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Old 07-16-2009, 09:32 AM   #1
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Pirelli P Zero Rossos Tire Pressure

Hi kids, haven't been around here for a while but thought I'd bounce this off you.

I have Pirelli P Zeros all around (225/40 front, 265/35 rear). I noticed a lot of wear on the rears and took the car to America's Tire where I bought them to see if the wear was normal. I was told the tires were wearing a lot in the center of the tread but not very much elsewhere, indicating the tires were over-inflated. The thing is, I kept the pressure at exactly the pressure recommended by Porsche.

I've deflated the tires a few pounds in hopes the tires will last longer. And the car seems to corner a bit better as well.

So who's right about the tire pressure, Porsche or America's Tire?

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Old 07-16-2009, 07:06 PM   #2
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How accurate is your gauge?


Did you measure hot or cold?
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Old 07-16-2009, 08:48 PM   #3
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Slogan are you running 29 psi up front and 36 in the back? I believe that is what Porsche recammends but I would play around with the tire pressure and go by look and feel since every tire has different sidewall stiffness, wear properties, ect. I run PS2's currently and run 33 psi up front and 36 in the back for both street use and autocross and have very even wear accross the tire especially up front. The inside of the rears usually have slightly more wear because of the negative camber which is how it's set from the factory so that is normal. Usually the lower the pressure the better the ride and traction, but you don't want to go so low as to roll the tire over excessively on the sidewall when cornering. I would play around with pressure some and try to find a good balance. You can run chalk accross the tire and see how much the tire is rolling over and where it is wearing. Make sure you check the pressure when cold so your adjustments are consistent.
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Old 07-16-2009, 11:16 PM   #4
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P Zero Rosso's here. Run 29PSI front/36PSI Rears.

20+k mi. and I'm still waay below the wear indicators Fr/Rr - expect 25-30k mi. before needing a swap - Street/Auto-X.

If your's are different, suggest an alignment check.

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Old 07-17-2009, 09:02 AM   #5
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Yes, i have been running 29/36 cold, and experiencing wear the wear mentioned. Haven't had an alignment in a while, so maybe I'm due.

Thanks guys.
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Old 07-17-2009, 03:25 PM   #6
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My tires wear same as you describe.
Pressure and alignment are set to factory spec.
Maybe it is a characteristic of the Rosso's?
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Old 07-18-2009, 07:33 AM   #7
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My tires (Pirelli Rosso) also wear like that. I also thought too much pressure and started to drop the pressure a little at a time until I was under 30psi. I emailed the manufacturer which was NO help (thank you very much pirelli), all they said was "follow the manual.". 10K miles to wear out the rear and the front is still good, it seems about 2 rears to one set front tires wear. Center wears but sides are still good. Most of the driving around here is windy roads.
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Old 07-18-2009, 12:31 PM   #8
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The OEM spec negative camber set-up on the rear assures that the rears will wear faster than the fronts. These are also the drive wheels and that also affects wear.

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Old 07-18-2009, 01:45 PM   #9
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Photos I've seen online are consistent both with your description and the way my Pirellis wore.

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