soulsea

So I'm on track next weekend and I was wondering if anyone knows the optimal cold psi front/rear for the SC2s on a 991 TTS?

Although it's for a different tire compound, I was going to take 5 or 6 psi off of what on the door sticker and go from there.

MaxLTV

on gt3, I'd start with 26 and 29, mostly because Michelin says not to drive below 26 psi. It's very low and it's easy to damage tires on the first 1-2 laps. But that ends up being high by the end of the first session, so i lower it more after it.

Turbo is 10% heavier, so I'd start 28/31 and be super careful for the first lap or so. But if you are not going for track record on the first session, you may want to start higher and go from there. Better end up with higher than optimal pressures than kill tires early in the day.

Gt3Fan

the cups2's are what you're looking for, there is no better. The trofeo's "may" be a slight bit better on track but wear much faster. Splitting hairs on track performance but way more economical with the cup2's due to better duration.

Karl911

SC2s are the only way to go. Trofeo"s and Dunlops both are marginally faster, both at 1/2 the life. at track i start at 26/28, hot 32/35

Randyc151

I agree.

I try to never, ever let tire pressure go above 35 on track. They get greasy after that, which shakes confidence. OP didn't mention the ambient temp, but on a cold day you should start out the morning at 28/30 and let the idiots pass you on the first lap or two while you build up heat and come in the paddock to bleed air if necessary after a few laps, ...then go catch them!

jbdmd

tracked my 991 TTS for the first time Friday. Only did about 18 laps at what felt like a 6/10 pace over the 2.75 Mile circuit at Indie Motorsports ranch. What do you suppose that is in tire wear? After couple track sessions do I need to re rubber the car? I'm running SC2's . The car is my daily driver, has 18000 miles on it and I replace the rears at about 10,000 miles. Fronts are original. Next track day is 4/30

Randyc151

I'd say that at 6/10 for 18 laps it's not going to be any considerable wear at all. You should be fine. My first season tracking I got about 12 full days at 7/10 or 8/10 pace for 4 or 5 sessions a day before I had to change the tires out, including driving the car on the street occasionally and to the track days a couple of hours away.

What tire pressure did you run at, and how high was it at the end of the session?

jbdmd

They have dedicated tech staff at the track and I think they took off about 15-20 lbs from each tire. I don't remember what they came up to hot. What should I be lowering them to cold on the track?

rcg412

Great tires. I use your exact same setup, 34/36 seem to work well.

Karl911

Here is what happens when you cut to close to the tiles with the small yellow curb on turn 7 hairpin at Sebring

Randyc151

Impressive!

Karl911

Randy,
You doing VIR on monday and tuesday?

Randyc151

Nope, heading up to Watkins Glen on Tuesday morning for Cups & Saucers with Hudson/Champlain PCA on Wednesday and Thursday. Let me know when you are coming next and I'll try to meet you there. I'd love to run with you.

Maybe David Murry in a couple of weeks!

Karl911

catch you next time

golfnutintib

definitely not

this is consistent with what many well trusted, harder-core trackers than me tell me

correct...

i would let them go up to 36 max front or rear on track... gets slippery at 37/38 and up in my personal experience

also, i believe some cup 2 automaker designations vary in terms of whether the tire has a curb edge protector, some others don't, as well as more subtle sidewall shapes (some straighter - like for a corvette z06, some bulgier/rounder - like for a 991 gt3)... i would imagine michelin's intent is to have this tire perform very similarly, if not identically, on any vehicle that they make the tire for...