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They need to be scrubbed off a bit as people above have mentioned but I think they also run better at lower pressures. I lost my rear in the first week running the pressures on the door taking an abandoned off ramp too hot. Once they were scrubbed off a bit, the same situation is no problem.
I posted this elsewhere but I run GT3 door card pressures because I am on GT3 wheels. Same tires on Lobster Forks and they were not as good. I experimented with pressures from the 29/33 range up to the 37/44 recommended C2S pressure on the lobsters. It cannot just be the difference in wheels. I think it is more the difference in pressure. I think the recommended pressures are clearly too high for newer tires. compounds have evolved in the last 15 years since that sticker was put on my car.
The indie I was going to was setting my pressures to the C2S door sticker and I would notice immediately something was off when leaving. They did this on 3 services even when I asked them to set things at 29/33.
I will set them a little higher for long trips, something like 31/35, so not really significant. I have NOT tracked these tires or my C2S but I do love the PS4S in the canyons!!
Tire pressures: Go do your own experiments.... just do it. Add 4 pounds both to the fronts and back.... then remove 8 pounds from the front and back. Take some higher-speed sweepers. Then go into a turn fast and do not let up on the gas.... your car will either under steer, over steer, or be neutral. Then add 2 pounds to the front... then remove 4 pounds in the front. If you adjust by one pound, you won't learn anything. Doing so, in bigger increments, you will learn. Just go do it.
Tire pressures in determine if PS2 or 4S are mooshy or not: Forget it. The difference in mooshyness between these two tires is so dramatic... IMO.... that tweaking pressures ain't gonna make one equal to the other. Again, just my opinion after back-to-back comparison.
Peace
Bruce in Philly (now Atlanta)
Last edited by Bruce In Philly; 09-27-2021 at 12:28 PM.
Tire pressures: Go do your own experiments.... just do it. Add 4 pounds both to the fronts and back.... then remove 8 pounds from the front and back. Take some higher-speed sweepers. Then go into a turn fast and do not let up on the gas.... your car will either under steer, over steer, or be neutral. Then add 2 pounds to the front... then remove 4 pounds in the front. Doing so, you will learn. Just go do it.
Tire pressures in determine if PS2 or 4S are mooshy or not: Forget it. The difference in mooshyness between these two tires is so dramatic... IMO.... that tweaking pressures ain't gonna make one equal to the other. Again, just my opinion after back-to-back comparison.
Peace
Bruce in Philly (now Atlanta)
One variable you may or may not have considered is that you went from a worn tire with maybe 3/32" of height in the tread blocks to a new tire with 9/32" of tread. There is obviously going to be way more tread deflection (mushiness) on the new tires (due to the taller blocks) even if they are the same compound.
I have these tires on 2 different cars. On my 997 I went from PS2s after a couple of sets, on my S4 I went from RT-615Ks. Both grippy tires. I drive hard, on the street and track. In my opinion, the PS4S is very comparable to both when run at the proper pressure and a good alignment.
Tire pressures: Go do your own experiments.... just do it. Add 4 pounds both to the fronts and back.... then remove 8 pounds from the front and back. Take some higher-speed sweepers. Then go into a turn fast and do not let up on the gas.... your car will either under steer, over steer, or be neutral. Then add 2 pounds to the front... then remove 4 pounds in the front. Doing so, you will learn. Just go do it.
Tire pressures in determine if PS2 or 4S are mooshy or not: Forget it. The difference in mooshyness between these two tires is so dramatic... IMO.... that tweaking pressures ain't gonna make one equal to the other. Again, just my opinion after back-to-back comparison.
Peace
Bruce in Philly (now Atlanta)
I've done this pressure experiment. I've been from 29 to 37 in the fronts and 33 to 44 in the rears. In straight lines lower pressure is better. But at low 30s the turn in makes me very insecure ... the tire seems to become an extra spring (sans shock absorber).
