The car is finally back to normal. Final tally:


2 new front tires
1front wheel dented- repaired
1 rear tire spun - road force balanced from 38 lbs to 20 lbs
1 complete alignment needed
I should check my rotors and brake pads....have not done that yet.








I also bought a set of track wheels/tires for my track days.

 

shumi - I think you sent Pirelli the worn tires - did they ever get back to you with a reason or explanation as to what happened to the tires?

 

Shumi,

If your R-comps are brand new, you should heat cycle them one time before you take them to the track for max longevity. A heat cycle is defined at going from cold to full temp, then full cool down. Let us know how you like them at the track - I predict it will be on the order of "OMG! I CAN'T BELIEVE THE GRIP!"

 

Shumi,
I've done quite a bit of track work with my 997.1 and so while our cars are not identical, my guess is they have many similar characteristics - gross weight, weight distribution, etc. Just imho, your tires are Waaay over inflated. After driving 50 miles to the track, I start my streets or r-comps at 26 F and 29 R and after the first session bleed them down to 32 F Hot and 35 R Hot +/- 1 lb.. This bleeding process may have to be repeated if the ambient and/or track temps rise through out the day. You can expect all of your tire (idiot) warning lights to light up but just ignore them. At the end of the day, inflate all your tires to 45-50 lbs and drive home. The lights will eventually go out and then the next day after the tires have cooled, reset the pressures for normal street driving. Once a tire exceeds about 40 psi, it is toast on the track until it completely cools/recovers overnight so that's the magic number you want to avoid.

Also, and this too is just my humble opinion as well, I think the quality of Pirelli's annual calendar far exceeds the quality of their tires so you may want to consider alternative next time around...........Good luck.

 

+1000.

I've tracked with so many people who cook their tires and leave the pressures unchecked. You won't believe how fast the air will expand inside, bumping you up into the mid-40s in a matter of one or two sessions.

I'll never forget one guy in our advanced group with an E92 M3. He would adjust his tire pressure to "the recommended 37 psi from the bmw dealership" before hitting each session, and he ended up toasting them right off.

 

Get a pyrometer. You will quickly learn the correct pressures.
You'll end up faster and safer too.
Good Luck

 

Yes,planning to do that. The wheels and tires are being stored presently. It is 110 F now for the next few months, so my track days are over until the fall. I am certainly lokking forward to experiencing the R compunds.

 

Thanks a lot man... I will follow your recommendation. I am no longer using Pirellis for track days, I have switched to Nitto Rs.

 

I instructed the dealer to send them back to Pirelli....but they threw them away by mistake.

 

I've been thinking of getting a pyrometer. Been reading up on the subject. Very interesting. But also a huge hassle and kind off black magic for an occasional trackday driver.
Always happy to learn though if you've got things to share about this ...

 

Pyrometers are easy to use, and that is the only way to get a correct tire temperature for the track. The trick in using one is you have to get your tire readings FAST, because they cool down quickly once you come off-track. Just as soon as you come off track and and can safely pull off into the pits you want to get out of the car and shoot your tires, recording the left tread edge, the center and the right tread edge temps for each tire, then write them down a chart you have in the car (again, quickly on all 4). You want your temps as even as you can get them across the tread so if the middle reading is higher than the edges, you let some air out, if the temps are hotter on the edges than the center - air goes in. That's pretty much the basics of them, and then finding the optimum target pressure for your particular tire.

Plus, you can use the Pyro to check your Furnace in your house when its acting up or taking a reading on your forehead after you just cut the yard on a hot summer day so you can tell your spouse how hot you are

 

Longacre documentation is very insistent that IR is not a valid means of measuring tire temps.
They say you need a probe to get true temps inside the tire where the heat builds up closer to the belts.

Also did the OP ever state what car he has?
4s or 2s?

If a 4s, that may explain why GT cars stick with RWD.

 

It's hard to get readings quickly on a DE day. However, just get to your pit area as quickly as you safely can. The temps across the tire will still tell you everything you need to know.

I look for an even progression across the tire. Depending on camber your inside could be hotter than the outside. That's OK. Your center reading should be between those two. If it is too high let a small amount of air out. If it's low put a small amount of air in.

You will quickly learn a good starting point. For example for my Lotus it was 2 pounds under street pressure to start the day.
Don't over think this. Just get it close and have fun!

Good Luck -

 

Good to know that the OP stayed safe as tires deteriorated. Heat cycled R compound for track for experienced drivers for sure, but not so sure that P Zeros are as bad as many on forums assert. I do not have the extensive performance driving (and no racing) experience of some members on this thread, but simply relate my recent experience with P Zeros. Seems like OP's tires became very overinflated during his session. My reference is: P Zeros on my TTS started an 80 degree plus ambient day track session at 34/42 and within a couple of 1.5 mile laps the car got progressively squirelly/unstable, especially in corners, but also straight line slowing from about 135 to 65 at the end of the front straight within about 400 feet. The TPMS read 42/52. Adjusted pressure down to 32/36 and the car ran several more half hour sessions in 85 degree weather no problem despite further, modest heat-inflation.

Tires are one of the least costly key components so why do Porsche, McLaren and Lamborghini fit them on their cars? Perhaps Pirelli gives them the tires and although I could be wrong I doubt that any of those manufactures would compromise their performance standards for free Pirelli tires. They could just as easily fit Michelin tires.

Last week I had the occasion to do about a dozen laps on an admittedly cooler day of about 72 degrees in a Huracan on the same track with no problem on P Zeros. Had a demo lap in the Huracan with an instructor at the end of a multi-lapping day with stability control off so lots of drifting, but much faster than I drove the track and no problem with the tires.

My P Zeros have 7000 miles on them and about 100 miles of track sessions on hot days and still have evenly worn tread that passed a tech inspection for my first session with the local P club. Yes, the tires had rubber marbles flattened onto the tread after the long hot day sessions, but they have since come off and I have had no tire balance problems as a result. I doubt that I drove my car as fast through corners as many on this post do, so that may account for the modest tire wear on my car, although I ran with 991 GT3's on R-compound tires in all corners, very probably due to my AWD, not my driving skill.

Final comment on P Zeros is that they run them on all but GT3's at the Porsche Sport Driving School at Barber MSP and nobody had problems during two days of many laps.

 

Andrew I think you hit the nail on the head. You mentioned 7,000 miles on the tires. At that point the tread depth should be reduced enough. At full depth the tires would be more squirrelly thereby generating increased heat.

Does Porsche used shaved Pirellis at their driving school?

I really want to attend their school at barber before I start pushing my new GTS around.