freeman

So Chuck

Which 991 do you have so much insight with? Give us a pic

wanderfalke

Could the higher pressures yield better mpg figures as selling point? Porsche knows most of us will run the correct pressures for the current conditions. The same way I never use the auto off feature to save gas. My dealer inflates the rears to 41psi cold, that is not compatible with commuter duty on broken pavement. I am still trying to find that sweet spot. The 4s model with the nannies engaged always seems planted so it is hard to tell when the car is starting to break loose.

Penn4S

I also have a 4S with Sport PASM and PDCC so it too always feels like a cheetah on the road. I experimented with different pressures and settled on the 32F&36R cold pressures for best ride and excellent grip. I am happy with this setting on my Michelin PSS.

john45in

I settled on 29F/32R cold. Warms up to a very nice ride.

woodrow

I too dropped my factory setting of 48r 41 ft on the 2015 991 gts coupe trying 39r 35f going out for a test drive soon i sure enjoy chuck911 threads as well thanks guys cheers from nevada

chuck911

LexVan replies:

freeman replies:

chuck911 replies: You're on the right track.

woodrow

chuck911

In all the 7 pages and 3 months of this thread only a very few have bothered to actually try running a range of pressures. Axxlrod back on page 5 post 63 had exactly the same experience I've described where relying on cold settings combined with sporty driving yields very high pressure that results in the car skating around. Dropping down to 35/38 he noticed a huge improvement in ride and grip, but that was starting from a very high overinflated level. Even 35/38 is still towards the high end, especially if still making the mistake of going by cold pressure. 35/38 cold could easily result in the high 40's hot, which puts you back in skating around territory.

Notice that lunarx, post 72, does not like pressures above 36, likes the feel around 32-33 better, and this in spite of the fact these are hot numbers that result in much lower cold pressures that set off TPMS warnings. So even bleeding yours out to 35/39 is still high and you could stand to try a few lbs lower- based on what a guy who actually owns a 991 says.

(I doubt that last bit applies to you. Just thought I'd throw it in there for the few who think the veracity of what one says is determined by what one owns.)

joew7777

Just came over to a 911 S from Cayman S and I am doing autocross not track. I like the lower pressures but am worried about rolling over too far on tire with Pirelli P zero and having trouble figuring out how far over is too much. I have slowly added up to 35F/39R warm and still seems to be rolling over pretty far. Lots of good information here - I wish everyone would be more positive to others.

Archimedes

The only problem I have with your post is the idea that you should select pressures solely based on feel. I've run pressures that felt great in tires that wound up cooking them prematurely, and I've also blown tires and damaged a wheel running lower pressures. IMO, there's more to consider than simply feel when selecting a tire pressure, though I do agree that some of the pressures mentioned in this thread seem high to me. I also focus on hot pressures, and the ratio of hot/cold.