The MPS4S prefers lower pressure from what I've seen. But no matter what, I find this latest set to be, as you say, mushy. They do not inspire spirited driving.
But my first set was wonderful. What happened? When I installed this latest set the handling difference was immediately night and day (in a bad way).
So what is the difference? Is this a Covid manufacturing problem? Did they change the formula without changing the part number? Did something happen to my suspension at the exact same time my tires were refreshed? I went on a 500+ mile drive last Saturday and returned home most unimpressed. Why was everyone touting the early production of these tires and now so many are unhappy?
For a reminder (this has been a very long thread) we took a 2,000 mile trip the day after putting on new rears. Pam immediately noticed the car was jerking across the lane and I was fighting to keep it straight. At 1,500 miles it got a bit better. Then in spirited driving the next day it felt like a demon was in the wings just waiting for the right moment to toss us off of a cliff. Later I found the front toe had slipped and the fronts were damaged. So they got replaced. I thought the handling improved. But it didn't.
Yep, at 142K miles I've still got the original suspension. Once the budget absorbs the vet bills I'll be addressing that. But in the meantime, nagging in the back of my skull, is the fact that this negative change in the car occurred like a switch being turned on when only the tires were changed. I remain skeptical.
One variable you may or may not have considered is that you went from a worn tire with maybe 3/32" of height in the tread blocks to a new tire with 9/32" of tread. There is obviously going to be way more tread deflection (mushiness) on the new tires (due to the taller blocks) even if they are the same compound.
I have these tires on 2 different cars. On my 997 I went from PS2s after a couple of sets, on my S4 I went from RT-615Ks. Both grippy tires. I drive hard, on the street and track. In my opinion, the PS4S is very comparable to both when run at the proper pressure and a good alignment.
My summer tire order: Continentals->PS2N->PSS->4S->4S->PS2N
Given your concern over tread block... well the PS2 N should have performed worse as the 4S was worn and the PS2 had high tread blocks... but even with this disadvantage... including mold release grease... the PS2 N were stiffer and tracked better.
Further... I did not report on the PSS as my memory was not good. I do remember liking them very much and was way impressed with the mileage I got from them. I remember when I moved to the 4S I was very hesitant. Why move when the PSS were so good? But I was a sucker for YouTube and all the online raves.... so when I moved to them, I was not happy right out of the box.
Wayne: Why were your original set better? I dunno. My first set way back when they came out were mooshy. I never liked them. So why did I buy a second set? I was continually pulled by the online reviews... it was emotions, not intellect. Could you have been swooned by the reviews at the time? They really were just nuts over the moon with these tires. Just asking.
I'm not denying anything, including being influenced by others!!! I haven't got answers but I do have a scientific background. In this case, the uncontrolled variable is me 😀
This seems very odd to me, all these issues with these tires. Granted I just bought my first 997.1 C4S a week ago but I put about 300 miles (very spirited) going up and down HW1 and along some very twisty roads in CA, and the car is on rails. Tires are 3 years old, and pressure at 34 front and 42 rear cold. I could not be happier with the performance. Car is stock.
Maybe it's a bad run of tires, but I find that hard to believe with Michelin and the safety risk inherent in high performance tires.
This seems very odd to me, all these issues with these tires. Granted I just bought my first 997.1 C4S a week ago but I put about 300 miles (very spirited) going up and down HW1 and along some very twisty roads in CA, and the car is on rails. Tires are 3 years old, and pressure at 34 front and 42 rear cold. I could not be happier with the performance. Car is stock.
Maybe it's a bad run of tires, but I find that hard to believe with Michelin and the safety risk inherent in high performance tires.
I am not sure what you mean by safety issues. Please describe.
Regarding my posted opinions, I never felt the 4S had any safety issues at all. Further, I do believe the YouTube tests that show the 4S has more grip in many situations. I just don't like their flexible side walls that result in less fun... less feel than the built-for-Porsche N spec PS2.
