403portside

Anyone else noticed this? Or maybe I'm mental. Thinking about upping the pressures a bit was curious if anyone else felt they were a bit soft feeling at factory PSIs.

Also, any bay area drivers here notice that on hwy 280 (say between SF and San Mateo), that the grooved pavement leads to a bit of wandering. Nothing major just a tad bit of side to side sensation from the groves and the grippy tires.

Thanks in advance for the feedback.

ADias

The southbound section between SF and Woodside is bad overall. The northbound side is decent.

Bad roads all around. There should be a gas tax lock-box to guarantee that the funds paid to maintain roads are not used elsewhere. Also, Caltrans needs serious oversight.

403portside

Totally agree. I'm appalled at how bad the roads are in general. SF in particular sucks.

91469972

The dealer set mine @ 33 46

ADias

Well he is off, as he actually tried for 36/44, but that is the full load (4 people and full luggage) setting. 33/39 is about right.

scb997

I've had the PSS's on my 2009 C4S for a little over 5000 miles. I've been sticking with the "full load" pressures - 37 front / 44 rear (cold, in the morning). Interestingly, in the morning when everything is "cool" (well, 75F this summer), my mechanical, electronic, and TPMS all say 37/44. If I read the pressures, for example, mid-day during an autocross, the three reading vary greatly. I suspect that the mechanical is the most accurate and the other two are trying (poorly) to compensate for the temperature?

My impressions of the PSS's - they are quieter and I feel I get a little better grip around the cones. WIth the expectation of longer tread life (this is the third set of tires on this car), the PSS's are a definite keeper.

The one pattern that seems to be emerging is that my fuel mileage has dropped. The C4S is my daily driver and I drive it a LOT. I've always averaged 23.0 mpg over the 10k mile service intervals. It really looks like I'll be averaging 22.0 mpg over this 10k interval.

Scott

sfrank

Dealer set mine to 33/44.

403portside

Update: set them to 35/41 and car just feels much more surefooted than before. I like it.

yossarian

Thanks about what I Target. The issue is the heat conference because I live in the city. If I'm out and south, or north I drop those numbers by 2. On a spirited drive I drop another two and make up for it with hot tires.

I don't really trust the gauge and while the old school cheap stick works it is a pain. I am thinking of getting one of those fancy release digital ones.

Zeus993

Let us know / pic of what you get... Mmmmmkay?

docjohnM

The "mushy" feeling is probably not your imagination.
My first thoughts on the tires were: Boy the ride is smooth!!...the next thought is: kinda "dead" feeling on-center.

I made sure that I drove around a bit on my PS2s (10% tread on rears, 25% on the front) the day that I had the tires swapped. I wanted to have a clear picture of the traits they exhibit. The PS2 had a "knife edge" feel just off-center in the steering. You could almost call it "darty" if the 997's steering wasn't relatively slow just off-center.
So, I drove for 100 miles on the new PSS tires and put it away for the night. Next day, another 100 miles and then tried to get a feel for the tire. I had instrumented a few turns near my house and knew the entry and exit speeds. The PSS does have a bit of movement in the sidewalls before the steering loads up. After that, it takes a strong "set" and the steering feel is back and the response is excellent. The grip is beyond the PS2s. I was able to do some turns at 46-47mph that I used to do at 42 (sliding the whole way) with the PS2s. The 46mph felt stable. I also took some of the turns in a "ragged" way with choppy steering motions to see how forgiving the PSS is. I found that they are significantly more idiot-proof than the PS2's, which never suffered fools lightly.
So I would say that Grip is improved with the PSS tires. According to my old-time GTECH meter, braking is slightly better, but I did not note the temps when I took original readings, so you would be right to doubt that data.
Noise is not much lower with the new tires, but the ride seems much better. Impact sharpness is much lower.
The PSS tires feel less "hyper" than the PS2. Let's say it is less like Yoko AD08, and more like RE-11 in this regard.
Now I have 600 miles on them, and the traits above are still consistent. I have an autocross in the Meadowlands next week, so I will know more then!

ADias

Those rear PS2s were shot, and... hard. Moving from used/old tires to new ones always feels soft - the old ones were rock hard.

What cold (68F) pressures did you settle in? I bet 34/40 is the correct value.

kosmo

what tires are on '12 gts?

docjohnM

True, very true! They were rock hard and slippery. I noticed it more at lower temps. All my data and impressions were from the previous year when they had 5K miles on them. I even devised a test for impact harshness.....There is a stretch of pavement that I have near my house that causes the cupholders and dash to rattle if I take it at 50mph. It has always been that way since I got the car. I took the road on the way back to the dealer.......no rattle! All of my dealer visits have been in the summer, so I am assuming that temp is not a major factor.
In NJ, it has been mid to upper 90's since I got the tires, and the dealer set the pressure at 36/44 (cold). My old PS2s were about 3 PSI lower for the street. for Autocross, I added back the 3 PSI. Come to think of it, I think I got tire pressure advice from one of your posts a few years ago. I have a note on my computer for 33/39 psi cold, 34/40 warm. (maybe it was MDRUMS...I can't remember) Those values worked well.
I am pretty excited about the new PSS tires. If they last longer, and don't turn into rocks like my old ones did, I will be very happy. The wet weather grip has been outstanding as well.
I am getting a new POV camera for the remainder of the autocross season, I am going to see if I can find a good location for the Mic to pick up some tire sounds! I'll post it if it turns out to be cool!

ADias

For street use I would set cold (68F) at 33/39. On the road they will quickly rise to 37/43.