Michelin PSSs pressures...
11-20-2011, 11:15 PM
#46
Nordschleife Master
Thanks Gary! This last post further confirms and clarifies the absolute temp ref method for winter tires.
I take the opportunity to remind the forum that summer tires do not work and are outright dangerous below 40F/4C.
I take the opportunity to remind the forum that summer tires do not work and are outright dangerous below 40F/4C.
12-12-2011, 12:27 PM
#47
This thread is dead and should stay buried but I'm reviving it - for a reason.
The 997.2 is my first car that reports live/hot PSI numbers (I love that feature by the way). My last porsche was an 06. Now that I've had the 997 for two months and we finally hit some cold temperatures, I made some observations. None of this is for the track, all for street and for temperature compensation. I did see that garage: 33/39, left out in the cold 31/37 (so too low according to my old view), both warmed up to a good 36/42 with easy driving.
Previously I did not understand the mechanism of how/why a tire warmed up. Indeed it is less dependent on exterior temperature. It's not completely independent, but it's much closer to Gary's answer than to Fred/Alex/mine.
The conclusion: set them to 33/39 in a cool (53F) garage. Don't worry about exterior temperature so much. Don't add extra if it's 20F outside. Enjoy driving the car.
Incidentally 33/39 @53F is about equivalent to 34/40 @ 68F/20C, the book recommendation.
As to 37/44 for cold/full load, I am baffled. I do know that the car starts riding like crap at hot 39/45 and above, so this recommendation just seems to be liability driven. My wild guess.
The 997.2 is my first car that reports live/hot PSI numbers (I love that feature by the way). My last porsche was an 06. Now that I've had the 997 for two months and we finally hit some cold temperatures, I made some observations. None of this is for the track, all for street and for temperature compensation. I did see that garage: 33/39, left out in the cold 31/37 (so too low according to my old view), both warmed up to a good 36/42 with easy driving.
Previously I did not understand the mechanism of how/why a tire warmed up. Indeed it is less dependent on exterior temperature. It's not completely independent, but it's much closer to Gary's answer than to Fred/Alex/mine.
The conclusion: set them to 33/39 in a cool (53F) garage. Don't worry about exterior temperature so much. Don't add extra if it's 20F outside. Enjoy driving the car.
Incidentally 33/39 @53F is about equivalent to 34/40 @ 68F/20C, the book recommendation.
As to 37/44 for cold/full load, I am baffled. I do know that the car starts riding like crap at hot 39/45 and above, so this recommendation just seems to be liability driven. My wild guess.
05-27-2012, 10:31 PM
#48
Intermediate
Join Date: Oct 2004
Location: Melbourne, Australia
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GARY THNX FOR YOUR GREAT POSTS
I did quite a biit of research getting info for my project of turning my 997S.1 -20mm sport chassis 2005 into a 991 comfort and handling unit.
Well i know i don't have all that the 991 has to offer but just to get the car feeling as good as it does now with some of your info and tips has been fantastic, so much appreciated mate and I hope one day when I'm back in the states I can meet you and buy you a soda or 3 :-)
kind regards
SteveS (Aussie)
Well i know i don't have all that the 991 has to offer but just to get the car feeling as good as it does now with some of your info and tips has been fantastic, so much appreciated mate and I hope one day when I'm back in the states I can meet you and buy you a soda or 3 :-)
kind regards
SteveS (Aussie)
