Many thanks for your reply. It will be very interesting how hot these can go, as I live in Queensland and it do gets very hot in summer especially where the race track is.

If you search my nick you would find me very active on another forum with a different make and what I am doing (and what I have done) to my car. I do find this forum's posts very helpful and have been lurking for a number of years, but thought I should joined and contribute as a member. I am also seriously looking into the 991 once it is out here .

I just started to look into my suspension setup and have been speaking to two gurus in suspension here down under. Interestingly, they start their suspension setup from the intended tyre use, and specifically from their effective spring rates.

So, to answer your scepticism the fact I am about to change my suspension setup gives me the ability to optimise it to the intended tyre use .

I am 95% sure I am going with Trofeo R at this stage as I need a new set of tyres fairly soon. It will be very interesting to see how MPSC2 will compare once it is out, but I don't think it will have sizes in my application for a while. If it comes to the point where I decide to go with a different tyre, springs are fairly cheap anyway well less than tyres!.

 

The TrofeoR can handle a bit more spring rate than the circa 230/600# in OEM GT3s. They're relatively soft to begin with (vs. the OEM MPSCs that these cars are designed around). I might not go beyond a 300/800 but that's purely personal choice. 997GT3North has done a whole bunch of work on this topic--you can search and find quite a few posts under his name. Good luck with your project!

 

Thanks!

 

I've tried 2 sets of Trofeo (non R) on a 997 gt3... It had to do and redo the alignment a couple of times to find the best set-up. -3.3F and -2.7R, finally it stopped to wear on the outside and I could finally enjoy the fully grip! It seems that those Trofeo are really close to the grip of a R6 and they last when you got the good camber and pressure. Am I the only one that feel better with pressure around 34psi? I was talking with the guys at Pirelli and they told me that a lot of Porsche guys are running the Trofeo at higher pressure. But the key with those tires are really camber, if you don't have enough, you'll ruin them.

 

My experience is similar. I run a modified C4S and have been upping the negative camber to eliminate the outside wear. I'm current at -2.6 front and -2.9 rear (different from GT3 I believe due to AWD) and have even wear. The local Pirelli rep says 36 psi hot as minimum and I have excellent grip at that pressure. I ran lower (30-32 hot) on my second set and experienced sidewall splitting on the very outside layer of rubber, nothing deep. Pirelli replaced for free and said I was running pressures too low. Rep also said they find -2.8 negative camber on front is ideal.

 

That seems to be a contradiction from the Pirelli website:

The right pressure for racetrack driving

P Zero™ Trofeo R does not usually require higher pressures for racetrack use. It is designed for use at a pressure of approximately 2 bar, to be adjusted according to the type of car.

The figures indicated refer to the “operating pressure”: the pressure of the tyre when it is fully warmed up to working temperature. For accurate calibration, it is essential to consider that the difference in temperature between a “cold” tyre and a “hot” one is quite significant, normally 0.5 bar.


How many are seeing issues with 2 bar hot pressures? How many are having success with higher pressures?

 

I run them 26 front and 28 rear, Fiat. Even temperatures.

I don't follow manufacturer recommendations, as every car/driver/track/weather is different. Whatever the pyro tells me, and the inside/outside edges tell me, is what works.

Super sticky tire, the fastest treaded tire I have used on dry conditions. Pricey.

 

I hear what you're saying about this contradicting their literature and I raised that issue. The response referred to the point about adjusting to the type of car and I was told the Porsche required a higher psi. It seemed to make sense to me in light of the sidewall cracking I've experienced. I've seen it on two sets of the non-R Trofeos so I've started running 36 psi hot. BTW, I routinely see a 10 psi increase from cold to hot. My take is that it's a tire quite sensitive to pressure, camber and type of car (make & AWD vs RWD). I do really like the tire for the track and recommend people try it.

Has anyone else seen this cracking/splitting?

 

Postes pics after 1 day, 5 sessions of 45 minutes at Spa
Camber of -2.40 rear -1.40 front on 997.1 Gt3
Lap times 2.51 best and about 2.54 continu which is pretty good
Temp was around 20' C
Ran them at 2.0 bar (30 psi) all day and they were great, awesome really. Take no time at all to heat up and stay at same level of grip all through the session.

Would definetly advice them over mpsc.

Pics in post below

 

It's good to know because there is nothing that pisses me off more than wrecking a fresh set of tires... I have been thinking about trying these tires and each post of happy people helps move me in that direction.

 

Here are same pics but after three days @ spa

Same alignment - same lap times - some instruction time and one very hot day on which tyres became greasy no matter the pressure, I was at 2 bar hot ...so I figured I couldn't really go lower or could I ?

Greatest tyre I have driven, just not ideal when really hot.

What do you guys think and how many days left on the rears ?
Each I day represents 4 or 5 40 to 50 minutes sessions

Doing a double trackday and have one more lined up right after it ...
Will they hold it for one, two or three more days???










Fronts :

 

I have (2) used fronts 235/35/19 if you need them.

$200 shipped.

 

You have plenty of life. Here's what my FR looks like.

 

I'm running my 2nd set at 3.2* camber in frt and 2.5 rear and they wear well. My first set wore out really fast at ~ 2.2 frt /rear.

I don't run hot at 2 bar, more like 2.3 bar...have to start very low due to heat/pressure build up.

 

Agreed JP!