE session). I've also run them about 10 days, which they easily last if you don't drop the pressures too low, but by mid-session they're running 35 psi; however, they do tend to heat cycle out quite early, but it's still fun driving with the back kicking out around turns!

I haven't tried the Dunlops, but perhaps I'll do that next. . .