revolution225

Excuse me for posting another MSC2 thread, but I really can't find an answer to my issue....

I started going out to the track about 4 months ago, had gone 7 times since, it's usually 20min sessions 4 times a day on a technical 3.5km (2min) track. The first track day I used MPSS and then I changed to using MSC2 only during track days. I heat cycle the MSC2 before use but I'm on my third set already and looks like I'm going to need a 4th set soon.

I have tons of treads left on the tires but by third track day it will lose all its grip, front & rear..the outer edge also gets worn out really fast on the front tires....its been the same through the first 2 sets, the 3rd set has 1.5 days on it I'm anxious to see how it will do the next time out.

My car is a 991 Carrrera S, suspension is stock, alignment is slight toe out in the front, -1.6 camber front and -2.25 rear....pretty much a stock set up.

I read on rennlist forum that some people can get 10+ track days out of them, on average most people get 4-5 days AT LEAST out of these tires....but I ask around race shops here, everyone tell me these MSC2 will only last me 1-2 days on the track before exceeding its heat cycle, any tread left (which is a lot) is useless on the track as the tires are super slippery. I find the 180 treadwear extremely misleading.....

Am I doing something wrong? Should these tires last a lot longer than 2 track days?

How many track days does it last for you?

Any other track tires option available for 305/30/20, 245/35/20? Doesn't seem like I have any choices unless I go down to 19"......

I can't keep going thru tires like this if I want to go once or twice a month....gonna need to do a group buy on tires myself!

Any help is much appreciated!

Horizontally Opposed Man

It probably is a combination of several factors that are causing the premature wear.
First whatever track you are using maybe hard on tires that's a big factor.
Second at this point in your driving life you may also be a bit hard on your tires ,no offense ,it's just part of the game.
Third they are not awesome tires durability wise.
Crazy suggestion : buy yourself a set of 18" wheels that fit the car changing wheel diameter in this day and age doesn't really affect handling like it used to .
Tires are way cheaper, after a couple of years on quasi streets gets yourself some Hoosier R7s but NOT UNTIL you really understand car control😀😀😀😀
Welcome to the best addiction on earth and have fun.

kgorman

Doesn't sound right. What do you mean by lose all grip? Are pressures where they should be? What about pyrometer after a session?

Have someone seasoned drive your car when the tires have lost grip and give feedback.

dan212

That is certainly not normal wear and not typical for these tires.

Several culprits come into play.

1. HEAT
2. Driving Style
3. Alignment

Pressures
Are you keeping an eye on tire pressures? Street tires will go up 12 pounds or more at the track. This is nothing like what you see on the highway. If you don't bleed them they will be wildly over pressure and cook that much more. Over-pressure tires will not perform well, can be damaged and are in fact dangerous. Certainly an over-pressure tire will feel greasy. Just as an overheated tire will also feel greasy. You need to start at a lower cold pressure than normal and bleed them out through the day. At the end of the day, you will need to put air back in. Are you checking your pressures?

Driving Style
If you are grinding the outside edges of your front tires, you are understeering and just grind the tires to death. Thats not the fault of the tires. You need to consider your driving style and not try to force the car to turn, tires screaming in protest.

Alignment
Alignment is going to be a compromise. A typical stock alignment is designed to wear well on the street. The toe & camber is set to make the car safer and the car wants to go straight. With a track alignment the car wants to turn. Not necessarily what you want on the street. Typical street alignment will show more shoulder wear and understeer at the track. Typical track alignment is optimized for turning and hard cornering. Track alignment will handle better on the track and wear better because it is optimized for the constant state you are in on the track: turning. Of course, that track alignment also means that the tires will wear more on the street and the shoulders will wear faster on the highway when you are not turning.. You can compromise with a slightly more aggressive alignment. Pick your poison.


If you are wearing the shoulders, you are grinding the tires. Guess what? That produces heat. More heat==more pressure. More pressure+more heat will cause the chemical reactions in track rubber that we associate with heat cycling. And of course all that greasy effect will just mean the tires slide that much more, wear that much faster and on and on and on...

