Amalgam

Got my 991 with 20" delivered about 1.5 months ago and according to dealership, the vehicle is calibrated up to specs.

Just checked the tire pressure on the console: 30 PSI front tires and 39 PSI Rear - while the sticker on the door says 36 PSI front and 44 PSI rear. Approx. 5 PSI difference on all tires. Is there a reason to that or I should inflate to recommended PSI on door? What is your tire pressure?

GSIRM3

Tire pressures listed on door sticker are for full load conditions. If your car has been driven before you read the pressures on the display, then your cold pressures will be lower.

MayorAdamWest

I've been playing around with mine recently, after discovering they were way too high at the track. I'm currently at 31/34 cold which is definitely a smoother ride, and provides better traction. I've seen some people with more like 30/33 cold. I'm not sure I could tell the difference in 1psi, but coming from 36/42, it's a big difference.

naaranha

I am going to include some links...I would keep the pressure the way it is. Ideally you should measure the cold tire pressure at a temp of 68F. Look at comfort tire pressure vs pressure required to go over 165mph. If you dont track, keep it at comfort pressure.

http://www.porscheownersmanuals.com/...ssure%20pg.107

http://www.porscheownersmanuals.com/...6/262/Pressure

http://www.porscheownersmanuals.com/...-manual/6/263/

Hope this helps!

GT325

Even if you do track comfort pressure maybe appropriate........

TTCarrera

For my C2S with 20" wheels:

If I've read the manual correctly, I have I it set for Partial load (because I'm not carrying 4 passengers and the trunk is not filled to the top with rocks) and Comfort (for sustained speeds below 165mph).

At the above settings I think it says 31 psi Front Axle and 34 psi Rear Axle.

barihunk

Went back and read a bunch of threads and I think the general feeling is that most of us should be running comfort pressures since we're unlikely to exceed 165mph during regular driving. I'm sure it's somewhere but I'm not sure how much weight exactly full and partial load means.

What really isn't clear to me is the relationship and the best compromise between tire pressure and grip, handling, suspension wear, tread wear. Curious.

John 996 TT Cab

The various settings are in the manual near the back. I have used Comfort full load (the ones above look like comfort part load). Obviously I'm not using the pressures for the very high speed ability.
I think mine are about 30-39 or so cold.

MayorAdamWest

Beside that, if you're exceeding 165 in North America (not the Autobahn) then you should be on a race track, in which case you may even lower it more than the comfort setting, as your tires will get quite hot. I suppose the exception is for those drag racing.

TTCarrera

For reasons known only to them, they don't define Partial or Full load.

One way to tell for sure is to stop driving, jump out and measure each tire's temperature with a pyrometers or infra-read thermometer. If the temperature of the inside tread, outside tread and 3 spots in between are all the same, then your tire in perfectly inflated for maximum traction and stopping power.

If the temps in the middle are higher, the tire is underflated ( the centifigul force balloons the tire) and the contact patch is best in the middle. And vice versa for over-inflation.

Dr.Bill

When I had my 991 C2S, I just used the comfort setting of 31/34 cold. Worked perfect for daily driving. It was also the perfect starting point for track days - the tires got to the optimal hot temp with that starting point.

GT325

See attached picture for closest thing to "definition" of full vs partial load.

I find the ride with partial load comfort (31/34) f/r to be night as day improved for daily driving and it will also be my starting point for my first track day with my C2S. My 991 was delivered with full load high speed pressures and the ride was very clearly less compliant as a daily driver.

solomonschris

My tires, P Zero oems. are just terrific. They are crap in 35F and under, the're not so great in the rain, so I'm interested in the opinions of those that must drive in the rain a lot. For me the pressures are insignificant in that all pressures yield traction limits beyond which I will ever probe on public roads. I'm after a tire that gives signals prior to letting go, that is not noisy and will last 10K on the rear. The best solution will be a $57 dollar tire.

chuckbdc

At 12 months: 32 F 36 R (cold) on 20inch P 0s and even half worn at 12 k street miles, not pushed all the time, no track.

parkerfe

I've been running 33psi-front/36psi-rear in my 991c2s for 16k+ miles since new in June 2012 and have been pleased with the feel/handling.