Tire pressure on 01 Carrera 4 cab....

What should I be running the the front and rear? The manual seems to quote a very high number IMHO, what are you guys running? I have the 18 inch sport design wheels with the Pirelli tires that came as OEM equipment.

With the lower profile tires and performance characteristics of these tires they should be higher. Use 36 psi fronts and 44 psi rears. Once you've seen one of these expensive tires ruined (or worse cause an accident) due to under-inflation you'll be convinced. They really do need to run that high.

Loren, i don't agree with you. I have checked the tire pressures on my 02 C2 shortly after I took delivery of the car, the factory tire pressures are at 31 all round. My car was delivered to me right after it gets to the port and done with all initial inspection. Then, I tried couple different tire pressure setup, my car perform the best with 32/34 (F/R) on the track. Over inflat or under-inflat a tire could ruin the tire as well! Stock recommended tire pressures are weird to most of Porsche racers. Also, the weight of the car is also a major part when figure out the proper tire pressure, for a 3000-3300 pounds 996NA, 32-36psi is more than enough. The profile (sidewall) of a tire has nothing to do with the tire pressure. Tire pressure should remains the same due to the weight distribution of the vehicle, not the profile of a tire. <img src="graemlins/burnout.gif" border="0" alt="[burnout]" />

I have been running 32/34 for years on track, off track, slow speeds and high speeds. Never had a problem or got my tires ruined. The factory recommended pressures don't make any sense and certainly don't help the cars handle well.

That is what I thought, I cant imagine going to the track and increasing tire pressure from 44 in the rear like people say, then running at over 50 hot tire pressure. Why do people tell everyone to increase tire pressure at the track? Should it not be the other way around with our low profile tire that do not roll over on the sidewall very easily?

I don't know who suggests raising tire pressure for the track... but where I track my car most folks lower tire pressures. You are right tires heat up and the pressure will go up so you lower tire pressure (unless of course they were too low to start with). Everyone has a right to their own opinion so I won't argue. What pressure you run is your business. I have seen low profile 40 and less series tires that have the sidewall torn apart from under inflation and basically destroying the tire sidewall in hard cornering. So run the pressure you want... but ask yourself why Porsche wants such high pressures... perhaps for your safety?

Silver, I agree with Loren. Track racing should translate into lowered pressures not higher. I run 38/44 on the street, but would lower it at least 6 psi on the front/back for track (not that I am a track expert -- just what I have read in the extensive archives on this topic). Viken's recommended track pressures seem the right amount as well. But just remember directionally, track pressures (cold) are always lower than street/normal driving. Regards.

[quote]Originally posted by Loren: <strong>I have seen low profile 40 and less series tires that have the sidewall torn apart from under inflation and basically destroying the tire sidewall in hard cornering.</strong><hr></blockquote> Do you know for a fact that low pressure was the reason for this destruction?

A question for those of you that have run higher pressures for longer periods of time, say, 5000 miles or more. Have you looked closely at the tread wear across the width of the tread? This can be some indication as to whether the pressure is correct. With over-pressure, the center may wear slightly more than the edges. Of course, this wear measurement isn't something to solely determine tire pressure because there are so many other factors involved. But if you are noticing more wear near the center you may consider the pressure a bit too high. The converse is also true. Cheers, Ken

Ken, I have to agree with you. If, you have too much pressure on your tires and 36/44 is too much. You wont get good contact with the road. Therefore the car wont handle as well with lower pressure. I recently when to a porsche dealer and had my tires rebalanced and the guy put in 32/36. I ask the service guy and he told me that with the 36/44 the tires wont wear correctly. Anyways, I think best to test out whatever fits you better.

Ken, 44 psi on the rear tires will wear the center of the tread in no time. Absolutely, the most absurd pressure recommendation I have ever heard of.

[quote]Do you know for a fact that low pressure was the reason for this destruction?<hr></blockquote> Viken, I was shown two different tires by the guys at Custom Alignment (also a TireRack installer) when I had my 4 wheel performance alignment done. They raised the presssure in my tires and took me over to see the tires they had removed from another 996 the week before. They said the guy was running pressures in the low 30's and simply overheated the sidewall in hard cornering. You could actually see the side cord on the inside of the tire while the outside looked normal one tire and the other had a "wrinkle" in the sidewall from the distortion. The tires were S0-2's with over 50% of the tread left. The techs were pretty serious about not running under 36psi in the fronts and at least 40 in the rear.

Loren, There are way too many people, including myself, running pressures in the low 30's at very high speeds on and off track. We have been doing so for several years and I don't personally know anyone with such damages. As such, I am going to assume that the tires you saw were either damaged due to another reason or the drivers ran much lower pressures that we are discussing here. As I said in another thread, if you don't think you will feel a difference or you are too skeptical to deviate from Porsche's recommended pressures, then you should stick with them.

Loren I am running 32/34 F/R tire pressure on my '02 C2 for 8 months (7000 miles). I notice the center of the rear tires worn out very quick (a sign of over inflation of the tire) while the shoulders of the rear tires wear out very normal. So, running the PAG recommended tire pressures could only make the tire wear on my rear tires worse, not better! Besides, I have experience with 35/38 F/R tire pressures on my car, the car obviously has less grip/traction and handles worse & center of the rear tires worn out even faster! I have P-Zero Rosso 225/285 on my car by the way.

I think the variables are endless, but one thing works for me and others, is observing the small triangles located on the side of the tread after a session on the track. wear marks should be visible just to the point of the triangle. wear more or less from the point indicates wrong tire pressure. Roy S

You are all driving me nuts I was perfectly happy running at the reccomended pressures. Now you've all got me checking for tire wear every morning. Everytime I take a corner hard, I expect the tires to shred or blow up any moment. Oh, well. One more item to get compulsive about. <img src="graemlins/drink.gif" border="0" alt="[cherrsagai]" />

palting <img src="graemlins/nono.gif" border="0" alt="[nono]" /> loosen up man! i don't think you can go wrong following factory rec's. i have almost 7k mi now on p0 assyms. i see no sign of excessive wear in center yet and 1/2 tread is still present in back--slightly more in front i have followed 36/44 rec from the beginning. i am satisfied both with grip and ride quality-maybe because of 996 c4s instead of 993 or c2? i will confess that i went down on hands and knees with a flashlite in my garage yesterday to check rear tires! <img src="graemlins/c.gif" border="0" alt="[ouch]" /> i guess i was worried, too! <img src="graemlins/roflmao.gif" border="0" alt="[hiha]" /> how are your tires wearing? ride and grip good? i love my c4s <img src="graemlins/jumper.gif" border="0" alt="[jumper]" /> <img src="graemlins/bigok.gif" border="0" alt="[thumbsup]" />

Tires seem to be wearing out fine at 5100 miles using the factory pressures. Grip is phenomenal. Took best time for a local AutoX for class/level . I actually enjoy having a reason to get on my hands and knees to check out the car!! <img src="graemlins/c.gif" border="0" alt="[ouch]" />

palting- hands and knees? enjoy? you're a sick man! get out and drive it instead! gas is cheap in america and this car is the most fun i've had on wheels since my 79 911sc! i can't get over urbanski's bad luck compared to ours. i hope he takes a firm stand. he deserves better!