Land Jet

Just bought my first set and need feedback from you guys. My car is pretty heavy, 2002 996TT. From what I have read so far, it seems there is some controversy about the proper pressures for these tires. What cold and hot psi has worked for you?

TAI2

I have a new set as well and trying out different pressures. I have a 993 and found that 34/38 cold worked out well at Watkins during a partially sunny day at 58-65F. The post run hot pressure were 40/45. As the days got warmer the hot pressures went to 43/50 which is too high as the tires got very greasy. I'll start out with lower cold temps. During a recent AutoX, it was very sunny and in the upper 70's. I needed to start at 32/36 otherwise the tires got too greasy after 3 runs. Hope this helps.

Bill Lehman

Initially, driving a Cayman, I was running 36F and 38R hot. Toward the end of the session, the tires started to feel a little loose. At my last event at Lightning I tried going the other direction and found that 32F and 34R worked well and semed O.K. for the entire session. Finally ran 31F and 33R with good results. Earlier I had tried 40F and 41R hot and didn't feel an improvement over 36F and 38R. In general, pressure gain from cold to hot was about 8 psi.

cobalt

I found if i exceeded 40 hot they got very greasy. Optimum for my 964 seems to be between 34/36 and 36/38 hot F/R.

boss351

996TT here also on my second set of R888's. I really love the grip, longevity is pretty good (5-6 track days depending on how many laps and aggresiveness).

Cold depends a lot on ambient. Hot I aim for on average 38 front and rear. Longer (open track sessions) be most wary as they will get greasy if you let the hot pressures get higher up there. A decent starting point cold is about 32/32 and checking hot right when you pull off, I drive on normal pressures to/from the track.

mark kibort

maybe Seth can chime in and give us a ball park of what pressures they run in WC on the tires.

I know the RA1s were in the 28-30psi cold range, but they are a little different.

boss351

I thought this had come up before, take a look at this thread, some good data points there.

BobbyC

for your car, 38R and 36F - hot

997gt3north

on a cooler toronto day at mosport for a 25 min DE session i start cold (clockwise track)
fl= 27, fr =28
rl= 27, rr=28

hot usually gets
fl=fr= 33
rl=rr=35

personally, i think fronts need to stay below 35 for best grip

hotter days, longer session, i reduce starting tempts by another 1, 2, 3, etc degrees

a hot day at VIR, tires go up 10psi

tkerrmd

Larry I start 30 front 32 rear in am and still let air out as the day goes on especially the rears. they need to be kept at 38 40 would be a max. they are a great tire have fun!

Land Jet

Thanks guys, appreciate the input.

trackjunky

Be very wary of tuning your tires simply by pressure. You should always use a temperature probe and balance out the temps with the pressures and alignment.

Here's a case in point. I said that my R888's were best over 42 psi, but many told me that was way too high. They run like 37 or 38. I ran 37 and my temp guage was showing under inflation and the tires didn't seem to be grippy enough.

I was then told that I should look to sway bar adjustments as I had over adjusted due to the temps I WAS running before. So, off to adjust the sways. Nothing improves.

Then, someone borrows my pressure guage and thinks that something is wrong with their guage because the pressure increased since the last reading. We tried three different guages and the variation between the three was around 3 1/2 psi, with mine reading the highest. We finally determined that the lowest reading gauge was actually the most accurate.

So, moral of the story is that for me 42 psi hot is perfect. But...my gauge reads 3 1/2 lbs too high. So maybe 38-39 is correct.

Use a temp probe and dial pressures in that way.

mdrums

Larry, Toyo recomends anything from 32-38max hot. for your heavier car I would suggest 36-38 hot.

On my 09 997S at Sebring I have to start out at 27 cold to get to 38 hot all around and I adjust/bleed through out the day.

333pg333

Seems to be a lot of conjecture on these tyres, perhaps due to different cars (weight / setup / style etc). I'm pretty sure Toyo (US) suggested a hot psi in the high 30's but then released new suggested psi rating in the low to mid 30's. Sounds like trial and error still....