Mister Quickie

My rear tires are 285/30 ZR18
My front tires are 225/40 ZR18

The "max psi 51 ... never inflate beyond 40 psi to seat beads" is written on all four tires (both front and back)

currently the pressure in both rear tires is ~35
currently the pressure in both front tires is ~30

based on the tire chart inside the gas cap lid (below) I plan on inflating the rear tires to 44 and the front tires to 36

recommendation to proceed?

fpb111

Why would Porsche put recommended tire pressures on the car?
30-35 is too low.

roadsession

That message of never inflate beyond 40PSI to seat beads is a message for TIRE INSTALLERS when installed the tire onto the wheel. That has nothing to do with air pressure of a running car....
The tire pressure recommendations on your car is what you should set it to.

Just curious - but is this your first vehicle you've owned/operated/maintained?

Byprodriver

Also keep in mind the 51 psi max is for the tire not the car as the tire can be fitted to many vehicles heavier than the 996

Sneaky Pete

Rear should be 44 and front should 36.

vange_c4s

^^x2

Zookie

Actully New TSB:-

43 Rear and 36 Front @ Full Load.

Half Load is 32F and 36R

Mister Quickie

I did rear 44 and front 36 and it feels better

Thanks guys

Zookie

try 43R.

ivangene

actually......

drive them and check the temp HOT....what you dont want to see is the tire pressure increase past 51 EVER...now there is also a "sweet spot" were the tires perform best and that might be about 46....so depending on how you drive and the road temp you want it to peek at about 46....if its high, bleed some off...if low...add some

then let them cool and see where the "start point" is

the more you corner and the harder you drive the more heat and thus the higher the pressure will be.....car weight and road condition, road temp, ect all play factors in this. I found once I got my tires to ALL run at 46 (front and rear HOT) that the car really came alive in the turns


LET THE FLAMES BEGIN

Torontoworker

Tire pressure is decided by operating temp's, weight of car and use. There is no standard pressure for ALL intended uses. The old 36/44 standard worked more for Porsche's liability lawyers then the end user. All it did was create more under steer for a rear engine car design with inherent over steer characteristics as the full fuel load up front decreases. Porsche has to worry about the worst type of end users driving conditions where they are very fast for hours on highways in hot temperatures with passengers and full luggage. 35psi rear would be moderately under inflated in this scenario and considered grossly under inflated for track days.

jadatis

The car-makers use a formula to calculate tire-pressure.
I once got hold of the one the European tire-and car-makers use since decades, and the Americans since 2006.
After 2000 they chanched the loads to fill in but the formula is still used .
Tire pressure advice is all about load and speed , and a bit about camber-angle( alignment).
Use on my public map of skydrive that belongs to my hotmail-adress with same username as here 9( combine it yourself).
7th map about re-calculating tyre-pressure. If you want to play with the temperature to see what it does to the pressure spreadsheet 1 from the bottom "pressurecalculation with temp"
Click on spreadsheet at the end on I in a cirlce , then at the right barr download.
Open in Excell or compatible to use it.
And if you cant work it out , ask me here.
https://skydrive.live.com/?cid=a526e...E092E6DC%21128

Greatings fromm Holland
Peter