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PS4S feel mushy to me, too. Grip is great, but I can really feel the car push the sidewalls from side to side in turns. This can make the car not feel very planted sometimes. Kind of like the sensation of walking in mud. With each step, your heel might shift left or right and you don't know what will happen until you put your weight down.
I think I have been guilty of throwing shade on this topic. Sorry. For those who don't want to read back through everything that has already been written here ...
3K miles ago I replaced only the rears on my then 138K mile 2010 C4S. And immediately the car wouldn't track in a straight line and the handling was horrendous. This was the case until the car improved a bit at around 1400 miles. But the next day on a spirited drive I was left wondering if it was time to sell my forever car 8(
But there's more to add to the story.
When you see a major change in performance you (I) tend to focus on the last physical changes to the car. There was only one change ... the rear tires. I laid blame there. This the possible shade.
But 3K later the front tires shredded on the inside, on a high 100 teens day, 70 miles from base. This was almost 15K miles earlier than my MPSS fronts would have worn out, and the first time in 100K miles of stewardship that inner wear was at fault. A quick note here ... Tire pressure loss was gradual, there was no loss of control, the tire remained in one piece so there was no damage to the car, and overall as failures go this was a very tame experience.
Fortunately I was amongst a flock of Porsches (a gaggle?).
One person had a spare for a 996 that left a hair of clearance to my brake calipers. I carry a large bag of tools so swapping things was quick and easy. But having that spare was critical.
A few notes of interest on this ... I had never driven on a skinny spare before, when braking the car pulled to the spare rather than the other tire (that was showing metal on the inside as well), and while not fully comforting, the spare allowed me to maintain pace with the other cars. All in all, the spare was most impressive.
Another gentleman called ahead to his wife and had a set of front wheels with Conti tires from his 996 delivered to the hotel so I would be able to drive home that night.
I'm used to taking care of others, not having others take care of me. This was amazing. PCA has it right when they say it's not just the cars.
Anyway, I digress.
Two days later with new front tires but no time for an alignment I joined a couple friends for a spirited drive. My car was back!!!!
And the alignment came the next day. The front toe was very negative. Why? That is a bit of a mystery, but my tire mechanic not only tracks alignment, but also ride height. And the front of the car had dropped. The fronts had a very good reason to wear out early.
So a bit more background. AWD cars have different front strut geometry to clear the front axles. This causes stress on the upper strut mounts. This was realized when I took the car into my indie at 120K miles for the PDK service. I had the kitchen down to the studs and was a bit busy so I opted to have the Indie replace them. He then set the alignment to my specs (that give up some handling for the sake of getting more tread life). I suspect the car dropped a bit after this. Why? Dunno. Do the mounts sack? I've sort of ruled out sudden spring sack on a 12 year old high mileage car, and the strut mount is all I've got. So this may be what affected the toe.
So were the rear tires at fault? I suspect long lasting mold release. But 1400 miles of that? I'm looking for reasons. The concepts justifying the reasons may be flawed. FWIW the PSM light never illuminated.
The fronts were definitely going bad when the rears were replaced, although i wasn't aware of this. The alignment was off. I was in a rush when the rears were replaced and skipped the alignment. The roads are rough here but for 100K miles I had not been able to throw the alignment out. So what are the chances it was bad then? Anyway, I lack a data point.
Perhaps AWD with these new MPS4S tires makes changing as a set required rather than per axle. The undersized 996 18" tires were awful on the 250 mile drive home. There was over an inch of difference in the diameter. Again, no warning lights so the system was satisfied. Would a fraction of an inch between new and half worn tires matter? Maybe, but the MPSS never had a problem.
Maybe for any of you out there replacing strut mounts you should schedule a second alignment after a couple thousand miles.
Maybe it's time to refresh my all original (excluding front strut mounts) suspension (you think?!?!).
Anyway, I'm off on a spirited drive tomorrow with good tires and a fresh alignment. I am debating adjusting the DSC front shock calibration table before I go. Hmmmmm.
On another note, summer is a weird time to ask for customer support, especially from a European based company. But Michelin did get back to me to state that the compound mix across the tread is the same for the MPSS and the MPS4S tires. I can't vouch for the sidewall construction.
So for now I'm considering the recent past to be a blip that I will need to keep an eye on. In the meantime I think I am happy with the MPS4S tires, again. And back to that entire suspension refresh ...
Wayne, I suspect you would not have had all those experiences and nuances with a different tire.... just a hunch. Again, I never read so much varying opinion... and situational performance... from users of other tires.
Wayne, I suspect you would not have had all those experiences and nuances with a different tire.... just a hunch. Again, I never read so much varying opinion... and situational performance... from users of other tires.
I switched from some 10 year old Michelins to ps4s on my 2011 S. I am no tire expert and wish I could do a 'back to back' test with other tires but I did a track day at Laguna Seca and found tire pressure made a HUGE difference to how the tires felt. As soon as I got over 38-39 psi hot (per in dash numbers) they became slippery and had lot of movement. It was very noticeable in feel and lap times.
I am sure there are a lot of factors that play into this (temp, road, speed, etc) but that was the first time I got to really feel how pressure affects drivability. I am sure the autocross drivers deal with this all the time but it was cool to FEEL the difference.
