ChaosHokie

Hi all,

So I got a new set of MP4S N0's installed on my 991.1 C2S back in ~March (2021). Then I did 3 HPDE events (multiday) in the first half of the year and just some occasional driving around since then. After my last track event, I noticed a little bit of wear on the outside of the front tires, but didn't really pay that much attention since the tires still had plenty of thread left on the wear indicators. Fast forward to this month, where I took the car to the local independent for annual maintenance. When they got it up on the lift, it was clear the front outsides were corded. The rear tires (no pics, sorry!) look perfectly fine.




Besides adding a ton of negative front camber + an alignment, anything else I can do to reduce this in the future? If I add negative camber in the front, will it be fine for daily use or do I need to keep swapping the alignment after each event? If it matters, I'm in the PCA "blue" group for HPDEs. Am I overdriving the car? Do I need to change something about how I drive on the track?

I'm very tempted to now look at getting a set of dedicated track wheels and tires, but I honestly haven't a clue about tires that would be cheaper or would wear better on the track.

WP0

I would venture to say that if you ran with your front tires underinflated, that is a major contributor to the outside cording.

ChaosHokie

From my notes, they were running around ~32PSI hot for all the events.

WP0

Yes, but what was the starting PSI? If you started at 24 and ran them up to 32, the first session that it took to go from 24 to 32 could cord them.

ChaosHokie

Oh interesting! Definitely ran them a bit lower on some days than others to get warmed up. So run them a little higher, pit and then dump some air when they get too high?

snake eyes

You ran them way to cold... it sounds...
I run 28-34 in my Cup 2's

asellus

The MP4S is a street tire, specifically a high performance summer GT tire. It is not a track tire. Using it as one will lead to drastically reduced lifespan and, in many cases, delamination like you have pictured and like what I have pictured below. It and previous generations of it are fairly well known for delaminating when subjected to track use. They just aren't built to handle this kind of heat.

Below is the front left tire after a day in a low speed course where I understeered exactly twice coming into turn 1, which is a flat 90-ish degree right hander. Roughly 80mph entry speeds -- we're talking "high speed autocross" kind of stuff here. I would never consider taking an MP4S-equipped high powered car to an actual high-speed track, like BIR.



Barring actual issues like inappropriate tire pressures or alignment, the MP4S will only take you so far. They are quite unforgiving for novice drivers in terms of wear. Smooth out your inputs, work on a more optimized racing line, slow down entry speeds, and you'll likely see better life, but again... there's only so much they have to give.

WP0

Yes, exactly. Start at 28, and warm up to 35, pit, then drop to 28 again. . . repeat until proper hot PSI reached. . . but if you go too long between sessions, you need to start the process over again. . .

spdracerut

Negative 3 degree camber is also a good starting point. I've been running this on all my cars with even wear even with mostly street driving. Granted... I corner faster than most people. As others have stated, tire pressures and this tire is not a true track tire are also contributing factors.

DC991

That is just what MPS4's do as you get faster when you track them. They are sufficient when you are first starting out but not so much when you get faster. You need to have at least -2.5 degrees of camber up front which on a 991.1 requires camber plates to be installed (cheap option) or GT3 lower control arms (expensive option) and it will reduce that wear but it will still happen over time on that tire. Once I switched over to Cup 2's I didn't see that kind of wear anymore. I went through several set of MPS4's that looked almost brand new everywhere but the outside edge which would be completely worn out. I get double the track life out of the cup 2 then I did with the MPS4

AdamSanta85

I've seen this happen to MP4S's too, not just 911's. They just aren't really cut out for track duty. Cup 2 is the move for a street/track tire.

good2go

I trash a set in one day. I think the only solution is to adjust camber and turn off any traction control.

trashed tires, but I bet you had fun.

enzotcat

What pretty much everyone else said is valid. I would trash MSPS 4S inside of 40 20-minute sessions - what you’re showing is pretty typical w.r.t. the PS4S on track. They’re street tires, and just not resilient enough for the track. I also have my front and rear camber maxed out at max negative camber, and run in the black group in PCA. In contrast, I have gotten some 22 20-minute sessions out of Dunlop Sport Maxx 2 Race tires, and a similar number out of Cup 2’s. They’re rated for less life than the PS4S, but will outlast them on the track. They’re not as good in the wet, though. That said, you definitely do need to be a little careful about under-inflating them at first. Rather start a little higher, and then bleed air out halfway through your session, or at the end of the 1st session.

As far as max negative camber on a stock setup is concerned, what you will find on the street is that the car will wander a little bit, but not very badly at all. I’ve also got a little more toe-in than stock if I recall correctly, and with the combination of those two, I don’t really notice any problems on the street.

BSO

The instructors at the Atlanta Porsche Experience stated they got 300 miles from their street 911 tires. So your wear is no surprise.

Nothing is inexpensive with a Porsche, including tracking. Haven't tracked mine but have been up to the Alabama PTX several times and burned up their tires and cars. Now that was fun.

usccharles

my experience with front tire corner wear (with probably 20+ track days and nearly 10 sets of tires) is that faster corner wear is a good sign that you are understeering your 911. This 911, surprisingly, tends to understeer. it has alot of power and if you don't trail brake correct to corner, you will power-understeer into corners, making those front corners wear out super quick. I've had days early on in my track days where I would wear out my tires after one track day, not because the full tires were worn, but because those corners wore down to the cords.

Now with some track driving experience, I have gotten much better at trail braking into corners. This helps get the weight more distributed to the rear, so that rather than understeer pushing the car into the corner, you are properly driving the car through the corner with the weight on the rear tires, at the oversteer threshold. This will greatly help with front corner wear. if one can learn to trail brake consistently, I've managed up to 3 full days on cup 2s, about 15 20 minute sessions, before the tires had to go. The front tire corners were still first to go, but I managed to wear flat the rest of the tires too.