Not sure when mine were manufactured. I did not check and they are gone on their way to Pirelli. I have decided to go the R compund way for my track days. I will not use the stock tires. If I had to use the stock tires again, I would adjust my driving style to minimize the squealing...I think that would actually improve my lap times.

 

Tire warranties are good for either 5 years or 10 years from date of manufacturer and not purchase. Most high quality, DOT-approved, street tires are warranted for 10 years.

Great call on the R-compound for the track. It is the only way to go. As for stock tires on just about any stock car, you would not achieve the best track time by driving below their squeal limit.

 

Based on what I see on TV that is Pirelli Formula 1 style wear!

More seriously, in a 991 you need to start out with much lower pressures - like 32-34 cold- and check after 5 laps to avoid those way too high distructive pressures on the track. Anything over 40 lbs front or rear and they go away fast, especially given the weight of a C4S.

 

These cars are set up from the factory to understeer a bit, and that is hard on the front tires.

One important key to better lap times is proper trail braking.

 

Every car made is set up to understeer. Can you imagine the carnage if they sold cars with a little bit of "auto-x junkie" oversteer? The lawsuits would be never-ending...

 

It was fun until it lasted...

 

After replacing the blown front tires, the dealer could not get a shimmy to go away...until they decided to get serious and inspect both wheels. I have NO IDEA how I did this!!

 

Kerbstones ?

 

Perhaps..but I never went off track, not once. This track has curbing which should not be causing this.
I have to say I am disappointed in how easy it is to do damage on track days...tires and now wheels. I will never use my stock tires/wheels on track day again. Fortunately the wheel can be repaired according to the dealer. Total damage now approaching $1000. I wonder how close was I to do more serious damage (suspension?).

 

Wow! I'm at least glad you found the root of the shimmy/vibration. Geez!

 

I've never seen a wheel bent in that spot before.....a hit hard enough to do THAT should have blown the tire off the bead at the very least. Very odd, I wonder if the metal was weak in that area?

Or the Tech at the dealership just smacked it with a hammer, which is what it REALLY looks like.

 

Funny, I was thinking exactly the same thing.

 

Today I was off and decided to go back to the track. I am only 30 minutes away from it. Gates were opened, track was not being used. I parked my car (not the Porsche) and decided to walk the track (which I have never done before). I inspected every apex at every turn (which I was trying to nail during the track day). I was shocked of how rough, uneven, and patched up some areas were. I actually decided to walk it one more time this time taking detailed notes on how to take a curve while minimizing chance of damaging wheels. I am amazed I did not do more damage. Lesson learned...every new track I choose to race on, gets a walk with note taking prior to placing any wheels on track.


Be careful out there!!

 

FUNNY...My dealership in Phoenix is amazing and I trust them completely. The service department is top notch. They were actually ready to warranty the tire because of the shimmy and the fact that the road force was a bit high. When they replaced the tire with a brand new one and had the same issue, they decided to carefully inspect the wheel. Anyway, I have to say that the shimmy was never severe after the tire replacement. I bet most people would have lived with it never knowing that the wheel had been damaged.

 

One of the reasons I say that looks like a hammer strike is that 20 years ago I had a brand new M3 that took a heavy deer strike, the car had 600 miles on it and the deer rumpled the entire front end and even the roof. Took it to a high end body shop and the guy said the car would have been totalled if not so new, and that it needed a new roof - bu the insurance company will have him pull it and patch it. So he took out a hammer and put a giant smack in the roof and said "now it needs a new roof for sure, no patching".

True story.