Deanski

I do what the manual says as well for partial load 33/39 PSI.

Hey, they built the car, and I think they have a damn good idea on correct tire pressure for which load.

However, there is always room for tweeking this as tires are different in type, weight etc.

Then, there's Nitrogen instead of good old free air.

So far, my P-Zeros have lasted 16K miles. Not bad at all! Due to tire prices, I may be going to the Bridgestones.

Deanski

pbarch1

Would an increase in the front pressure help prevent the push I get when driving hard on the twisties? I know Porsche sets the car up from the factory this way to keep Joe average driver (me) from getting into trouble but I would sure like a more balanced feeling. What would you guys recommend for a more aggresive driving style?

Jim Chambers

I think the opposite is required. I was taught "if the front is loose (your situation), tighten the rear" and vice versa. More pressure in the rear would "tighten" it (or maybe less in front).

cole328

I heard same I am using 35F 42R seems great so far

chuckla

I run 37F 44R and am happy. Remember, DC has third world roads!

cole328

yeah that 7 lb differential seems to work nicely

irish guitar

Deanski, you've gotten 16K on the P-Zeros? I'm just over 10K on mine and I suspect that the rear isn't as grippy as it once was. At what mileage did you notice any change in grip? Have you seen any noticable wear?

Without putting the car on a hoist, I can't see any significant wear on my rears as yet.

I also run 33/39.

heinrich

Interesting thing happened ... I have been running 18's on my 928S4 which is 50/50 weight distribution, weighs 3378lbs with me in it. Pressures all round on 18's of 32PSI work really well. Wear is even; grip is perfect wet and dry.

I recently started using another set of twists with brand new Pirellis, 19". Front 235/35/19; rear 265/30/19. At 32 all round the car was very tailhappy. Tyres looked visibly underinflated, and temperatures were hotter outside edges than centres. I inflated to 40PSI all round, and the car's handling, steering, and tyre temps all improved immensely.

I realise the 928 is a very different animal. I'm just saying, if you run nonstandard wheels/tyres, you may want to look really carefully at pressures. Going from 18 to 19 changed everything for me.

Le Chef

On 19" and summer tires I run 33/39. On 18" and winter tires I run 36/44. Essentially what the manual says you should run.

Deanski

Yep, 16+K on the whole set! Ran the 33/39 pressure since it's mostly just me.

Yes, as they wore down, they became more noisy and didn't seem to have great grip. Worse in wet weather as they treads were getting down, but no cords or uneven wear. I also got more road noise from the tires seeming to flat-spot faster and longer in recovery from the flat-spot.

I now went to Bridgestone RE050A's. Very nice tires! I went up to 305's in the rear, which fills out the rear wheel well very nicely. I hope I get long mileage out of these as most driving now is highway and some backroad work.

Damn hard to get the RE050A's... I had the dealer order them via Tire Rack.

Regards,
Deanski

Sands

Like many, I am using 33 front and 39 rear on my Pirelli P Zero's. I recently put Michelin Pilot Sport PS2's on my Mercedes and was astounded at how good they are. When the time comes, I will be switching the Pirelli's for the Pilot Sports on the C2S.

unclejosh

I am quite pleased with the tires for both street commute and track.

Great wear and very good grip. Predictable.

I cannot overstate the need to keep the tire pressures up to 33/39 at 70 F.

Small potholes and other road debris can cause a sidewall bubble or hernia wherein the cord delaminates or is breached after impact and only rubber is left to hold the pressure, thus the hernia.

This is an unfortunate common occurrence for 19 " wheels and low profile tires.

I recently had to replace a set of tires due to a sidewall bubble on my R front which might have been caused weeks earlier by hitting a small rock or a pothole. Kinda frustrating since the tires were still working well and perhaps 1/2 worn to the indicators at 10,000 miles. Since my car is 4wd, I ended up replacing all 4 tires due to potential large depth wear imbalance if I had new fronts and kept the 1/2 worn rears. As per Porsche, the 4wd viscous coupling mechanism can be damaged if wear or tires are significantly dissimilar. I took the precaution........