Spyerx

Hey guys - so the factory pressures are WAY too high. I'm used to running NT01 in the low 30s (like 32f/34r) HOT on track on my GT3. On street I run 29/33 cold which is factory spec.

I've been playing around on the 964 with 30/32, 32/34 and well, feels pretty good, very sharp, not mushy, and lots of grip, and on track I ran them about same as I run my RS hot. My buddy who is stupid fast and likes his car to slide everywhere runs them much higher. Me, I like grip (and am slower lol).

I'm curious what you guys like on these or similar R-Comp (100 tread wear) tires.

See ya

Matt Andrews

Interesting your friend is faster and likes higher pressure in NT01s. I've run this tire in competition on cars from 2000 lbs to 3500 lbs, and every time the they were fastest on low pressures (like you are suggesting, ~30psi hot). Much more than that and the heat distribution was uneven at higher temps. Are you (or he) using a pyrometer to understand what is happening with the inner/center/outer edges a different pressures?

Spyerx

I haven't run a pyrometer on these yet on track. So your finding is same as mine. I suspect I'm close as wear during track use is quite even. On street my camber is aggressive but such is life.

My buddy, he likes a VERY *** happy car. Driving it very momentum like and he's VERY fast.

Curious what you've found on street use? I run the same tires track/street on this car.

Earlydays

Interesting.....when I ran Hoosier and Kumho R tires for autocrossing on my C2 (with only aggressive alignment and corner balancing, since I ran in SCCA Stock classes) I found the car liked higher pressures and was faster. I did pyrometer measurements which also pointed to higher pressures.

Spyerx

do you recall where you ended roughly on pressures? A6 or R6?

Earlydays

I ran A6's at 35/36(F) and 39/40(R)

Bill Verburg

NT 01 33/34 hot they lose grip above that
RE71R same, but when used on the street I use that as a starting cold pressure(maybe a pound or so less) as they never get hot enough or need the max grip to start lower and build pressure.

Matt Andrews

Earlydays - how much temp increase would you see during your autox runs? It makes sense to me that you would start higher as much of your lap the tires aren't up to optimal temp unless you were using warmers.

I haven't spent a lot of time on setting up my 964. its still on stock dampers. Only modification is the E88's and NT01s. So I've simply set the pressures at ~33 / 36 and called it a day. I haven't pushed it hard on the street. I've had the intension of doing dampers, end links, camber plates, etc, but life has gotten in the way. Its a waste of a set of R compounds at this point...

They heat cycle pretty well, so maybe they won't be completely rock hard by the time I get them on track in the spring...

Earlydays

I would set the tires to those pressures cold and then bleed off air after the first couple of autox runs as the tires got warm and pressures went up a few pounds.


PS - I do run Bilstein HD shocks.

Spyerx

intersting on the hohos... on the NT01 they'll come up 10+ lbs on me after a session... so start first session mid 20s then bleed off until stable at 32/34 or so hot.

i agree with Bill they get loose above around 34.

Guess i'm in the ballpark here...

Sword_of_the_Spirit

You guys must have some comfy seats, no monoball, or can tolerate pain. Nor can I tolerate the stiff sidewall on the street. Given, my car is set up silly track. lol Kudos to you guys, but as hard I try, I can't build heat in em (set at 24f/26,27r) on the street at speed"ish." Track is a different story.

saysthesissydrivingasubarulegacyLwagondaily


post edit. I say the above due the fact I've even had issue with some of Sumi's most recent HP summer offerings. I may need to switch to a Michi Cup 2 or their sport 3 because the rear has come out when least expected more than once on a bog standard recent pave. Pretty sad to be honest. It maybe be time of day, driving style, or not get 15min+ of heat..... The Nitto's seemed to exacerbate the problem if not pushed like on the track.

If any of you have input, it's greatly appreciated. I'm figuring it's 99% the aggressive alignment.......