I've really enjoyed the ride quality on my 991s. I mainly do city driving and the car is very comfortable on our local roads. My pressures were 32 front and 38 rear. I saw some of the other posts here about mpg's and felt mine were a little low compared to others (I usually get 19 mpg in the city, no freeway). To improve this I increased the pressures to 36 front and 42 rear (door sticker recommends 36/44). Now I feel the ride is uncomfortably harsh and jarring and now I fear the dreaded rattles will appear. Do others have a similar experience? I'm going back to the old settings.

 

I use the standard pressure...33/41. 36/44 is full load pressure. I get 26 or so in the city and 31-32 on highways. non-sport mode.

not as harsh as the full load pressure.

 

Once again thanks rnl, didn't realize the full load thing,

 

go to the tire pressure "control pod" and enter that menu. There is a place to check "full load"..uncheck it and exit to check the tire pressure. you will see that you are +3 or so on each wheel. ....i purchased a ridiculously expensive tire gauge and find that it's really helpful as it measures pressure to tenths of a pound and i can set the tires exactly on each axle.

...my dealer lent me a manual to read while I was waiting for delivery...i think i read it about...a hundred times...i still pick up stuff when i look at it from time to time.

 

I ran 34/41 cold on the 997.2 w/19s. I was told at the track as soon as you approach 50 psi in the back you start to loose grip and that DE hot lapping (yellow) raises the temps @ 7 psi.

Fast forward to this car which is on 20s. It was delivered with 36/44 cold! The fronts were approaching 40 on a hot summer day and the rears were at 47-48 driving in town...? Seems too high right?

I lowered them down to 30/38 cold and when they warm up in town they read 34/42. My mileage is not as good as it used to be with the 3.6, but only just and I only have 1,500 miles. I read it takes 5k miles before optimal mileage is achieved.

But does anyone think 29/38 cold is too low?

Thanks,
DRP

 

I run mine at 36/44 cold and do not find the ride to be uncormfortable. I do have PASM on the car which I think helps quite a bit. I believe that the manual has two pressure settings, defined as "comfort" and "sport". The 36/44 pressures are listed as the sport setting.

 

I asked the dealer about the pressures they set when I picked up the car at 32 F / 38 R, especially when the label on the door showed much higher levels as mentioned in above posts.
Dealer said the pressures on the door label are for full load with cold tires and that they deliver the cars with comfort pressure. This can be monitored as mentioned above through the TPM (check the Owner's Manual for details).
At a DE event at Watkins Glen in May I watched as the pressure soared to near 50 in the back and pushed 45 at the front!

All the info needed is in the Owner's Manual. To be frank the tire pressure question is more complex here than I've ever seen it. For instance just to add complexity there is reference here now to partial in addition to full loads, in addition to comfort and 'standard / sport'.

After some time at the initial comfort pressure the TPM started to tell me I was under pressure (btw -1 and -3) despite not having changed anything. I recently set pressures to 35 F / 41 R to come somewhere in between and am enjoying the ride.

 

Would there be any technical disadvantage to running the tyre pressures at the maximum - ie full load standard F39PSI, R 45PSI???

 

I run mine 36/44 cold and find the ride quality is fine. I agree that porsche has made the tire pressure issue way to complicated. Read through the manual and I was even more confused.

 

Comfort Pressures on my 991 are 34 Rear and 32 Front, as per TPMS. Where are you guys getting these pressures from?

 

cold start in the morning mine is 36/44 and this is how my dealer set it up when I picked it up first time.

 

I lowered my pressures to 34/38. The car is much more compliant. When set at the higher pressures my car felt like my old 996TT with Pss9's.....a definite step back in comfort and tolerance to bumps in the road.