The pressure on the tire is the Max load pressure, NOT the recommended normal pressure.

I've done autocross with a lot of different vehicles and measure temps across tires both autocross hot and normal driving hot. Autocrossing tends to require about 3 psi less than normal driving pressure comparing the COLD tire pressures.

 

I run the my 19" OEM N0-spec all-season Michelins at Porsche specified full load pressure settings listed on the label.

 

The pressure listed on the tire or the Porsche recommended pressure for full load?

I believe that Porsche spec'd tire pressures for the best all around performance. I do not believe they set the fronts low to increase understeer but, maybe I am the one being fooled. Porsche settings seemed to work very well with the summer tires on and work fine on the performance limited winters. Maybe when summer returns I will experiment a little...

 

Porsche has recommended pressures for full load or partial load depending on the weight of the cargo in the vehicle. They DO NOT recommend inflating to the max allowable listed on the tire itself - which is 100% wrong to do on any street car.

 

Porsche has a recommended pressure for a combination of reasons. Because our Cayennes are SUVs, performance is not the first. Like it or not, the Cayenne was designed to attract female drivers. Female drivers tend to be more safety conscious, interested in comfort over performance and less experienced drivers at the limit of the vehicle.

To satisfy the latter two, Porsche recommends a lower tire pressure. As others have noted, fully inflated the tires transmit a lot of road irregularities. As I have noted, under inflating the front tires make the car understeer. Inexperienced drivers can "deal" much more with a car sliding straight through a corner in the rain than with the back end coming around on them. I get that, and agree with that. If my wife experienced over steer, she would get out of the car, lock the doors and never go back.

Porsche's engineers are not concerned with tire life, and with the Cayenne, they are really not that concerned about cornering performance. They are concerned about the comfort and safety of their target market for the vehicle.

In the end, run whatever tire pressure you want to, but stop with the "the Gods in Zuffenhausen wrote it, so it must be obeyed" stuff. If you think running your tire pressure 22% lower than the tire manufacturer recommends, then have at it (my door panel says fronts at 39psi and tire recommended max is 50psi). But don't say it is to extend the life of the tire, because it is doing the opposite.

Have a Merry Christmas!!!

>Whatever tire pressure you decide on, please be safe over the Holiday's and throughout the winter bad road season.

 

This 🔼 +1

 

I heard it's enough to run with two wheel bolts. Porsche put five so that inexperienced people would feel safer.

 

So, you are supporting my statement? If not, please let me know what I have incorrect? That the vehicle is marketed heavily toward female drivers? That the engineers of this SUV are more concerned with safety and comfort than performance? That the engineers are not concerned with tire longevity?

Unless you can prove my statements wrong, then your addition to the conversation is without merit and your example idiotic. Thanks for playing, though. In addition to the pat you gave yourself on your back for your witty response, let me send a participation medal for your effort

 

You are wrong on many levels. Please show me the proof the Cayenne was intended for female drivers, and not the majority of 911 owners that already owned an SUV from another brand. Or that Porsche assumes Cayenne buyers are inexperienced and can't handle a performance SUV. Or - that Porsche didn't build the Cayenne to be a performance vehicle and instead focused it solely on comfort.

I guess Tire Rack knows less than you do:


Tire Tech

Tire Specs Explained: Maximum Inflation Pressure

Maximum Inflation Pressure

A tire's maximum inflation pressure is the highest "cold" inflation pressure that the tire is designed to contain. However the tire's maximum inflation pressure should only be used when called for on the vehicle's tire placard or in the vehicle's owners manual. It is also important to remember that the vehicle's recommended tire inflation pressure is always to be measured and set when the tire is "cold." Cold conditions are defined as early in the morning before the day's ambient temperature, sun's radiant heat or the heat generated while driving have caused the tire pressure to temporarily increase.

For the reasons indicated above, It is also normal to experience "hot" tire pressures that are up to 5 to 6 psi above the tire's recommended "cold" pressure during the day if the vehicle is parked in the sun or has been extensively driven. Therefore, if the vehicle's recommended "cold" inflation pressures correspond with the tire's maximum inflation pressure, it will often appear that too much tire pressure is present. However, this extra "hot" tire pressure is temporary and should NOT be bled off to return the tire pressure to within the maximum inflation pressure value branded on the tire. If the "cold" tire pressure was correctly set initially, the temporary "hot" tire pressure will have returned to the tire's maximum inflation pressure when next measured in "cold" conditions.

A tire's "maximum inflation pressure" may be different than the assigned tire pressure used to rate the tire's "maximum load." For example, while a P-metric sized standard load tire's maximum load is rated at 35 psi, many P-metric sized standard load performance and touring tires are designed to contain up to 44 psi (and are branded on their sidewalls accordingly). This additional range of inflation pressure (in this case, between 36 and 44 psi) has been provided to accommodate any unique handling, high speed and/or rolling resistance requirements determined by the tire and vehicle manufacturers. These unique tire pressures will be identified on the vehicle placard or the vehicle's owner's manual.

