correct tire pressure for Pirelli PZero's?

[homewood]

V10 Spyder with stock Pirelli PZero's which I got from dealer had pressure set at 36 psi for both front and rear tires. Both driver's manual and table on the driver's side door pillar recommend 45 psi for front and 41 psi for rear at normal and max loads. Should I be concerned about the discrepancy ? What psi have you run your tires at?

[rmicroys]

Ya, gotta love techs. There are so many techs that just think "36 psi is what all cars should run"... well buddy. Nope. Run what the sticker on the car says.

As an aside, I have load E tires on my truck, I keep getting the truck back with 36psi in the tires. It's supposed to have 55psi or more. I'm not sure what the techs at Ford think when they service my truck but I always have to remind the service advisor what I want my tire pressures set to so they do it correctly. Sigh.

[KfabR8]

14.7 psi, or ambient air pressure, meaning they don't have rims in them...

Sorry, I just had to!

[harrison]

In general there will be a difference from ambient (COLD-tires) to HOT tires of 6-10 psi. Generally 10 deg. F is equal to 1 psi . So, a spirited canyon run will put a 40 psi cold, up to 50 psi. DANGERUS !!! Tires warm up really well on dirt too. So, tire pressure is a FINE tuning adjustment.Taking temps after a cool down lap is useless. 30, 35, or 40 - HOT is a good starting point. YES MY DOOR STICKER SAYS 39 FRONT 36 REAR COLD---Perfect temps FOR THE STOCK PIRELLIS HOT on the track. I USE THESE FIGURES AS MY HOT PSI-For Hoosier R6 slicks/Toyo R888s (on a track). You will find yourself using your compressor quite a bit when trying to keep things proper. You might need a glove for heat protection when releasing that hot air/nitrogen pressure. Bleeder type gauge of course. I use AIR still. Sumptins up about that sticker? Next, I need to pay waay more attention to the tires surface temps. I have a lazer tool but wonder if the probe type might be better.Getting this stuff close to good makes for a safe aggressive outing.

[mark25]

I just put 39 in both my front and rear tires is this wrong? Im sure it says 39 on the passenger door will confirm when I get my car back!

[homewood]

So, a spirited canyon run will put a 40 psi cold, up to 50 psi. DANGERUS !!!...YES MY DOOR STICKER SAYS 39 FRONT 36 REAR COLD---Perfect temps FOR THE STOCK PIRELLIS HOT on the track. I USE THESE FIGURES AS MY HOT PSI...Sumptins up about that sticker?

Harrrison: Not doubting you... but now quite confused. I know there is a difference with tires on V8 vs V10. I had reset tires to recommended cold tire pressure at normal load which on the 2011 Spyder V10 is stated to be 45 psi front and 41 psi rear (both in the manual and on the door jamb). Again tires are the stock Pirelli Pzeros. Can others weigh in on this?? Have not tracked the car and for now use it for daily driving and occassional long weekend drives.

[rmicroys]

The sticker pressures are fine for normal driving.

As Harrison said, for the track 36 hot, all four tires. I ran the OEM pressures by mistake for one lapping day and ripped the center right out of my front tires. blistered the tread blocks and they just started to rip out of the tire. Thankfully, SpeedMerchants, the guys that runs the hotrod shop at the track at Calabogie stocks all sorts of tires that fit the R8 at the track. They gave me two new Michelin Sport N2s and I was able to go home at the end of the day.

[desperado]

I can confirm that my 2009 V8 Coupe specifies 39 psi Front and 36 psi Rear, equipped with PZeros. This is the first I've heard about R8's having a higher tire pressure specified.

[homewood]

Can other 2011 V10 Spyder owners equipped with stock PZeros weigh in and confirm that specs call for 45 psi front and 41 psi rear for normal daily driving ??

[KfabR8]

Those specs (41/45) are for a fully loaded vehicle; think GVW, not running weight.

You want to stick with a 34-36 f, 38-40 r psi range. Any more and you'll start wearing the center of the tire sooner, any less and you start wearing the shoulders.

The weight of the cars is more what sets the pressure, as the idea is to get as much contact patch versus rolling resistance. The weight variance among V10/V8, Coupe/Spyder is minimal, so a blanket statement of 39r/36f psi is pretty much spot on.

If you drive your car aggressively, you'll want to play with the pressures a bit to balance the road holding aspects of each end. If you're out and about, just enjoying your wonderful ride, 39r/36f psi is once again the perfect place work with.

Notice - even the comments that mention track usage, the focused pressure is generally right around, you guessed it, 36 psi (hot). It's what works for the car.