Supercharged111

My last run of the day was with the tires at 26F/24R and I'm still not hitting the triangles. They're howling through the turns, so I'm fairly confident it's not my lack of skill/motivation to blame, so what have you guys found? I'm running 295/35/18 all around on a mostly stock C5Z. As far as I know, I'm running low 1:50s at Pueblo Motorsports Park, which probably means nothing to 95% of you.

hklvette

I know its a bit apples:oranges, but for auto-x I use 30psi hot all around, and I do get near the triangles. The thing with NT-05s is this: they DON'T work at high (or even medium) slip angles. Its been my observation that the compound is "hard" to the touch even when hot, but gets "tacky" when they get up to temperature, yielding better grip. You can tell when they're hot because they'll pick up pebbles like race tires will, but if you watch they don't "sink" into the tread.

my $.02

JeremyGSU

Sounds low to me.

I run Nitto NT555 RII's and start the day with 30F / 28R.

c4cruiser

I would start with at least a couple psi more for cold pressure. Start with maybe 28/26 or even 30/28 in the morning and then try another 2 psi the next time.

I run NT-05's in 275/40-17 on my '87 for track days and I usually start at 32/30. The car is set up more for autocross than track use and I use A6's for autocross events. The NT-05's do take a couple laps to get enough heat in them to become sticky.

Vettechris996

Not sure if this is going to be much help but I used to autocross on NT05s and I was keeping them around 28psi hot. They felt way better with the lower pressure but overheated faster. I was surprised how much better they felt so you may not be out of the ball park with having lower pressure than most people expect.

blkbrd69

Liked my C6 NT-05's at 32 hot. Had to start at 24 to keep the pressure that low at Sebring.

hungryhippo

I have 2 track days on mine and they felt the best at 35psi hot... but I did manage to wear out the centers of the tires pretty bad. So I will try much lower pressures next time.

MX621

Njmp thunderbolt 30f/28r hot ran 1:39 first time there with chicane. Pretty predictable/controllable oversteer.

Supercharged111

I haven't checked my hot pressures yet, I'd forget until the car had sat for an hour. Your numbers are encouraging to me. Were you going based off of feel or hitting those triangles? I think I've got zero wear after 1 weekend, they're rather brick like. I can't tell if they're better (front) than what I had (RE760) because they're not as good as I had hoped, but the balance has definitely shifted some. It's odd to describe. The rears were previously bald but seems to hook better with these (new>old), and since the front seems to bully the car around just a little more, I'd have to say they are and I'm just not used to them yet. If they're quiet, I'm going too slow. Never had a tire that loves to scream so much.

bluemagoo

It was pretty cool at PMP yesterday. As I recall, maybe 40* in the morning and probably not much past 50* even in the afternoon. Not quite the optimal temp for these types of tires.

I went through a couple sets of NT05s on my C6Z and generally started around 28/27 cold if the ambient was 70*F or so in the morning (garage). I aimed to keep the hot pressures approx 32-33* and so might have to let out a little air as the day heated up to maintain that pressure.

(Edit: I should add that the above tire pressures were obtained with a t.p. gauge rather than from the DIC. I've found that the DIC always reads 2.5-3.0 psi lower than the hand-held gauges and believe this discrepancy may be due to the altitude here in Colorado and the differences in how the TPMS and the t.p. gauge obtain the msmt.)

Supercharged111

Were you able to hit the triangles? That's really all I'm basing my pressures off of. Starting to wonder how wrong that is. I wore the centers out of my RE760s by running too high of pressures and I don't want to do that again. I'm more concerned about even wear than overall traction at the moment. Or is it the fact that the track was too cold to heat the tires up so they'd grip enough to roll over? It seemed like they came alive that last session, I felt the grip change over the course of that 20 minutes. Same with the brakes, I definitely got the necessary heat into them.

bluemagoo

Yeah, the triangles are what I used for a reference and added/ subtracted pressure in each tire if needed throughout the day.

SG4206

You know already that tire pressure is very subjective to car set-up ; so - try a laser temp gun.
Jump out of the car after that last lap , and read inside ,middle and outside temps. You might be surprised how far off your pressure's really are.

Supercharged111

If anything, I'd use a probe. I know a guy I can share with next time. Laser temp gives you the "right this instant" readings, whereas the probe gives you an "over the course of 20 minutes" reading. I realize pressure/feel can be subjective, but I'm just after even wear at the moment. With all the 30-32 hot mentions, I've got to wonder if I'm missing something.

RallyeChris

I just spent 3 days at Watkins Glen. Started the weekend at 38psi hot. No good - especially at the to pof the Esses. Felt very unstable. Bled-down to 35psi hot. Still not ideal. I settled on 32psi hot. Felt great there. I had them wearing right at the triangle in the front. Rears still about 1mm high of the triangles. Running -1.5* neg. camber up front, -1.2* neg. camber in rear.

Supercharged111

I don't know what the buttometer should register when I get the pressures set right. Some say ~32 hot and others have liked ~38 hot. 38 seems high, like tear the centers out (again) high. The car now runs a square setup, so as far as feel goes it's all kind of new to me. The front end seems a little more authoritative now, under braking too.

Dirty Howie

I have been using them for at least 3 years now. I like 34F and 32R HOT. I do hit the triangles.


DH

Supercharged111

Here on the CF, the concensus is statistically in favor of low 30s hot, so that's good. I saw where some S2000s, Miatas, and even a yacht of a GT500 were liking the higher pressures. I guess I'll just forget I ever read that, especially when someone who's ran them for 3 years has settled on the lower pressure.

FASTFATBOY

I have a much heavier car at 3800lbs but I start the session with 31f/26r