I switched from some 10 year old Michelins to ps4s on my 2011 S. I am no tire expert and wish I could do a 'back to back' test with other tires but I did a track day at Laguna Seca and found tire pressure made a HUGE difference to how the tires felt. As soon as I got over 38-39 psi hot (per in dash numbers) they became slippery and had lot of movement. It was very noticeable in feel and lap times.
I am sure there are a lot of factors that play into this (temp, road, speed, etc) but that was the first time I got to really feel how pressure affects drivability. I am sure the autocross drivers deal with this all the time but it was cool to FEEL the difference.
That's what some of us found, even on the open road. These tires should never be above 40PSI, so the cold temp pressure must be set to guarantee that limit is not reached. PAG has done so by lowering low load 'cold' pressures on the 991 to 31/34. On hot days it may be necessary to start at lower numbers, something like 29/32.
I know I am in the minority here, as many in this forum still insist on cold 36/44. Nuts!
That's what some of us found, even on the open road. These tires should never be above 40PSI, so the cold temp pressure must be set to guarantee that limit is not reached. PAG has done so by lowering low load 'cold' pressures on the 991 to 31/34. On hot days it may be necessary to start at lower numbers, something like 29/32.
I know I am in the minority here, as many in this forum still insist on cold 36/44. Nuts!
It fascinates me how different the perceptions are of this tire. I am not surprised other theories emerge such as defects or differences from manufacturing locations. These PS4S tires are generally praised in the press for like all kinds of reasons. For me, I've resigned my opinions to that it is just one of feel... not performance... at least for my usage. I really don't know what to make of all of this.
Peace
Bruce in Philly (now Atlanta)
I agree- I drove a friend's 997.1 C4S with Bridgestone Potenzas, it was so sloppy compared to my 997.2 C2S with PS4S tires. I'm in love with my tires, but worried that a replacement set might feel completely different. I wonder if it's some subtle variants that people are getting? The "N" thread & video speaks to there being very different versions of the same tire (the BMW M4 vs. generic PS4S), maybe Tire Rack gets a different version than Discount Tires etc?
That's what some of us found, even on the open road. These tires should never be above 40PSI, so the cold temp pressure must be set to guarantee that limit is not reached. PAG has done so by lowering low load 'cold' pressures on the 991 to 31/34. On hot days it may be necessary to start at lower numbers, something like 29/32.
I know I am in the minority here, as many in this forum still insist on cold 36/44. Nuts!
Attached - 997 GT3 door tire pressure label:
Consider yourself to be a trendsetter who is in front of the curve. Consider the rest of us to be resistant to change and thus behind. Thanks for the input, again.
BTW ... I had my pressure washer and wash bucket arranged for quick set up, but with the waterless system I can have the car clean before I would have had it rinsed and ready to soap when i was using water. At this point I don't see myself going back to a hose regardless of how much rain we get next winter.
...
BTW ... I had my pressure washer and wash bucket arranged for quick set up, but with the waterless system I can have the car clean before I would have had it rinsed and ready to soap when i was using water. At this point I don't see myself going back to a hose regardless of how much rain we get next winter.
I hit a pot hole a couple of weeks ago and got a sidewall bubble. My back tires were just about on the wear bars, so I sprung for a set of PS4S on my 2011 C2S convertible with PDK. I had the N-spec tires on it. The car is a daily driver with about 70k miles on it now. I've had it about 3 years.
The upside of the PS4S is they have a bit less road noise and ride a bit more comfortably. The downside is they definitely don't have the turn-in or quite the authority of the original N-spec tires.
As a daily driver, I'm OK with that. They're fine for highway use and the somewhat reduced noise and nicer ride are good for commuting. I have to admit, going back to work and driving on California's crappy roads is grating and I wasn't enjoying the car as much, thinking something more comfortable and quiet might be nice. Kind of miss the original tires on the twisty mountain roads, but it isn't a bad tire.
That's what some of us found, even on the open road. These tires should never be above 40PSI, so the cold temp pressure must be set to guarantee that limit is not reached. PAG has done so by lowering low load 'cold' pressures on the 991 to 31/34. On hot days it may be necessary to start at lower numbers, something like 29/32.
I know I am in the minority here, as many in this forum still insist on cold 36/44. Nuts!
Attached - 997 GT3 door tire pressure label:
Okay, so when running lower pressures, should the gap in pressures be followed (I think rears are 7 pounds higher than the fronts on my door card) or the percentage difference? I started with keeping the pressure gap, reduced to 32 front & 39 rear last night to see how it feels on my 997.2 C2S, but that keeps the rears quite high per your comment.
When it comes to straight out traction, there is an optimal pressure for conditions.... less or more than this, the traction is reduced. Are we talking traction here or mooshiness? What is accomplished through "lower" pressures?
Peace
Bruce in Philly (now in Atlanta)
Last edited by Bruce In Philly; 07-23-2021 at 01:50 PM.
Okay, so when running lower pressures, should the gap in pressures be followed (I think rears are 7 pounds higher than the fronts on my door card) or the percentage difference? I started with keeping the pressure gap, reduced to 32 front & 39 rear last night to see how it feels on my 997.2 C2S, but that keeps the rears quite high per your comment.
3 to 4PSI Rear/Front difference cold, never 7. On hot days and that means when the tires are hot and the ambient temp (middle of the day is in the 90s - 29/32 quickly becomes 32/36 and higher still with spirited driving.
07-22-2021, 02:16 PM
