For those of you that run MPSCs at the track. Any thoughts on how many days are left on these-



Yes I know different tracks and driving styles will affect tire wear. Just looking for some insight as to the wear characteristics of the Sport Cups.

Thanks.

 

I think they look fine for at least a day or maybe even two (if dry)

But if you planned a nice DRY track day, paid your entry fees, and took the day off for it. Get a new set. The fronts and rears have the approximate same ware pattern so it's either your 2nd rear set compared to the 1st front, or you have not tracked them a lot. Anyways:
Why take the risk for one more day with them if you are in doubt. It's such a pity if you find yourself driving for 20 minutes and sliding all over the place. What will happen is that the tire will loose grip and after that the fun is gone (or just starts for others ;-) Here my tires after i lost their grip, but it's also about how many heat cycles they had and i did not count those.

 

Berger, the second tire down in your photo is worn worse than the other front. You should be swapping them from left to right after each track day. As far as wear goes, your tires look like they have seen 5 -6 trackdays or 22 -26 heat cycles. for some drivers they are past their prime and done. For some others they are just done now and should be replaced. You could get 1 - 2 more days of use if you want to. If you try for 3-4 more days then they will cord and you might be replacing sheet metal as well as tires. What ever you are comfortable with.

Q & A How much negative camber are you running? It looks like a lot. And it looks like you use 34-35 pounds of pressure in the front??

 

Thanks for the insight. Can't answer the questions as the tires were bought with the car. I've not run them yet.

I don't have the current alignment specs, either.

It does look like the fronts were a bit high on pressures. To me, it looks like the rears are at about 2 degees. Not terribly aggressive. Maybe the pressures were low when the previous owner ran them, which would account for the roll on the edges.

If you're referring to the fronts and camber, I think that's just the picture making the wear angle look crazy. The tires are actually worn somewhat evenly.

 

Without history it's tough to tell, looks like tires 2 and 4 in the stack are worn a bit more than the other two, if say you were going to Mid Ohio just put those on the right side of the car which will get less wear and it should help even them out some.

Also, what's your skill level as a driver? how will the car be setup when you track it? All could play a role in how much is left in them.

FWIW, the set that came with my car looked about like yours, however they were shaved new to only 3/32 to begin with and only had 7 heat cycles in them according to the previous owner. I proceeded to put 7 very long heat cycles in them at Mid Ohio a couple of weeks ago (30+ min sessions) and they're still looking like they'll have another weekend in them with no problem in my opinion. They stuck really well once up to temp, ran hot pressures of 31/33 and really liked them there. Felt grip drop a little by the end of the day but I was also pushing harder so maybe that was the difference.

All of that said, PSC's are pretty notorious for heat cycling out after around 20 hard sessions, The set on my M3 a few years ago I got about 24 heat cycles before they started to really slide all over the place, there was still pleanty of rubber left on the tire though.

Andy

 

I think that's the answer I was hoping for. Thanks AudiOn19s.

These were also shaved when purchased. If they wear similarly to RA1s or NT01s, I was thinking a weekend would probably be fine with what is left.

It would either be Mid Ohio or Putnam Park, and the right side of the car would certainly see the tires that had less rubber. As for my skill level, I'm sure I could drive these to cord in a day if I wanted to, but this would be my first time at the track with the GT3 and I expect I'll be back to super smooth while getting to know the car.

I used to have an e36 M3 and was turning 1:46s at Mid Ohio and 1:21s at Putnam, which I really had to push the car to get. I doubt I'll have to take the turns quite as aggessively to see those times in this car.

 

Good info. I'm also trying to figure it out since I've heard so much about the loss of grip before being worn.

I'm on my first set, and they still look good and feel good.

How sudden/brutal is this loss of grip when max heat cycles are reached? Or is it noticeably gradual?

 

One thing I noticed with my old MPSC's is that the fall off is dramatic once they heat cycle out.

I had a set that wore down very well. However, they had been cycled enough that they were both at the end of their "cycle life" even though there was some tread left. Tread alone is not a good indicator of how much "Life" if left in them for the track. For the street, that is what the wear bars are for.

The other thing I would look at is the tire's "born" date. Look at the side wall and find the MFG date code. If it is over 6 years old, I would not track them.

just my .02

 

I've got 6 track days on my MPSCs which I installed this year. 2 days were advance driver days with nearly 4 hrs track time per day. Still sticky and capable of more days but weary of the famous 'drop off' in performance .
Based on your pics, I'd personally use them since as you say you're still getting used to the car and won't likely be taking it 10/10s. My advice though is to have a good track inspection, tighten everything up, inspect shocks, check alignment or align to ideal specs, etc. That's what I did last year when I bought my 996GT3 last year from a dealer and took the car with dealer temp papers to a track in NY - Monticello. Enjoy your 'new' ride.