silvercar

What is the proper cold tire pressure just for street driving for SO-2s on a 95 993 with 285x30x18 on 10" wheels rear and 225x40x18 on 8" wheels on the front. Is this what Bridgestone reccommends for 993 with thises tires? I want to minimize tire wear but not sacrifice handling and/or ride comfort.

Thanks for your help
Paul

Anir

Paul,

I'm not sure what Bridgestone recommends, but I run 34-36 front / 36-38 rear for the street. I don't worry about tire wear, because I tend to replace tires well before the actual tread is gone as the handling characteristics degrade. I changed my last set of S-02's all around after 8,000 miles (including six track days), even though 50% of the tread still remained.

Kim,

I've consistently achieved 40 all around hot (my target pressure) when starting with 32 front / 34 rear at DE events, but our climate is likely a bit cooler than Cali's.

JimBob Jumpback

[quote]Originally posted by silvercar:
<strong>What is the proper cold tire pressure just for street driving for SO-2s on a 95 993 with 285x30x18 on 10" wheels rear and 225x40x18 on 8" wheels on the front. Is this what Bridgestone reccommends for 993 with thises tires? I want to minimize tire wear but not sacrifice handling and/or ride comfort.

Thanks for your help
Paul</strong><hr></blockquote>

Well Bubba,

Wit doz tyreds, u gotz abot 700 sqarley inches o tired tmes for tireds equals pert neer 2500 squared inchas. sum bubbas says ta run 32/34 cold but JimBob nos betta. u cee ifn u run 12/14 u save 20 pounz for sqarely insh timez 2500 inces of 50,000 pounz an dat iz awl unsprining wait. ur kar iz gonna fly likey a buzzurd wat dun eated hot peperrs. Sow takez mine advice an run 12/14 ta gos reely fastester.

Yur Fren,
JimBob

Jim Michaels

Hey, JimBob:

Good to here from you again. I see you remembered what I told you when I was helping you carry your air tank that you just filled up with 125psi. Whew! It sure was heavy. Now don't forget that other thing I told you. Switch out that old air for fresh ever 6 or so heat cycles.

Your buddy,

Jim

JimBob Jumpback

[quote]Originally posted by Jim Michaels:
<strong>Hey, JimBob:

Good to here from you again. I see you remembered what I told you when I was helping you carry your air tank that you just filled up with 125psi. Whew! It sure was heavy. Now don't forget that other thing I told you. Switch out that old air for fresh ever 6 or so heat cycles.

Your buddy,

Jim</strong><hr></blockquote>


Yo Bubba Jim,

I member awl uawals help anna I preciate its. I iz gonna tellin u mine nu secretes fer tyrs. I iz uzin hydergin in mine tyreds. its is mucho litar anna u kin uze it jes likey nos an lite it up anna go eben fasteder.

c u at da trak,
JimBob

Martin S.

I am too lazy to go out to the car and get the owners manual...but I believe it us (cold) 36 psi front, 44 psi rear. Most don't run them this firm, for 18" wheels.

See the following post today from Phil:
__________________________________________
993RS
Guru

Rennlist Member

User # 4408


posted 07-11-2002 02:34
--------------------------------------------------------------------------------
This comes up time and again. My Porsche mechanic told me that it is actually not Porsche that makes the cold tire pressure recommendations, but it is the tire manufacturers themselves.
The cold tire pressure (36/44) recommended in the Porsche manual is above all addressed to European drivers who can hit very high speeds in autobahns. It is dangerous to drive at high speeds if the tire is not stiff enough. Hakinen, two years ago, had an accident on a straightaway at high speed, and was then criticized by Bridgestone for running on too low a tire pressure.
If you are competing in a track event, you will, of course, have to run a much lower tire pressure, because the tires will heat up much more. But this is not the case for street driving.
The majority of the drivers on this board being from the U.S. will never drive their cars above 100 mph probably (and even that rarely). So probably a lower tire pressure might be considered for street driving for more comfort. I run with the recommended tire pressure not only because I hit the German autobahns now and then, but, because I personally find the tires firmer and preciser then with lower pressure.

