North Shore 911

With Winter now well and truly upon us here in Chicagoland (it was -12 degrees at the Bears-Packers game on Sunday ), I'm wondering what tire pressures you guys are running on all-season tires during the winter months. I'm running 20" Pirelli All Seasons, partial load. The sticker on my door jamb shows 38/47 (I think), but that just doesn't seem right. I'm more inclined to go with something closer to 35/39 ....

So what are you guys running this winter?

Dilberto

I run Continental ExtremeContact DWS06 275.40ZR20 106Y. They have super-soft sidewalls. Max is 51psi. I air them up to 45/49psi, for best wear and traction.

prosled8

I am running what the TPMS tells me too so I do not have to look at the warning lights. I have it set for winter partial load on 19s. I think it is 38/50 but I would have to look to be sure. I suspect it is related to the heavy rear torque bias and helps preserve tires to some extent.

7 Summits

You should run factory recommended pressures. I run a couple PSI higher to increase tire life and gas mileage on long trips on the highway, otherwise keep it at recommended pressure. Only time you want to drop your pressures are if you are driving on soft sand, or actually get stuck in the snow and have exercised every other option (tip-you can use your floor mats under your tires for better traction).

CarGuyNVA

2011 CTT with 19" OEM N0-spec all-season Michelins. Factory inflation specs call for 34/39 front/rear. Currently running at 36/41, just slightly higher to account for colder snaps. I see no need to run anything different from the OEM inflation specs unless perhaps you're running some unique non-stock wheel/tire combo?

Also remember that there's 2 different OEM inflation specs for each factory wheel/tire combo, one for partially loaded and the other for fully loaded. The one I reference above that I'm running is the partially loaded spec.

ScootCherHienie

The only time you should use pressures different than the factory pressures on the door frame sticker are "special cases". I set pressures 2 psi higher than the door frame sticker and refill tires when pressures drop more than 3 psi below the sticker pressures. "Special cases" would be non-daily-driving conditions... off-road on softer/looser surfaces, drag racing (depending on whether your Cayenne can spin the tires with stock pressures or not), and autocross.

Avec

I noticed that the TPMS display shows tire pressures much lower than the on-tire recommendation with no ability to change. That is a problem when the on-tire pressure is quite a bit higher. Not to mention that the display recommends front tires to have lower pressure than rears. For a street car that likes to understeer anyway, that is pretty stupid.

You really don't need to adjust pressure based on air temp, because on the road the tires will basically reach normal temperature regardless. Use the recommendation on the tire. Mine recommend 50. I run between 48 and 50 in front and 44-45 in back.

beqok

Avec I think you should read the following link:

http://www.tirerack.com/tires/tirete....jsp?techid=73

I agree you don't need to CHANGE tire pressure due to change in air temperature. BUT you do need to add air during the winter to JUST maintain the SAME pressure. In Indiana you probably lose 5 PSI summer to winter if you don't.

By the way the pressures shown "on-the-tire" or on the sidewall of the tire are do-not-exceed pressures. They are NOT recommended pressures for the vehicle they are installed on. Porsche does a lot research on tires and air pressure; I would have to have some pretty strong reasons to vary from those recommendations (in the manual/on the door jamb) and I don't believe they include using higher pressures in front than in back!

Tom M

Tire pressures are normally stated as "cold" pressures and that's when they should be set. Thus, when it gets significantly colder, like it is now in Indiana, the starting pressure should be adjusted accordingly as the internal tire pressure will drop in the cold weather. I normally target what the median temperature range for the day/week will be, set it with an accurate gauge and run with that. Not surprisingly, the TPMS reports slightly different pressures.

Once it starts to warm up again I'll let some of the air out but the starting pressure will still be what I normally run - 34F/39R on my all season Pirelli Scorion Verde.

The warden

beqok has it right. Never use the pressures stated on the tires, always use the vehicle manufacturer recommendations. Manufacturer engineers have determined what pressures are best for their particular vehicle. I run 36f/40r on both summers and winters. That is the recommended pressure for partial load and not running high speed. If I have 3-4 people in the car and intend on running at 80 mph on the highway, then I run the max pressures indicated by Porsche.

Avec

I agree with the cold pressure change in cold weather, but normal operating temps summer and winter will be about the same. However, the OP questioned what PSI and said he was going to lower his pressure (for snow?). My point is that summer and winter normal operating PSI should be the same summer or winter

I take the recommendations from the tire manufacturer over the car company every - single - time. Also, Porsche's recommendation of running lower pressure up front makes zero sense, unless you like not turning.

If you consider the Cayenne a load carrying vehicle, the only time rear pressure should equal front is when fully loaded, otherwise lower pressure, even if just for comfort. Max inflated rear tires on an empty load carrying vehicle make for a bit of a harsh ride.

Also, the recommendation of lower front pressure is due to people being able to stand on the brake if they are understeering, but freaking out if oversteering. Their recommended PSI is for people like that. Porsche's considerable research in the area is to mitigate liability not increase performance. If you are a "freaking out" kind of driver, then please use their recommended pressure, front to back. However, I can tell you that the Cayenne becomes much more neutral with near tire-recommended-max PSI in front and lower in rear.

vchris1987

So what do you recommend for summer tyres staggered setup on 20's. Even in comfort mode and Normal ride height I find the ride a bit harsh. Although, I have a Gemballa Air-suspension module installed and I am a bit lower in normal - level than stock!

beqok

[/QUOTE]I take the recommendations from the tire manufacturer over the car company every - single - time. Also, Porsche's recommendation of running lower pressure up front makes zero sense, unless you like not turning.

If you consider the Cayenne a load carrying vehicle, the only time rear pressure should equal front is when fully loaded, otherwise lower pressure, even if just for comfort. Max inflated rear tires on an empty load carrying vehicle make for a bit of a harsh ride.

Also, the recommendation of lower front pressure is due to people being able to stand on the brake if they are understeering, but freaking out if oversteering. Their recommended PSI is for people like that. Porsche's considerable research in the area is to mitigate liability not increase performance. If you are a "freaking out" kind of driver, then please use their recommended pressure, front to back. However, I can tell you that the Cayenne becomes much more neutral with near tire-recommended-max PSI in front and lower in rear.[/QUOTE]

As I said previously unless I have some "pretty strong reasons" I use the recommended pressures.You seem to have those strong reasons. You are looking for MAX performance not comfort or tire longevity. I don't race mine either on the street or elsewhere, so comfort, tire longevity, and occasional fast driving is what I want. If I'm going long distance across several states at freeway speeds then I have "strong reasons" and bump the PSI up a few pounds.

leftlane

Running your tire pressures at the max allowable listed on the actual tire is not correct at all. Why would you not run at the recommended PSI per the manufacturer instead of what you believe to be better? As the tire warms up your tire pressure will be way over the max anyway. Overinflating is going to lead to some bad wear patterns in the middle of your tread.

I don't get why you wouldn't believe what Porsche, in concert with the tire companies, recommends for their vehicles. Makes no sense. Don't get your impression of drivers who freak out either - based on your own scientific study, I assume?

My TPMS tends to run several pounds higher than the pressure measured at the valve - anyone else seeing this too?

Tom M

If you are really in search of an optimal pressure then you need to figure out what pressure puts the full contact patch evenly on the ground at operating temperatures the same way folks who track their cars do. It's something that can easily be done using an infrared thermometer these days by just measuring the temps in several spots across the tread after getting the tires to operating temp and driving how you normally drive. This will tell you pretty quickly if you are over/under inflated.