I don't remember.... I am getting old! For winter tires, I usually run 1-2 pounds more in fronts and rears over spec. I do this for a few reasons:

1 - Philly winters can have big tempurature swings and I don't want the cold dips to result in under inflation and TPMS warnings going off. I don't like adding pressure in freezing weather... no fun.
2 - Winter tires tend to have mushier handling and adding a bit more pressure seems to firm them up just a bit.

Opinions on my tactics?

Peace
Bruce in Philly

 

Depends what you mean by spec. Dealer just inflated my tires to 37/44, even though the manual clearly says the spec is 33/39. Also, if you check the manual, there is a pretty big shift in pressure due to temps. 33/39 is for about 70 deg. When it's 30 deg, the pressure should be several pounds less. A chart is in the Porsche manual.

 

Interesting comment..... so I dug into my manual and found some interesting stuff I thought I would share. 2009 C2S

Pressure increase as the result of
temperature increase
In accordance with physical principles, the air
pressure changes as the temperature changes.
The tire pressure increases or decreases by
around 1.5 psi (0.1 bar) for every 18 °F (10 °C)
change in temperature.
The Tire Pressure Monitoring takes this relationship
between tire pressure and temperature into
account.

I wish my wife's Lexus took this into account as she freaks out when the temp drops and her dash lights up.
I could find no chart in my manual although, there was a page showing pressures at 68f for loaded and unloaded weights.

Peace
Bruce in Philly

 

I'll have to check again about the chart, maybe it is for turbo owners only
Good stuff about the temps though, right? I just hate that everyone does the pressure to the door tags when they are incorrect. Also check in your PCM display. If you go to tires, then info, it will display the appropriate pressures.

 

Had the Continental T810S N rated, now switched to non-N rated Dunlop Winter Sport 3D, all on original 19" turbo wheels on a 2007 997TT.

Very happy with them going into the 3rd season, very low mileage though.

 

Also when you switch to Winter Tires go into the PCM and change to Winter Tires.

 

Sottorzeros N2 are great here in Colorado!

 

I just drove in that NJ snow this morning.... Michelin Alpins are great. Drove through an inch not plowed or salted... fresh.. I gunned it, when down a steep grade, pushed through cornners and these are very good tires. Still too early to tell, but right now, I am satisfied.

 

Love my Dunlops as well!!

Tom

 

makes good sense to me. alot of it is just personal preference imo provided you arent going 10-15 psi under the car recommended or over the limited printed on the tires themselves.

i normally run 40/44 on the 911. on my jap cars i run 38 psi... which according to the books is about 5 psi over spec.

 

This is hugely helpful feedback, thanks to everyone who chimed in.I

Just to close the loop on my question that I posed in the original post, I ended up going with the Pirelli Sottozero Series II's... But I really struggled with the choice between the Dunlops and the Pirellis. With the Pirellis, t seems that people either LOVE them or HATE them - but I really didn't hear any middle-of-road feedback! In the end, it came down to a few folks who seemed very happy using these Sottozeros in similar climates as here In Chicago. I guess I"ll see if I made the right choice when I get these mounted on my 19" Turbo rims next week....

Thanks again to all who threw out their comments on this, and I'll post my feedback on these tires after a month or two of driving on these Pirellis in the depth of our Chicago winter (which hit this week and have made my Michelin PSS's completely useless!).

 

Let us know what psi your runnin.

 

I run a 38/40 on Pirellis all winter. Ride is not to mushy and the front is actually more stable on uneven surfaces than my summer tires which tend to hunt around.

 

Sorry I missed this thread until now. For the 997 the best question to ask yourself before buying is how much snow you plan to see vs. performance in dry conditions. The Dunlop is a better tire in deep snow, but most go the Pirelli route to maintain the best dry performance that you can get in cold dry conditions. If you plan on getting into mountainous conditions I would recommend the Dunlop. Neither will let you down

Please call me if I can help.

 

I went with Nokians because they use them at the Winter driving school.
Love them all around!