lucroberts

I have Bridgestone Potenza (205/255) 17s in my 1996 and the Porsche Sitcker in Drivers column says:
16s: F 36 R 44
17s: F 36 R 36
18s: F 36 R 44
Why the 17s are the only one with 36 psi recommended in Front and Back ?
Of course I'm talking about street drive.

RallyJon

I can't imagine that anyone runs 44psi cold no matter what size tire they have.

95 C4 993

I run 36r, 34f on Bridgestone S03's. Been that way for the past 4 years.

deltawedge

I have 225/40 17 and 255/45 17 and the front gets 36 and the back 38 psi. Works for me.

lucroberts

Thanks Guys

Greg Bell

I run 35 all round on 17inch Continental Sport Contacts - a happy compromise. You get a much better ride on 17's for a daily driver or non track car.

InTheAir

The cold temp pressures are dependent on your driving style (and track/course conditions) and your car's particular set up.

You can start at a baseline of 40 PSI HOT. To do this, inflate to one of the above numbers in this thread and drive the car up to operating temperature (engine and tires). On a flat surface, measure your pressures again and adjust until the tires are 40 PSI HOT all around. Continue driving with these pressures and monitor cornering and tire wear (over time).

Park the car back home and let everything cool back down. ~Now~ go measure your pressures. You will find that the fronts are different than the rears. This is now your baseline COLD temperature pressures--you know that these cold temperature pressures will result in the correct HOT temperature pressures....the ones that really matter.

You will have to redo this exercise as seasons and conditions change, but you get the point.

I typically inflate/deflate my tires when they are HOT. I note the COLD temp pressures just for a ballpark number in the future.

Good luck.

AM993

Same here. Used to run 36r, 36f and lowered the front pressure a few month ago: big improvement (better turn-in)

Chris W. - '96 Targa

+1, both with SO-3s and P-Zero Rossos.



-Chris

lucroberts

OK, it seems that the 36psi is the bulpark for all of you. Jeff, I'll do the 40 psi HOT exercise !
Thanks

os993

Another excellent mix is 32psi front, 34psi rear - nice!

TargaTango

+1

On my Targa with 17" standard rims, for the street I ran 32/34 with 03s and Michelin Pilot Sport PS2s. This was based on the following advice which was for 18" wheels but worked fine for me:

07-14-2002, 03:53 AM #38
"As you can see, others have contributed quite a bit to this subject. With a RWD, I think a 2 psi differential front to rear is good while on an AWD another psi in the rear tires works a bit better. Try 32/34 in your Carrera tires and see how that works. I am running 32/35 on my AWD Carrera 4S with great result both street and track.
__________________
Viken Bedrossian"

henkinc

Help me out guys. The conventional wisdom is that decreasing front pressure will decrease stick in the front - as the sidewalls lose their "stiffness" - and thus decrease turn-in. Is this incorrect?

RallyJon

There's a difference between actual stick and perceived turn-in. Turn-in and understeer are also terms which are used in different ways by different people.

I would say that lowering front tire pressure from say, 36 to 34, would result in worse turn-in but better grip. But that's just me.