drcollie

You are probably over-driving those tires. Time or a set of spare wheels and some Cup Tires.

Mr. Turtles

RobC4sX51

AAK GTS

This is my experience at Homestead Speedway in March. I purchased the car pre-owned a couple months prior and did not check the alignment so I can only assume it is set within spec.

The day before the event I researched tire pressures for the stock P-zero tires and had a base line to start with. By the last session I was using hot pressures of 34 front and 38 rear. The tires are in good condition after the 1hr 45min of total track time. I believe I could have brought the pressures down 1-2 psi to increase tire grip.

What was the front toe set at? Too much toe out and that will kill a tire faster than aggressive camber.

Inbyten

That's roughly what I was running on my p zeroes last year over 5 track days with no issues.

My alignment was performed 3 days prior to the track weekend. Toe was in spec (zero?).

Semitone

I just thought I would add my experience with the Michelin Pilot Sport 4S on my '18 718 CGTS. Got the car new, put about 3000 street miles on at last summer. Then I signed up for an AutoX event, followed by a DE event last Fall. I loved the tires for the street but this Spring, when I checked my tires I saw some serious chunking along the outer edge on the left front tire. (Both AutoX track and DE track ran clockwise) I am not exactly sure if the chunking happened at AutoX or DE. The AutoX event was prior to the DE event, and although the car was inspected pre DE I guess the chunking could have been missed. IIRC, I ran 33/37 for Auto X and probably 30/36 for the DE event. The total miles on the tires is about 4000.

I'm relatively new to these tires and track events, although I did AutoX in two other cars last year without an issue. I'm pretty sure I did some curbing during the DE. Well at his point my tires seem to be toast since I can see what look like plies in some places where the tires were chunked. I did all of the above on the stock camber setting as the car was delivered.

I did think I would get a 2 or three more events before these tires needed to be replaced. Still not sure if it is 1.) my driving, 2.) my setup , 3.) the tires just don't do so well on track or 4.) other.

When I bring them in to be replaced II'll see what my shop says and report back if they see more than it's share of issues with the PS4s.

SpeedZ

So having gone through the same issue recently, I think running 32psi hot in the front tires is just too low. I was starting to get some really bad front outside edge wear when running the tires 32/36 hot... On my most recent DE I bumped it up to 36/37 hot and the front edge wore a lot less and more evenly overall. Hopefully I think I've corrected it before doing major damage to the tires and hope they will last quite a bit longer.

So far they have 4 Autocross events, 2 track days, and 4000 miles on them and look to be at about 70% life left at the center, but the edges got worn down a bit too much from two autocross sessions + 1 DE at 32psi.

I'll also add, I much prefer the handling at more equal PSI settings than the staggered setup that Porsche recommends, for the track. The car is much more neutral in handling.

Rapter

why does Michelin recommend 35-37 psi all around for a 911 on track?
I too just finished a track day and my c4s started to chunk the driver rear tire (clockwise track direction) to the point that just a small amount of cord started to show.

interesting... the Outside edge only chunked across 10 tread blocks. And the cord appeared on 1 block.

I was running 32f/36 rear and the fronts are fine. Just the 1 rear chunked.

BSO

This is an old thread but according to the driving coaches at the Porsche Atlanta Experience, they get 300 miles use on tires (likely the rears).

These tires are made for grip, it’s a wonder people get over 12k road miles on such a soft compound.

X51

I chunked a left front new MPS4 at Road America last summer and got a replacement tire from Michelin. Had to provide the sidewall stampings, mileage on the tire and photos, but got a free tire replacement. I was running 33/38 cold on my GTS. No curbs, just a lot of cornering. I've run Michelins exclusively and have always found them to be better performers than Pirelli P-Zero, but the chunking has disappointed me. Increasing my pressures by a couple pounds at each corner has seemingly helped my latest set wear longer and more evenly.

dsddcd

As a long time instructor I see this ofter, students honing their craft have a tendency to over heat the front tires by dialing too much steering angle. We are programed to add steering in a push but that is the wrong response. You want to unwind to regain traction then as grip is restored start adding steering angle.

Additional I have found the PS4’s require more camber that the PZero’s to achieve more even wear.

i would recommend getting a pyrometer and checking the tire temps you can pay for the expense of the probe very quickly.

I found the 2.0 deg front and 2.2 deg for both to be a good in between for my setup and I run a 2 PSI front to rear tire pressure differential shooting for 30-34 PSI for a hot lap.