2.5 BAR == 36 psi

 

Heinrich,

I can deal with hyperbole, but I've been wrestlin' with my thoughts here (admittedly, like a sumo), and I just don't understand where you're coming from. According to your earlier post, 36psi would be in The Danger Zone, and anyway, this is for the GTS' 17"ers, which only underscores Swift's position.

So, what I'm saying here is this: I don't know how you can be so distrustful of the Porsche spec inflation pressures to the extent that you claim adhering to them is crazy and unsafe. Not only do I have no previous experience with Porsche that would reinforce that position, I can't imagine what kind of rationale would be at work at Porsche to deliberately specify "unsafe" inflation pressures. What gain did they make in doing so?

Don't get me wrong, I respect you, Heinrich, and I respect the questions you're asking about the factory specs. I also understand that inflation pressures are always compromises between traction and economy (of wear and fuel), but I'm having a really hard time getting my mind around this.

Personally, I ran the 16"ers at spec, and the 17"ers at 36psi/40psi. I will certainly try the lower inflation pressures (i.e. 36psi) on the rears next season, although with my 2.20 rear end, loss of traction at lower speeds, under acceleration, is not an issue for me ( ). I can easily get myself into "yeah-you're-definitely-goin'-to-jail" situations on the higher inflation #s without problem, but still, curiosity begs!

 

But the front is always higher than the rear. And neither of them go above 40 psi.

 

Chaad, 36 is not in a danger zone Dude. 44 is.

I don't think 36 is the right pressure for street, yet 36 is still perfectly sane. If you really want to run high psi, perhaps 38f/36r, but no more than that on cold tyres on the street in my opinion. And on the low-end, I'd go as low as 30 but no lower. I like less pressure because erring on that side gives better straction as long as you're within the good zone, which in my opinion is FRONT 30 - 38; REAR 30 - 36.

 

Chaad, Porsche didn't specify these pressures deliberately, it became very clear to me what was going on when I saw that my 911 had very similar pressures listed, I think it was 29 front 38 rear. I have to tell ya ... I'm leanin' in the direction of maybe a little typo on the 44 and that it was actually intended to be FRONT 36; REAR THIRTY-four

 

One more thought Chaad .... I did indeed have MASSIVE problems with one car I bought. I could not figure out what the heck was wrong when it kept repeatably losing the tail time after time ..... unlike any other 928 I had owned. I was shocked.

Till I checked tyre pressures (bought it from a friend and avid 928 clubster). Wanna guess hte rear pressure?

45

 

Yeah, this is the part I'm having a particularly hard time with. "Porsche didn't specify these pressures deliberately"?? It's like "heinrich vs. Porsche," so you see why I'm grillin' ya 'bout this, don't ya?

I love you, man, but I don't want to lose my **** at 150mph (or anywhere, for that matter) behind some bull**** like "Some dude on the internet said..." Right?

 

The point of my post quoting the GTS specs somewhat supports Heinrichs position. The GTS is a heavier and faster car yet Porsche changed the tyre pressure spec. ..........why? Were they wrong all along?

IMHO the rubber today is far far superior to what it was, we do not run at autobahn speeds in North America (well most of the time) and safety is a huge factor; I drive hard and inflate all 4 to 33psi.........never lost either end.

 

There she is!!! Post # 928!!!














<------------------------------ ( )

 

well that changes the topic somewhat..............here's to 928 more Chaad

 

vs


So Chaad .... .... your words. In the first post you say you cannot imagine Porsche specifying unsafe pressures deliberately. We know that thee ARE UNSAFE by the specs from the manufacturer of the tyres. So either Porsche specified UNSAFE pressures deliberately or they specified UNSAFE pressures accidentally.

Which do you think it is?

 

Heinrich,
I didn't see where those pressures are listed as "unsafe by the manufacturer." Which manufacturer would that be?

 

Dude, see my quotes from Good Year. The point is this. Ask mark Anderson; Mark Kibort; Bill ball; Rich Sanders above; anyone who knows a squish about any car and tyre pressures ... and what you will hear is this:

45psi cold rear pressure will not get you traction, and exceeds the MAX pressure of many tyres right from the manufacturer.

Is that dangerous?

 

I'm really sorry I was drawn into this friggin thread but I'm here now, and I'll stay till I've answered all your questions. 44psi rear is not correct. period.

 

Dude, your earlier post refered to a) never exceeding the max psi stamped on the tire sidewall, and b) max pressure (for Goodyear) when seating the bead of a tire, which is different than operating pressure.

Am I missing something?