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Discussion Starter #1
Do you follow the PSI recommendation on the door stickers? Porsche recommends 31 PSI front and rear for stock 18s. Seems a tad low?
 

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My car calls for 33 on 20" tires. I do use that now that I am in Florida.
I have always adjusted off the door sticker based on location (warm area or time) tires (harder side wall maybe use less air to softnen ride etc.) usage (street, track, autocross)
When I had earlier cars that called for staggered PSI I used equal pressures all around as I felt that was right for me and my driving.
 

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The sticker on the door is based on actual test results and engineering analysis. Unless you have better data you may as well stick with those values.


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It may be test results and analysis but it also for the general population over a wide variety of conditions.
I am adjust it to my specific usage, conditions and tires. If engineers were testing and analyzing for my examples they would probably be adjusting their answer to reflex my specifics not what John P Porsche needs to drive to the store in 60 degree dry weather
 

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I go by the owner's manual as the door sticker provides the recommend PSI for the 18" factory wheels. As I "upgraded" to 19" aftermarket wheels, I use the recommendations in the manual, which are 32 psi for the fronts and 36 psi for the rears.
 

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Discussion Starter #7
~32psi on 18s is a good starting point on the street. For the track I start at 24-26psi.
Yeah.. sticker recommends 31 for stock 18s but I run 32s all round.

The lower PSI for track.. is this because the tires and hence the air heats up more?

Does this apply to nitro filled tires?
 

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Nitro filled tires PSI go up a little less than plain air but they still grow a lot
You need to adjust them for your condition
For the track. You do need to consider where the specific tires like to run at; they aren't all the same.
Some tires work better at 30-31 hot but some work best at 36-37 hot
If you read the TireRack information for your specific brand and type tire they sometimes will tell what is the best range for the tire on the track
 

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the engineers are testing for the best mileage and best tire life that will work for the most people on average. people choose different tires and diff alignments. some people treat the car as a daily driver and some as a canyon/track car. I would pay attention to your usage, tire pressures, tire wear, handling, seasonal changes, etc.
 

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I run 30 front and 28 rear only because the city streets in my town suck big time and I want the tires softer. I've got just a little under 20k on the original 18s and they are starting to skip when I pull out of a tight parking space and they are getting noisy so I plan on going to GY Eagle Sport All Season and will go with the oem specs for tire pressure. I don't track the car so......
 

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I have always put in 2-3 psi more than the door sticker in every car I've ever owned, from Chevy's to Porsches. It started back in my younger days when my junk car tires did not hold air very well, so I figured I'd start out high to give more time between pumping them up. Also at that time, 60s-70s, car manufacturers tended to recommend low pressures to improve the ride, but I was always looking to make my tires last (and handle better), and a couple more pounds seemed to help. I never track my 07 Cayman; it calls for 29/36 on 17" rims and I generally run around 32/39 - the car seems very happy. :)
 

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Discussion Starter #12
Had a short spirited B-road and high speed freeway drive in Sunday on 32psi all round. Tires felt really good especially the new PS2 rears. Very good grip. Car just felt a tad floaty on straights past 120mph... getting a pair of Verus front dive planes to hopefully help increase front downforce and reduce the floatiness at speed. Am getting Cayman R springs on as I type so hopefully the 20 mm lower stance will also help in that regard.
 

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The springs might be enough,(will remove float and lower nose) - w/o dive planes
Where did you find a 120 mph area ?
 

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I've always ran 33 PSI all around with the 20's. In the past I've had P Zeros and Pilot Super Sports and they've felt good in this configuration. This time around I went with Extreme Contact Sports and I can tell the side walls are a bit softer. I may pump them a bit higher to see how it feels. It's worth noting, though, that with X73 suspension, this is the most comfortable my car has ever felt.
 

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I prefer the feel of higher pressure. Also it will eat less sidewall on the fronts. So I run 38/32 on stock 19s. Suggested pressures may be well for average, on stock tires, but if when start learning more about car handling, you'll quickly understand that german engineers don't always know better for you:)
 

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Discussion Starter #16
The springs might be enough,(will remove float and lower nose) - w/o dive planes
Where did you find a 120 mph area ?
Up north and literally into a neighboring country. I did hit higher speeds at times and really wasn't comfortable with the lighter floatier front end at speed. Its an increasing age and shrinking cojones issue...
 

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Clearly reading the many recent posts people are adjusting PSI to their cars, conditions, equipment & tires; not just using what's on the door.
 

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After wearing out a set of rears far too fast in the middle I've adjusted to "comfort" settings most of the year. Handling not affected in normal road use.
 

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I've always ran 33 PSI all around with the 20's. In the past I've had P Zeros and Pilot Super Sports and they've felt good in this configuration. This time around I went with Extreme Contact Sports and I can tell the side walls are a bit softer. I may pump them a bit higher to see how it feels. It's worth noting, though, that with X73 suspension, this is the most comfortable my car has ever felt.
Agree - I run door sticker (33) all around on my 2015 CS. With the new PS4s I feel they have a harder sidewall than the F1 Goodyears that were on it. But I want even wear since we cannot rotate due to size, so I will leave it as Porsche recommends. They are certainly awesome as-is, unless I see a real reason to change them.
 
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