sailorlite

Had a set of the new Michelin Pilot Sport 4S installed yesterday at the local America's Tire. I asked them to set the pressures at 34/40 per the stickers and owner's manual. They declined that request saying that the original Porsche suggestions for the 997 are no longer optimal due to changes in tire manufacturing. This tire dealer is generally quite careful with their recommendations but I'm not sure they got this one right. Do the newest 911's recommend the higher pressures?

Wayne Smith

My tire dealer is very good. He interviewed me to determine alignment and pressure. He recommended similar pressures.

FWIW ... I'm getting about 27K miles on my rears and near 40K on my fronts.

But if I forget to lower the pressures before a spirited drive I find myself spending a lot of time in the air and sliding through turns!!!

golfnutintib

my 997.2 also said 37 44 on stock 19s - that is way too high imo

these figures are often tweaked for mpg ratings

i run 33 37 cold for regular street use

nice compromise for handling noise rim protection fuel economy

Hella-Buggin'

I run 32/36 cold for street use. I tend to incorporate twisty roads in often enough that that's a decent compromise. Keep in mind that some manufacturer pressure suggestions are based on fuel economy and tire life.
I care about grip, but I get about 15 out of my rears and 30 from the fronts. I'm running AD08R's and they're not happy over 40PSI in the rear.

j beede

What a coincidence. I get 27/40 MPG city/hwy with my 997 C2

...of course that's when driving on the planet where you get 27,000 miles on your rears

j beede

36 front and 38 rear cold. These pressures rise to 42/44 after ~15 miles at interstate speed. 20" P-Zeros.

Wayne Smith

I checked my records ... every 25K on the rears. But I try to replace them a bit early. 35K on the fronts, but again while they have some tread left.

I'm lucky to get 30 mpg highway, and spirited can be low teens. You'll need to provide evidence of your 27/40!!!!!

mcfisticuffs

What are your alignment settings? The Michelin Pilot Sports I just took off lasted about 10k kilometers rear and 20k front. Less than half of your mileage. Or do you drive like a grandma??

Edit: You posted alignment settings as I was posting this.

My amazement has yet to cease, tho.

What was the outcome of your interview? Why did you get those particular settings?

TheBruce

I'm at 33/40 cold on PS4s. Anything above that and I found the ride way too harsh. I actually blame my broken pressure plate on running 44psi in the rear.

Wayne Smith

25K anticipated miles a year. 80 to 90% freeway commute. 10 to 20% spirited. Grew up on dirt, snow, and ice. Willing to live with less rear toe for longer tire life. This was a personal decision with handling compromises that may not be right for everyone.

I won't speak to how I drive, but definitely DO NOT forget to lower the pressure before going out to drive like grandma 8)

dasams

LOL Another 'my thingy is bigger than your's post. Carry on...

evo9

FWIW - I'm a new (< 1yr) owner of a 2010 C2S. Car had new rear P-Zeros on it when I obtained it. My Indie advised me to run tire pressures as recommended on placard in drivers door jamb (37/44), said tire would last longer and that lower pressures contributed to inside tire wear. Seemed extremely high to me based on pressures I've previously used on non P-cars but, I said what the h3ll and decided to try it.

Well, I have 10K mikes on tires and rears look like new. No noticeable inside tire wear vs outside of tire. Tread wear is even across width of tire. My instinct (which was wrong) had anticipated that center of tire tread would wear more outside using 44psi. I guess the rear weight bias of car, really means that rear tire pressure >40psi is not only OK, but the right way to go per my Indie and Porsche.

BTW - My driving style is highly spirited. Many stints up to 110mph, many visits to redline (once oil up to operating temp. or course), and attacking on-ramps like a beast (weather and traffic conditions permitting). I.e.. I drive it like I stole it when the wif's not with me, LOL

pEace oUT

david

Hmmmmm...I'll speak to how you drive: "grandma" is not a word that ever comes to mind when I see that dumbass grin on your face in my side-view mirror or I see you airborne in front of me on our special roads of the NorCal coast (with much to much air in your tires but I digress) or while traveling on the roads traversing the Sierra or the Cascades, or east of those ranges (see below).

PS: 33/37 cold for me is the ideal all-around tire pressure for the MPS4S.

Doug H

Wayne Smith

Beautiful shot with that background. Reminds me for those who may not realize it ... you can use the throttle while airborne over whoopdies to lower the backend and smooth out those landings. Kind of like riding a motorcycle 8)

Likewise drop off the throttle to lower the front if you need to adjust the other way.

These really are amazing cars!!!

And I agree with David about tire pressures when having fun. Another very technical friend states that no matter what the fronts should be 5 psi less than the rears.