996FLT6

Now that this controversy will go on and on can someone tell me what the correct tire pressure I should use for thr darn spare tire for the road and supposedly designed for the crush zone design? I think majority of owners with performance oriented cars will experiment with tire pressures no matter what car/tire manufacturer recommends but I do think PAG's recommendation is all about liability concerns versus performance. It is a business afterall and I too would be concerned if there is any liability issues. PAG probably researched that 36/44 will keep it safe for majority of owners and if one decides to lower their tire pressures and get into an accident then it's the owner's fault not PAG's. That's business. Regards. Mike

Viken

The misinformation I am referring to is the one that came from your genius mechanic. I cannot be certain whether he got it directly from Weissach or not but it is gross misinformation nonetheless. It also saddens me to see so many average people who believe the misinformation and spread it in such an infectious manner. I would have believed that most people have the common sense to know the difference.

KC993

Trying not to step on anybody's toes here...
In the Owner's Manual which I would think is as official as it comes from Porsche, stated on page 5 and 155 that 36psi F&R for 17" and 36psi front, 44psi rear for 18" for proper COLD tire pressures on "Porsche appoved tires" only.

DJ

Er... what's your point?

KC993

Just trying to point out that everybody knows where Porsche stands on this issue and what tire pressures to run are in our own hands and believes.

JimBob Jumpback

Hay Bubba,

maybee dis be helpin uall. it werked fer ol Red.
hep be onda way fer u

affer u be doin dis klas, den u kin lookee at dis tred agin.

KC993

Thanks for the pointer, I knew I was missing somthing when I was growing up.

Viken

Where have you been all this time?

DJ

Agreed. If what you mean is that it is pointless for us all to wait with baited breath for RS993 (Phil) to return from the mountain with words of wisdom from his secret contacts at Porsche, then yes, I agree.

993RS

Come on guys. I do not have any "secret" contacts, I am going through official channels, phoning Porsche in Stuttgart and Weissach. The only advantage I have is that I speak fluent German, which is helpful. I was told to phone back early next week. I see already though, that no matter what they tell me, this board will not believe it. The board obviously does not consider Porsche AG as a competent and reliable source.

I am sure that safety considerations are a prime factor in Porsche AG's recommendations.
Even if certain performance characteristics improve with lower tire pressure, how can you be sure that a safety risk does not insue? Do you guys have labs to do the testing?

http://www.cbsnews.com/stories/2001/...in308749.shtml

SundayDriver

Yes, Phil, we do have testing labs! We have race tracks, running many cars for many, many miles. Pyrometers, pressure gauges and the experience of skilled drivers evaluating the handling of their cars. Additionally, I spent quite a few years as an automotive tesing & development engineer - some of that in the tire testing area. For about a year, I worked with Porsche engineering (I was their customer on a development project).

Posting that story about underinflated tires shows you really have no clue what you are talking about here. The problem that article addresses is running tires so underinflated that a) They build excessive heat due to squirm and b) not enough pressure to support the weight of the tire under moderate/hard cornering. The suggestions being made here are track proven - exactly the venue where temperatures get the highest (where squirm would be fatal) and where handling is pushed to the limits.

This is not about whether Porsche engineering is competent. It is about you spewing BS from mechanics, etc - ignoring the fact that factory recommended pressures are a compromise of many factors. It is about you back-pedaling and changing the topic from the wrong information you continue to try to spread here to something else.

Phil, I know your intentions are good, but the fact is that about half of all the technical information you post is just dead wrong. There are plenty of other boards where this is the norm, but this board has been built over a period of years and provides good solid technical information. We have a long history as a community that will not allow technical BS to go unchallenged and that is why you are contantly challenged here.

993RS

Mark,
I do not know how you came to the conclusion that I do not know that the recommended tire pressure is a compromise on a number of factors. I was also under the impression that this is a discussion board. I am therefore confused at your aggressive tone. If this is a board in which only a small number of old hard-core posters should answer questions, I suggest that the rules be changed accordingly.
As to the Firestone story, I just noticed that the tire pressures sometimes recommended here are really way below what Porsche AG recommends. 34/36

SundayDriver

Looking back, you did say that you know it is a compromise. You also made statements about how the pressure was really for high speed (European) drivers, then said it was really for the average driver, then said we might want lower pressures for US driving. You are right - I can not possibly reach any conclusions about what you know - I apologize.

You earlier said:
These are both very agressive comments, though worded in a passive-agressive manner. You should expect agressive responses when you set an agressive tone.

This is a board where all are welcome to provide ACCURATE answers. Look at the large number of new users who are constantly welcomed here, based on their thoughtful contributions. I am not one of the original group, nor are many others who you likely consider to be "old hard-core" posters. We came in by trying to understand the community and added value where we could. We did not come in by spamming the board with photos and off topic posts and a bunch of incorrect information. You will get called out when you post information that is not correct or suspect - I expect, and get, the same when I am wrong.

If you want to continue debating this topic, I will be happy to do so on the OT forum. We are getting too far away from the intent of this board, IMO.

Viken

Phil,

I think you are missing a few points here. Let me see if I can clarify them for you. Sorry, I can't do it in German. Hopefully, my broken English is adequate for your understanding.

1- You started this thread by posting misinformation. Granted, that information was given to you by your genius mechanic who you have come to trust after years of experience and you probably had no way of telling if it is accurate or not.

2- Some of us attempted to correct that information. I tried to use common sense while others were basing their comments on pure driving experience. The reason why we did this is because there are many people on this board who happen to drive their Porsche's on the track and are interested in accurate information.

3- No, Porsche's tire pressure recommendations are NOT a compromise. They are ridiculous at best because they don't help the car and/or the driver do anything right. Perhaps, Porsche thinks these pressures are best for high-speed Autobahn driving. If so, they should start calling their cars grand tourers rather than sports cars. I say this, because 36/44 makes any Porsche handle like crap on a racetrack. This fact cannot be argued by anybody including a Weissach engineer. I dare you to go out and try it yourself if you want to see what a non-average Porsche driver can experience.

Finally, my suggestion to you is to go back and slowly read this thread from the top over a glass of your favorite libation. That ought to help you realize how deep a hole you dug for yourself to sink in. Of course, Dan tried to give you that warning but, as you sometimes do, you ignored it.

Anir

I might add that 36/44 also makes a 993 handle like crap on a driveway, neighborhood streets, freeways, and I'd imagine the autobahn as well. It's a poor choice for any type of driving - low or high speed, straight-line or curves.

Phil, I think the point Viken, Dan, Mark, and others have been trying to make is that many of us have indeed driven our cars at sustained high speeds such as those seen on the Autobahn. Our collective experience is not limited to speeds of 65 mph and less as you suggested in one of your posts.