Do I need this much pressure?

[wbwanzer]

No problem.

 

[SubLGT]

Looking at that table now, I see for my S3 sedan with 225/40 R18 92Y normal load (2/3 people) front pressure of 38 and rear of 35

What is "2/3 people" ? 66.6% people?

 

[wbwanzer]

Yes.

 

[PandaBear]

My recently purchased 2019 Audi S3 is speced on the door placard for 41 psi. The tires are 225/40ZR18 Continental DSW 06. 41 psi seems an awful lot of pressure to me. I've been driving a long time and don't remember ever having a tire need that much pressure. The Audi S3 (think A3) is a small car weighing about 3500 pounds. My Kia Sorento which is much larger and weighs about 4100 pounds only calls for 34 pounds.

So I realize that the S3 is a sporty car. Is that why it calls for 41 so that corners can be 'carved' at higher speeds? I'm not racing, tracking or auto crossing the car. I push it in corners now and then but I mainly wanted this car for the fun acceleration. If it takes me a tenth of a second longer to come out of a corner, it's no big deal. So can I run 35 pounds without problem? I always thought that under inflating would cause the inner and outer edges to wear. And over inflating will cause the center tread to wear. The ride from the rear suspension is a little harsh anyway, so 35 would help with that. So do you folks see any reason why I couldn't run 35 pounds in all tires even though the placard calls for 41?

As always, thanks for your knowledgeable input.

FYI on my IS250 this is the front tire size, and 38psi

 

[UG_Passat]

There's always a maximum pressure marked on the tire itself. Running close to that will have the best mpg, though handling may suffer.

When you go to Autocross, if you don't have R-compound tires, they recommend inflating the tires to the max cold pressure on the sidewalls.

 

[UG_Passat]

On my car, when I have 215/65r16, the pressure is 38 psi, same as when I run 235/50r18, for AWD.

But one can always do the tire chalk test for pressure.

 

[Jetronic]

When you go to Autocross, if you don't have R-compound tires, they recommend inflating the tires to the max cold pressure on the sidewalls.

Isn't that to increase sidewall stiffness and reduce slip angles? Autocross is all about quick reactions and some classes don't allow putting stiffer springs.