991TurboS

I've use the comfort settings since I bought the car. Who uses the performance settings?

viperz06

comfort settings here.

Riz

What are the comfort settings? I thought it was regular settings and high speed settings.

Carcam

The standard settings are 34/43 front/back, part load and 37/47 full load. Comfort settings are 31/36.

My tech told me to keep it at the higher settings to prolong tread wear and have less tire noise. I split the difference and run 32/40. It seems to ride well at that setting.

speed21

I'm running cold settings at 37 front, 42 rear. I found lower than felt a touch squirmy. Under 35 on the front definitely felt too loose for me. The tires are 20" and very low profile don't forget so there is the rim to protect too. I also ran my previous 997tt with 19" at the same pressures and they are 1" higher in profile. Other thing is the tires wear more evenly across the tread width I find.

991TurboS

So funny how this thread lay dead for over two months, then gets active!😀

Karl911

I just run MSC2 at 30/35

speed21

These are really track pressures and track tires though. I personally wouldn't fancy driving them on the street as a dd tire tbh. Been there done that. You really need two sets if you do road and track. I recall the 19" MPSC's which I used as my second wheel set on the track for my previous 997. Upon advice from other users of r tires I initially ran those at 32 and they squirm around until they reached temp. Didn't produce the best times and wore pretty crap on the outer edges even with a track alignment. When I fitted my second set the Mich tire tech there on the day asked what pressures was I running after looking at the old ones that came off and when I told him he said 32 was too low, use nothing under 35 and boy he was so right. Times and tire wear improved and the car steered so much better. It may be the same with the 2's but if they are 20's I would suspect that at 30 that is on the low side esp for the steer.

Need4S

Question. If the car is too "loose" at the rear (i.e. oversteers too readily), do you increase or decrease the amount of air in the rear tires relative to the front? In other words, do you increase or decrease the difference between front and rear tire pressures?

Karl911

I run my MSC2 s at 32/35 cold for daily driving.
Track day start at 25/27 cold
After driving for awhile run at 35/39.
P zeros should be run at 3 to 5 psi higher.

boxer-11

With N0 Pi Zeros (haven't had any N1's yet but I hear they are coming(?)) based on track experience I think anything over 40 PSI in the rears and the back end grip starts to feel greasy to me.

On that basis I set 37 for cold street use pressure because I've observed that in my version of driving about the place I pick up at most 3 PSI on most journeys as the tires warm to the task.

I heard a bona fide pro race engineer who knows Porsche really well argue that the reason for the lower front pressures is more about liability than performance -- the PAG lawyers want you hitting the hedge nose first more than tail first. Thus the recommendation to set lower front pressure, biasing car set up towards push-first. Seems prudent for street use to me so I set the fronts to 34 cold for the street.

Related but not directly to the points in posts above. I do have my own pressure question for everyone. If you are running winter tires, what pressures are you using for those??

I have Michelin Pilot Alpin PA4 (N0) tires on there right now and I'm running them at 31F/36R -- seems like the TPMS is happy with that when I ask it about fill pressures. Just wondering what others do.

MaxLTV

That's what I would do as well. Take GT3 street pressures on the same tires and adjust for slightly higher weight. Higher pressure on street tires (+2-3psi) to compensate for flimsy sidewalls

worf928

A decrease in pressure will increase grip (up to a point, of course.)

A drop in rear pressure may result in less oversteer.
Alternatively, an increase in front pressure may offset some of the oversteer with some understeer.

Dropping pressure too much will result in destroyed tires: side walls and outer tread. Outer tread because that's what you're using if the tires are underinflated. Side walls due to rolling deformation causing heat and at high speed not enough time between revolutions to radiate heat.

Pressure changes can slighly offset any 'natural' imbalance due to weight distribution or tire sizes. Porsche undersizes the width of the front tires to ensure that there is some understeer. 911's big a$$ needs more meat in the rear, but the fronts are still a bit skinny.

Visceral

Its easy to buy an infrared thermometer and measure your tires tread temps (inside, outside, center) after spirited driving/track time. Typically the outside edge is hottest, and the inside edge is coolest (unless you are set up with a *lot* of negative camber), and you want the center midway between them for maximum traction. The temperatures front-rear tell you a lot about which end is having to work harder. For instance, if your front tires are working too hard, depending on temps across the front tire you can also either raise pressure in the back or lower camber in the back (for better straightline traction but worse cornering), and this will increase oversteer/decrease understeer.

For the street, I'm mostly interested in keeping tire wear even across the tire. I think thats 34/36 right now with stock PZeros.

Randyc151

+1, except on track I bleed pressure when they are hot to keep it to 36 max. They get a little greasy higher than 36 on a hot day, IMHO.

Cup2 tires are totally different from original MSC, so don't draw any comparison whatsoever. I always use the "comfort setting" because the factory setting is designed for ultimate security from tire blowout at the car's top speed with a full weight of 4 passengers and luggage at max. It's selected to prevent the "Ford Explorer" lawsuits, and the cover Porsche's *** in case of a blowout. It's actually pretty despicable that they recommend this and ship cars this way.