The tire's maximum inflation pressure is indicated in relatively small-sized print branded near the tire's bead (adjacent to the wheel) indicating the appropriate value. Because tires are global products, their maximum inflation pressure is branded on the tire in kilopascals (kPa) and pounds per square inch (psi). These values can also be found in the industry's tire load & inflation charts.



Michelin doesn't know anything about tires either:

Tires have been known to lose up to 1psi (pounds per square inch) every month, so check all tires, including your spare, once a month (or before a long trip). It’s easy. Here’s how:
1.Purchase a trusted tire pressure gauge.
2.Check your tires “cold” – before you’ve driven or at least three hours after you’ve driven.
3.Insert tire pressure gauge into the valve stem on your tire. (If you are using a digital tire gauge like the one pictured, the gauge should begin reading the air pressure immediately. Refer to your air pressure gauge owners manual for correct usage instructions. If using a "pencil" style tire gauge, the gauge will “pop” out and show a measured number. When you hear a “pssst” sound, that’s air escaping the tire. The escaping air shouldn’t affect pressure substantially, unless you hold down the air pressure gauge too long.)
4.Compare the measured psi to the psi found on the sticker inside the driver’s door of your vehicle or in owner’s manual. DO NOT compare to the psi on your tire’s sidewall.
5.If your psi is above the number, let air out until it matches. If below, add air (or have a Michelin retailer help you) until it reaches the proper number.



Goodyear should learn a thing or two from you:

Tire Air Pressure

The best solution is often the easiest. A properly inflated tire can benefit more than just the treadwear. It will help ensure that your vehicle is driving safely, extend the life of your tire and even help you with fuel-efficiency.


Why tire air pressure is important:
•Underinflation increases treadwear on the outer edges, and generates excessive heat, which can age tires faster
•Fuel economy is reduced as rolling resistance increases — soft tires make your vehicle work harder
•Too much air pressure causes the center tread to carry most of the car's weight, leading to faster deterioration and uneven wear

To find the proper air pressure for your tires, look in your vehicle's owner's manual, on the sticker on the driver's side doorjamb, or in the glove box.



Or every other internet search on the topic. Guess you know more than all of them, based on whatever you think Porsche engineers intended:


The Right Tire Pressure: Why the Maximum Isn’t the Best


At Kal Tire, we hear from a lot of drivers who ask if they should be inflating their tires according to the maximum PSI (pounds per square inch) listed on the sidewall. However, when it comes to the right tire pressure, the maximum is not the optimum.

For smooth, safe rides and long-lasting tires, it’s important to find the right tire pressure for your vehicle.

The Maximum

Somewhere on the sidewall of your tire, just below the big, bold letters of the manufacturer, for example, you might have noticed the words ‘Max. Press. 35 PSI.’ That number tells you the maximum cold pressure needed for your tire to carry its maximum load.

We mention ‘cold’ pressure because that means you’re filling up your tires at the ideal time—when they’re cold. First thing in the morning or after sitting for a few hours in the shade is best.

Usually, your tire’s maximum tire pressure is somewhere between 30 and 32 PSI.

What happens if you inflate your tires to the max PSI?
•The handling characteristics change
Since tires inflated to the max can’t give as much on the sidewall, you might see superior cornering, but it could be at the risk of your braking threshold. One quick corner and your back end could slide out.
•The life of your tire decreases. When your tires are inflated too much, the rubber rounds out at the top of the tire when you’re driving, and the center will quickly wear out. You’ll also reduce your traction and you could even cause a blowout. Check out our post on avoiding blowouts.

So, what’s the right tire pressure for your vehicle?

The Optimum

You’ll find the manufacturer’s optimum or recommended tire pressure for your car on a sticker in the door jam, or in your owner’s manual. Some models even place the stickers on the trunk lid, in the console or on the fuel door.

Recommended pressure is usually between 30 and 35 PSI. That number indicates the minimum amount of air pressure needed to support your vehicle’s maximum load-carrying capacity. Any less, and you’ll see poor fuel economy and handling as well as premature wear from too much flexing and tire overloading.

When your tires are inflated to the recommended PSI, you enjoy their optimum life and performance.

Inflating your tires

When’s the best time to check your tire pressure? A few good rules of thumb are: every time you fill up for gas, every 10 degree change in temperature, or every 30 days.

 

So you are saying that the tire pressure marked on the tire is the correct one, for every single car the tire fits on, regardless of weight and type of vehicle?

And what comes to the claim that Cayennes are marketed mainly at females, would the 911 then be targeted towards men and display the correct tire pressures on the doorcard?