Tire pressures in determine if PS2 or 4S are mooshy or not: Forget it. The difference in mooshyness between these two tires is so dramatic... IMO.... that tweaking pressures ain't gonna make one equal to the other. Again, just my opinion after back-to-back comparison.
Peace
Bruce in Philly (now Atlanta)
My comment re tire pressures has nothing to do with the tire mooshy feel you and others find.
Tire pressures (for the most part) are the same for all different brands for the same tire size in the same car. I simply pointed out that PAG drastically lowered tire pressures in the 991 and this in a car that by design is far cushier than a 997.
I decided on the PS4S tires and ordered them in early August. They were not in stock anywhere - on backorder. The fronts came last week and the rears are supposed to be in this week. (The order was arranged through the local Porsche dealership here.)
The car currently has a set of PS2's.
With all of the comments in this thread, I'll be especially curious to see how the PS4's are.
I am not sure what you mean by safety issues. Please describe.
Regarding my posted opinions, I never felt the 4S had any safety issues at all. Further, I do believe the YouTube tests that show the 4S has more grip in many situations. I just don't like their flexible side walls that result in less fun... less feel than the built-for-Porsche N spec PS2.
Peace
Bruce in Philly (now in Atlanta)
I am not implying there are safety issues at all with the tires. What I mean is tires go through a rigorous QA/QC process. In my opinion as part of this process I would think any flaw would be detected. That's all.
It’s interesting that the PS4S are Porsche N spec approved for the 991, but not the 997. Wonder why. There is a difference in terms of the weight distribution between the two models cause the 991 has the engine shifted forward ever so slightly (couple inches I think) versus the 997 which really hangs back there. Wonder if that has anything to do with it.
It’s interesting that the PS4S are Porsche N spec approved for the 991, but not the 997. Wonder why. There is a difference in terms of the weight distribution between the two models cause the 991 has the engine shifted forward ever so slightly (couple inches I think) versus the 997 which really hangs back there. Wonder if that has anything to do with it.
It’s interesting that the PS4S are Porsche N spec approved for the 991, but not the 997. Wonder why. There is a difference in terms of the weight distribution between the two models cause the 991 has the engine shifted forward ever so slightly (couple inches I think) versus the 997 which really hangs back there. Wonder if that has anything to do with it.
PAG does not usually go back in car gens with updated tires. The PS2S was the last Michelin rated tire for the 997. It is an old tire design and it was already used in the 996 gen. It is a hard and loud tire as it ages.
Tire pressures: Go do your own experiments.... just do it. Add 4 pounds both to the fronts and back.... then remove 8 pounds from the front and back. Take some higher-speed sweepers. Then go into a turn fast and do not let up on the gas.... your car will either under steer, over steer, or be neutral. Then add 2 pounds to the front... then remove 4 pounds in the front. If you adjust by one pound, you won't learn anything. Doing so, in bigger increments, you will learn. Just go do it.
Tire pressures in determine if PS2 or 4S are mooshy or not: Forget it. The difference in mooshyness between these two tires is so dramatic... IMO.... that tweaking pressures ain't gonna make one equal to the other. Again, just my opinion after back-to-back comparison.
Peace
Bruce in Philly (now Atlanta)
I took my '07 C2S to the track last weekend with newly mounted PS2 N2 rubber after the PS4S ruined my last DE event because of the "mooshiness". You are right-it made the car scary to drive in high speed (120 MPH +) straights and turns. I had no idea what pressures to use so I did what you are suggesting-I measured before and after session pressures with a good gage. After adding 4 psi, taking out 2 psi, etc. I found that hot pressures of 43F/49R (37F/42R cold) worked the best. This surprises me because most people here are talking about much lower pressures than this. I did wear out the shoulders on the outer edges of the driver side tires but I think this was due to my sloppy driving technique.
09-27-2021, 01:10 AM
