Manifold

What hot tire pressures are you guys finding to be optimal ON TRACK with the MPSC2?

Edit: Argh, sorry I messed up the poll. Didn't intend the overlap between the 2nd and 3rd (and 6th and 7th) choices. But please just pick whichever selection fits best for you.

MayorAdamWest

It would help if you specified front or rear

Mike in CA

First AX of the season yesterday. Had good success keeping pressures in the range of F30, R32 HOT. Neutral handling, no sidewall rollover. Grip seems to fall off with higher pressures. The circuit TPMS mode comes in handy for monitoring pressure without getting warning messages from the standard mode settings.

Manifold

The poll separates front and rear, and you can make a selection for each.

SamFromTX

Voted for the closest but my optimum pressures, hot, are 29/32. Higher than that and car slides. Lower than that and the car slides. Different feel between under and over inflated tires.

Manifold

From the Michelin site, for the MPSC2:

http://www.michelin.co.uk/tyres/mich...ot-sport-cup-2

INFLATION PRESSURE ADVICES

On the track for majority of car (*)
Cold tires
• Inflate the MICHELIN Pilot Sport Cup2 with a pressure between 1.7 bar (24 psi) and 1.8 bar (26 psi) front & rear
• Never allow the pressure to be below 1.5 bar (22 psi)

Hot tires
• The optimal operating pressure of the MICHELIN Pilot Sport Cup2 must be between 2.3 bar (33 psi) and 2.5 bar (36 psi) Front & Rear
• Never allow the tyres to run below 2,0 bar (29 psi) HOT

Road use
• Use the cold pressures recommended by the car manufacturer

* This information applies to the majority of cars regulalry used on circuits e.g: Audi R8, BMW M3 E90 / E46 / F80, Porsche GT3 / GT3 RS / 911 Carrera / Boxster/Cayman, Renault Megane RS, Subaru Impreza/WRX/BRZ
For all other cars and in particular for heavy cars or for any other specific information, please contact your local website www.michelin...

SamFromTX

Yup, saw it before. Not sure why but I am slower with less grip at 33+, especially for the fronts.

Zulu Alpha

I run these pressures and agree. Any lower and the front end will jitter like crazy. Not a good feeling. Also, what I like about these pressures is that the sidewall absorbs much of the bump while the PASM is switched on.

NateOZ

Could be your camber settings? You're potentially not using the full width of the tire at higher pressures? Do you have a pryometer? Measuring outside, center and inside temps at different pressures will help dial this in. Pressure is often does as a quick fix because it's the easiest to do at the track, but it really should be done last.

malmasri

The magic number for best performance seems to be 30 all around, not 1 pound beyond that.
I did not believe it initially but discoverd that myself, 32 or more and I get understeer under heavy breaking, At 30 my 991 Gt3 is perfect, BTW I have Dunflops, and my buddy has MPSC , we both ran 30 hot this weekend at Homestead, the MPSC are a hair better and both cars are withing .5 sec of each other.

Hoopumpers

Agree lower is better. 29F/30R

Zulu Alpha

I tried 30 all around and got a lot of understeer

Manifold

Did my first track day in the GT3 today. Will report on that after the event ends tomorrow.

Meanwhile, I spent a lot of time fiddling with tire pressures, and am falling into the 'lower is better' camp.

Bearing in mind that there's some variance in the accuracy of tire pressure gauges, I'm finding that the rear starts to have noticeably less grip at 33+. I'm going to try to 30 or 31 rear tomorrow.

Harder to say where the optimum for the front is, but somewhere around 30 is feeling best so far, 29 might be better. Seems like 31+ front creates noticeable understeer, and higher pressures in front also result in the tread not getting worn and sticky out to the shoulder (with -2.0 camber). So I'm going to target 29 front tomorrow.

Should also note that I had considerable instability under hard braking, which felt like it was mainly due to the tires being too greasy, though insufficient rear downforce may be a factor too (time to try Crawford wing?). Hoping that the lower pressures help remedy this.

Thanks to all who responded to this thread and poll. Reassures me that I'm not crazy running these relatively low pressures!

malmasri

front swaybar setting should be adjusted

malmasri

Manifold: Should also notice that I had considerable instability under hard braking, which felt like it was mainly due to the tires being too greasy, though insufficient rear downforce may be a factor too (time to try Crawford wing?). Hoping that the lower pressures help remedy this.

Thanks to all who responded to this thread and poll. Reassures me that I'm not crazy running these relatively low pressures![/QUOTE]



That should go away at lower pressure....