--------------------

Phil
Join Rennlist!
My Homepage:
<a href="http://mypage.bluewindow.ch/a-z/YellowandBlack/" target="_blank">http://mypage.bluewindow.ch/a-z/YellowandBlack/</a>

Viken

[quote]Originally posted by Martin:
<strong>See the following post today from Phil:</strong><hr></blockquote>

And, see the following response to Phil:

<a href="http://forums.rennlist.com/forums/ultimatebb.php?ubb=get_topic&f=3&t=004246" target="_blank">Topic: Tire pressure: Neverending story... </a>

JimBob Jumpback

Bubbas,

I wood be takin da advise o 993Rss fer a buncho reezons:

1) 993rs be a guru and viking onlee be da modernating.
b) 993ress be libin inna swisslant anna dey knowz awl bout kars choklatz an swatchas. vikings knowz alot aboot boatz an dem hatz wat gotz hoarns. Hey viking bubba, kin u sent me onna dem horney hatz cuz i tink dey iz kool.
4 - it bein obveeus to da keenlee traned brane o JimBob dat 993rs nos lotsa much moar bout eberyting dan viking.
f: 993ars dun goed ona fakteree tour o dem porch kars wear he teched da porch kar inganears howta due a bettr job ona dere kars.

yuall lisen ta 993ars cuz heuns iz pert neeer smarts az ol JimmyBob.

Yur fren,
JimBob

SundayDriver

[quote]Originally posted by Viken:
<strong>

And, see the following response to Phil:

<a href="http://forums.rennlist.com/forums/ultimatebb.php?ubb=get_topic&f=3&t=004246" target="_blank">Topic: Tire pressure: Neverending story... </a></strong><hr></blockquote>

Viken is correct. While there are many good mechancis, few have ever worked in the engineering department of a vehicle manufacturer or tire company. Recommended tire pressure is set by the manufacturer with the help of the tire company. The pressures are a compromise between ride, handling, noise and other factors. They are also set high to provide a safety margin - If you ignore your pressures they tend to get too low, not too high. It is dangerous to run on underinflated tires (that does not mean under the recommended, but under the lowest safe pressure) so it is safer to get most drivers to overinflate, rather than underinflate.

Chris C.

Silvercar:

This has been discussed many many times...a check of the archives will give you more opinions than you can shake a tire iron at.

I ran 34/36 for 2 years, street and track (hot!), with good results. 44 in the rear will cause your the rear to get darty at normal US highway speeds. YMMV! Play with pressures yourself to find a range that is comfortable for performance and keeps your wheels from bending in normal pothole-dodging maneuvers.

PramTT

The following are quoted from the Porsche TSB (from Alldata) on tire pressure:

Inflation Pressures

16 Inch Wheels 17 Inch Wheels 18 Inch Wheels

Front: 2.5 bar (36 PSI) 2.5 bar (36 PSI) 2.5 bar (36 PSI)
Rear: 3.0 bar (44 PSI) 2.5 bar (36 PSI) 3.0 bar (44 PSI)

The above tire pressures are valid only for tires approved by Porsche. Tire pressures must be checked and adjusted cold (approximately 20 degrees Celsius or 68 degrees Fahrenheit). Tire pressures can never be lower than what is specified above.

Do not drive on under-inflated tires under any circumstance!

Chris C.

Kim:

Sorry...I should have been more explicit. I run 34/36 HOT on the track. You must drop them down after each run to avoid severe overinflation. Hey--have any pics of those painted seat backs??

PRAM: we can all read the manual, but we are discussing real world experiences from several people with many years of driving experience. Run what you like in your car...my 98 (and my prior 97) 993 cannot be driven in as straight line at 55 mph with 44psi in the rear.

BTW, I am now running (and loving!) Pilot Sport Cups on the street and track. These too will skate to the point of uncomfortable highway driving when the rears are at more than 38psi hot.

993RS

See my response to Viken.

Don Magee

Try this: Inflate to factory specs, go drive your favorite twisty road as hard as you safely can. Savor the experience until your tires cool back down to cold pressure. Lower to 32/34 or 34/36(your call) and drive again--very hard. If you notice little or no difference, you are not driving it the way it should be driven-- sell the car to me, cheap. If you prefer the factory specs, great; however, I'll be shocked. You should find traction, handling and ride much improved at the lower settings. In case anyone cares, I prefer 32/34 to 34/36 because the rears at 36 cold go to 44 hot and get loose. Loose when hot is good for a girl, but not optimal for a tire.