So I made it out to COTA yesterday for the first time on any course. It was absolutely wonderful. I ran new PS4S tires and I was in shock how well they gripped. Never have I felt that much of a lateral G force. Now for the question. Did my tires melt on the edges? See the rim of the tire almost looks like there is a line there. Nope it was not there before.
I ran 33 and 38 cold while it was high 80’s for a change. I don’t remember what they were at hot.

 

Pressure was high when hit. Those tires, according to Michelin, like mid 30s HOT for max grip. So you def didn't melt anything, you just wore the edges while cornering. More air pressure cools your tire. Your shocks also have poor dampening, like mine do, hence the buildup on the rear of the sipes. Check the tread area well, do you have any chunking or tearing?

 

Wow, I don't even run my street tires with that much pressure.
You should shoot for that hot. But, P4S tires have soft sidewalls so you'll need to do a warm up lap to build some pressure back up.

 

I will need to check the tires in the light tomorrow, but my tire sides look like yours.

This was my first HPDE event so I am still learning as I go.

 

I’d worry about driving lines and getting a level of comfort first.

Your tires look fine to me. Keep going with that pressure. As you get faster the line will start dropping further and further down the sidewall.

If anything drop pressure a bit and then build it back up till you start wearing the sidewall away more. As you get faster you can mark the sidewalk with chalk to gauge how much more pressure you need.

Understand that most people tearing out chunks of their tires have really bad slip angles and are using too much tire to turn.

 

All very good advice above. Your tires look very typical of a street tire used on track within its performance margins. What you don’t want to happen is to have them start looking like those in the second post. As you get faster, you’ll add more heat (+10 PSI is not uncommon) and start to push the limits of what a street tire can handle. About the same time, you’ll also start exceeding what the stock brake pads/fluid can handle. At that point it’s time to think about a dedicated set of track wheels, tires, pads.

 

That's normal track use wear. It will look normal again after some street miles. When you hear people talking about the rubber marbles on the track, this is how they get formed from the tire rubber getting hot, sticky, and balling up, then coming off.

 

Well this brings up a question I was debating at the track this weekend...how much should you air down your tires from the recommended (cold) pressure before you go out? Recommended pressures for the 997 are based on 19" wheels, but I run 18", which throws off the calculation a bit, but I was gaining a LOT of heat in the tires (Pilot Sports) after 20 min on track...

 

I ran PS4S for four years on a Boxster before moving to a 981S and a set of dedicated 18s with Hankook RS4. The wear looks typical. The "cuts" and tears do not. Its late in the year but I'd get as much negative camber in the front that you can get with stock suspension next Spring. Camber plates and/or adjustable LCAs are needed to get what you truly need. Not sure if your car is a DD, but I had -1.8 camber on the front to help with edge wear with no effect on daily driving. I put track pads on for my first DE but that's another thread. In the Boxster 36 was my high target pressure for the front with 27 or 28 to start.

The PS4S are amazing in the rain.

 

These are darn good tires in my considerable experience.

I see wear like this with student sawing wheel through turns. Smooth lines are fast lines. If you are cooking corners and oversteering you will see wear like this.

Just tell the wife you were so darn fast you melted your tires and need race wheels and tires for next trip.

Enjoy the track

 

Air them down as you go. I like 33 front and 35-36 rear. After each session, come off track and immediately check them to bring them down to your desired pressure. Depending on if you drove the car to the track that morning or not, will dictate how much to air down. But you can probably start some where around 30psi on fronts, 33in the rear if they are cold. They will feel and sound like bricks until they get to temp. So give them a lap or two before you push really hard.

 

Take notes on what the weather (sunny, cloudy) and ambient air temp. I've run several track day tires and found they start to get greasy above 37 PSI but it varies by car setup and tire. I use 35 as my target for my current RE71R. YMMV
Some tips.
Make sure the car is in the shade. Yes, any tires in direct sunlight in the summer can raise tire pressure more than you think.
Between sessions the tires may not fully cool and pressures may not fully lower to ambient. You may need to bleed a little air throughout the day to stay in your target hot range.
Some cars are harder on rears, our 911's. Some tracks are harder on one side vs the other. I start my rear's 1 PSI lower. At Pocono I also have to run the left side 1 PSI or more lower than the right.
Check pressures as SOON as you as you come off track. If it's a long ride to get back take this into account. Your measured 35 may have been 37 on track.
It's not difficult and may seem like a lot to do but just take a few notes and look it over during the day. It will become an easy to understand habit.

Good luck!

 

Here's another technical Robert MItchell video on how he arrives at his working tyre pressures at the Nordschlieffe.

Robert's an excellent communicator, i find his subject matter and delivery always easy to digest.

Sorry I cant post a propper link, we have blocks on this stuff where I am at the moment

 

More air pressure cools tires??? It's actually the opposite, especially on track. Excessive air pressure makes the tire firmer/less flexible. Therefore instead of giving and flexing on the contact surface, the tire begins to slide and grate across the surface, causing even more heat and pressure build up, like a vicious cycle.
If fact, your entire goal with pressures is to allow the tire to flex enough to make a softer/flexible contact patch, while still having enough air pressure to support full load without rolling over the inner and outer sidewalls.

A lot of good points already mentioned. The outer wear on the non damaged tires (looks like front tires?) appears normal for track use, and you're not rolling over into the outer sidewall excessively so it appears fine to me.

The other damaged pictures are actually heat blisters from overheating the outer edge, more than likely from a lack of camber but also excessive tire pressures as stated above.

Your full hot pressures are the most important aspect, and I agree on 34-37psi FULL HOT max. All tires tend to start breaking away and grating above 40psi on track, ie "getting greasy". Your cold/starting pressures are always dictated by your hot pressures, as in "I need to be here to get to there."

The easiest way to learn where your cold pressures need to be is to start at say 5 psi under your target hot pressures, no matter the ambient temp. Yes, the tire may feel softer and flex more, but within a few warm up laps it will come up easily and then some. From there, you bleed down to your target hot pressures as soon as possible. Best is in the hot pits immediately after exiting the track, as even a cool down lap may change your actual hot pressures by a few psi, nevermind making your way back to your parking spot etc.

You may have to bleed several times throughout the day if the morning and afternoon temps are drastically different, but here's the real key I always teach new students and clients. Your first morning/day is for data to set your hot pressures, therefore, do not add air at the end of the day if you are running the following day. Because wherever your cold pressures are first thing in the morning, that's your actual cold starting pressure in order to reach your full hot pressures.

Yes you may have tpms warnings on (will probably be on for target hot pressures anyway in a 997), yes the tires might feel too soft at first, but you won't damage them with say high 20's to low 30's psi unless you push them too hard. And after warming up both yourself and the tires for a few laps, your pressures will come up faster than you think and you'll be ready to rock, learn and have fun without stressing about excessive pressures and damage.

 

Yeah, additional air cools tires. Flex of the tire is what causes heat. That's why we motorcycle racers accelerate hard and brake hard on our out laps, and why the cars weave in the warm up lap; to flex the tire to increase heat.

Perhaps there is a limit to to this, but I've never increased air pressure to gain heat/grip.