Greg Fishman

My experience with the MPSC's were that they had a lot of low speed understeer and sudden oversteer in fast corners, and not just when cold. I about lost it at Road Atlanta in a race as I was headed thru T12. Same line, same gear, etc, etc. The back end just wanted to lead. I caught (my life depended on doing that!). Then I used them at Putnam Park and was so slow, went to Hoosiers and picked up almost 2 seconds. I worked with the Michelin engineers at Road America and over the phone to get the right set up and I never did so I gave up on them.

Mike Buck

There are many more sizes for the R1's coming. The launch tires (made starting a week or so ago) are in those two 18" sizes only. Expect all the standard Porsche sizes like seen with MPSC's and some others for vette fitment, etc..

Larry Herman

From what I have found, Hoosiers do not like to be abused, and the smoother you are, the better they will perform. You can still overheat them, but they are light-years better than the older ones. The lighter the car, the better they work. MPSCs like heat; whip them, beat them, abuse them, the hotter they get the more grip they have. The heavier the car, the better they work. Where that crossover point is from Hoosier to MPSC depends on the particular car and driving style.

As a sidebar, the Comps are the right size for my car. Maybe I'll try a set.

George A

That's my exact take on the MPSC's and Hoosier's. I do think that at the limit, the MPSC are much more difficult to drive as they don't give you much warning before they completely let loose. I've found the Hoosiers to be more forgiving, grip starts to go away gradually. I can’t believe that these tires that are so comparable in performance are so different in handling /communication characteristics, but they are.

G.

38D

I think Larry has hit it spot on. When people tell me they dont like MPSCs I immediately know they are not getting them hot enough. Its either a) their car is not heavy/fast enough b) they are not driving hard enough or c) some combination of the above.

Chris Reinsborough also runs MPSCs on his C4. He is normally a top guy in an uber competivie class. Oliver Zitsman also ran MPSCs back when he ran in E (granted, that was before the R6s existed).

Steve Watkins

George, you coming out to ECR this weekend? The R6s wear like iron with my setup and once heat cylcled out have about as much grip. No contest with grip vs MPSC when both are at their best, either you run Hoosiers or wish you had.

38D

Sorry, but this is just not true for heavier cars.

paradisenb

Please define 'heavier cars'. What is the breaking weight for lighter v heavier?

Bull

Having just lost almost 600lbs by moving from a stock (mostly) 993 to my 964 USA Cup, I'm looking forward to comparing the two in the Spring, and have a set of each mounted. With the 993, once I got the pressures and temps figured out, the biggest difference was the price!

Larry Herman

On personal observation and reflection, I think that the crossover weight is probably around 2900 lbs car weight. That is also modified by HP. Having less than 300 will tend to make the crossover point higher, and having more than that lower.

To elucidate, a Club Racing GT3 at 2920, could conceivably run either tire, but that 400 HP would tend to favor the MPSCs. A stock C2 at the same weight would probably be happier on Hoosiers.

And finally, driver style does have a lot to do with this. If you punish your tires, MPSCs, and if you are really smooth, then Hoosiers. The only way that you will really know is with back to back tests.

And just to confuse the issue, 2 of the East Coast GT3 racers in PCA run neck and neck. One runs Hoosiers and the other...MPSCs.

George A

Steve is right about the lighter cars but I was going to question him on the same thing on the heavier cars. With my car, that weights 300lbs more , the Hoosiers are only at most a half a second faster on their fastest lap, which is a the beginning of the session. The MPSC kick in half way through the session and are typically at their best at the end of the session.

BTW, Steve, I'm thinking of skipping the trip to EC and heading out to MSR. Verges is having a birthday party (and showing off his new house) at MSR plus I want to do a little test and tune with the car (which is at MSR). I've already decided to join EC, so going out there won't persuade me. Theres a guy from my work that's also committed to join. I swear, every time I see him, that's all he talks about.

G.

lawjdc

Just to add fuel to the fire all of you have so willingly kept burning, I contacted Hoosier to razz them about not making a 305/30 X 19, and they were very polite and suggested that their 295 is very close in dimensions to the MPSC when mounted on a 12" wide rim, and would be quite sufficient for the 997 GT3, thank you very much.

After all this discussion, I can't help but think that Porsche put a significant amount of effort into the N spec MPSC and tuned it quite specifically for the new GT3. But were the tuning efforts directed towards making the MPSC a better street tire, or was Porsche's main focus lower lap times on the track? I am willing to be my nickel on the better street tire, but I could be wrong. . .

Larry Herman

lawjdc, perhaps you are a little confused? The MPSC is a track only tire. The MPS2 is the street tire, and yes it was constructed in the proper sizes for the GT3, AFAIK.

flatsics

997 GT3 uses an N spec MPSC

https://rennlist.com/forums/wheel-and-tire-forum/329233-michelin-pilot-sport-cup-a-study-in-standard-model-and-porsche-n-spec.html

Larry Herman

Thanks for the update. I guess since Porsche is softening the GT3, it is logical that Michelin should do the same with the MPSC. It is apparent that the "N" spec, which in the past only specified a purpose build OEM tire, now means a very different tire. Unless it's raining, it will not be as fast as the MPSC on the track. Thanks for making things simpler, Michelin.