Consider all of the factors mentioned above.

ExMB

1) How are they heat cycled before you get them?
2) What are the tire pressures you are running: cold and hot?
3) That stock alignment isn't helping you.

Olemiss540

Stock alignment is not helping at all. Get a set of camber plates, and run another 1 - 1.5 degrees of front camber. The outside shoulders should not wear drastically different then inside. The cost of camber plates PAYS OFF compared to buying 600 tires every 2 days!

How about a move to a more durable tire like the NT-01 or even the new RE71R? These will not give up much grip at all compared to the MPSC and will definately last longer.

Another side opinion, this early in your driving career, why in the heck arent you running a 180 TW tire? Your car is FAST compared to most everything at a DE, and you are not trying to break your track record, so save money and learn better car control with some sticky 180 TW tires..... A move to an R-comp should only occur once you feel comfortable sliding the car around on street tires. A 991 Carrera S is dangerously fast (sub 7:50 NR times?) with street tires, and on R-comps, can be OUT OF CONTROL in a hurry. What kind of safety gear are you running?

Difool

Consider at least -2 degrees camber in the front. If you need adjustable Lower control arms to get there that will be about the cost of a set of Cup2s
I know a lot of people run 0 toe in the front, and that's what I run on a CS. It might help you be more predictable on turn in and less likely to scrub. Not sure though.
Consider bringing rear camber back at least to the level of the front, to bring oversteer up a bit if you are chonically under steering.
If the bug has bit, a smaller set of rims will give you more economical choices, over the long run (*cackles at the notion of economical*)

But above all else, Get a good coach or instructor in the car with you after talking to them about what you are experiencing.

rlets

It is typical for a new track driver to over-drive the car. I did. It took me a couple of seasons to get my tire and brake wear down to a reasonable level by learning new skills. I learned them by listening to my instructors and catching as many rides with them as possible.

Making changes to the car during this period of initial learning can be counter productive. The suggestions to adjust tire pressures and compromise on alignment are good. But I suggest you resist temptation to attack suspension and brake upgrades. And for sure get some smaller wheels for track tires. I run 17" NT-01, which are cheaper and last longer than the MPSC.

Rich

revolution225

Sorry I forgot to mention that I run them hot 29 front and 32 rear

revolution225

I mean all the grip that I had the first and second day. Pressure is hot 29 front and 32 rear. Temp is between 75-85.

Had an instructor drive it, told me to change the front tires. The edges in front tires are worn.

I'll get some pix of the worn tires when they're shipped back from the track.

Bill Lehman

I recently instructed in a 991. The car had marginal grip and I found out that the Porsche recommended pressures were very high. We dropped to 38 hot and things were much better. I don't think the tires were MPSC 2. Your hot pressures look too low and I expect you're rolling over the edge. Take some chalk and draw some radial lines from the tread down into the sidewall. Drive on the track and check how far down the chalk is removed.

Thundermoose

Your hot pressures seem low to me. Here are some guidelines on pressures and alignment.

http://www.tirerack.com/tires/tirete...nd_Feeding.pdf

Starting out I would think you'd want to run RS3's or the like.

revolution225

Thank you for your feedback!

Just got camber plates from elephant racing, haven't installed them. I'm pretty anxious to try it out. So about -2.5 to -3.0 is a good place to start for the front? How about rear?

My tire options are super limited, if I don't buy something that's in stock, it's gonna be crazy expensive. The only tires that are in stock in my size are pzero, mpss and cup2....originally I just wanted a second set of tires for track and it rains a lot here so I want to save the tread on the mpss for daily driving, and cup2 seemed like a logical choice at the time. I think I will get a set of 19's so I can have a better selection of tires.

Safety.....the track only requires helmet, so that's all I have.....I almost couldn't even get a helmet before my first event cuz no one sells auto helmets here.

kgorman

pressures low! get to 38 hot and call us in the AM.

ExMB

Since you only gave one pressure ..... Pressures should differ between front and rear since cold pressures differ. So far I found that MPSC2s don't like anything above 36 psi hot without getting greasy.