Getting ready for my first DE day and was wondering what you folks are using for cold initial tire pressures for the 20 inch PZeros?

SMATL mentioned that he starts around 34/39 (F/R). What do you guys use?

On a side note, I got approval for the permanent number 991. Pretty Cool!

 

The OM calls for 36/44 (F/R) for full load which is usually what is considered best for DE track events.

 

THanks. I've been out a few times and found that 32/35 cold is much better for me.

 

30/33 cold for me was great.

 

One yer later and with more trials, this is also the case for me (but i mostly run R888 on the track).
The cold temperature is a bit tricky in fact. My goal is to be around 40/40 hot. I drop the pressure by ~4psi front and rear (I never have the rear up to 44) when I get at the track and bleed the tires to be at 40/40 right after the first session when the tires are hot. I keep monitoring during the day

 

I did my first track day in my own car two weeks ago and I perused the forum extensively for info on tire pressure before that. For daily driving I've been running 32/35 and noticed as the tires warmed up the pressure would increase by about four PSI. On track day I started with 36/44. By the second thirty minute session my rear pressure was at 52. So I was in a constant battle to let just enough air out but not too much. The air temp started in the mid 50 s and ended in the mid 60 s. For my next track day I think I'll start at 34/40.

I did notice the on board TPM system is pretty accurate, but I do think it is wise to have a high quality pressure gauge. Some of the more experienced drivers had air cylinders so the didn't have to be as careful about letting air out as I had to be.

Have fun!

 

That's way, way too high. Porsche recommends starting at 31/34 for normal driving, and since on the track you tend to get the wheels much hotter, it makes more sense to go lower I found if they get about 40 when hot, they get very slippery.

 

Optimal Tire pressures will vary quite a bit between different tires. On the stock pzero I found that I had the best grip and most consistent feel at hot temps of 28psi front and ~31psi rear. I've only done a few days of testing with the car, so I may still make adjustments.

I originally started at hot temps closer 40psi. The car didn't feel terrible, but I was getting more under steer on corner entry and over steer on exit then I was expecting. I started lowering the pressures and was amazed at what a big difference it made. It was like a different car.

At 28/32 hot I am also not getting excessive sidewall rolling over. In general the tires seem to be wearing very evenly and better than I expected. My car has SPASM, no PDCC and -1.8 camber front and -2.2 rear. It is completely stock.

 

I did my first DE in my new 991S two weeks ago. The car is completely stock with PZeros and the full alphabet soup: PDK, PDCC, SPASM, PTV, PSM and (just joking here) LSMFT! (How many here remember what that stands for?)

Checking tire pressures immediately upon pitting after every session, my goal was to keep the tires at around 37/39 HOT. Temperatures were in the high 70's, so when they cooled off they were way down around 30/32 or thereabouts.

I concur with others' comments - at about 40 psi they start to get slippery. If they ever get over 40 psi I'm letting air out at the first opportunity.

Keep in mind that Porsche's "recommended" settings are for the street, and have to account for things like potholes. They also dial in understeer to keep us from driving off the road backwards, like the old 930s loved to do. In a controlled environment like a track, those recommendations are not so relevant.

Of course, bringing your tire pressures down that much means that you're going to have to air up the tires for the drive home, unless you're really careful about potholes or have much better roads than we have here in Southern California. I always bring an air compressor to the track so I can air up before the drive home.

Note that Attila's recommendations above refer to using the car in an AX event, not a DE. I think I'd run higher pressures than that at the higher DE speeds. But he was running pressures significantly lower than me at that last AX and he cleaned my clock - so I'm going to go lower next time! (I will readily concede, however, that there was more to that time difference than tire pressures. He's a really good AX'er!)

DMoore
'13 C2S
'10 Panamera 4S
PCA National DE Instructor / POC PDS Instructor / PCA AX Instructor

 

I should've searched for this thread before I hit Willow Springs today. I was running 36/44 while the temp was around 60 degrees. During my second session the temp went up to 75 and my tires were at 42/50. I ended up sliding around at almost every turn. I'd suggest staying below 40 psi or you could end up in the dirt. Besides the tire pressure, the track day was a blast!

 

Turn 2 eats tires for lunch.
How was your tire wear?
Did you run your street tires or a 2nd set?

 

I just ran my street tires. They looked melted at the days end, but there's still a decent amount of tread left.

 

Bumping this very useful thread to see if people have refined their tire pressure targets?

I will be doing my first DE at VIR this week end (on my stock P-Zeros). Stoked.

 

As others have mentioned, pressure will somewhat depend on the tire, the track, and your driving style.

General rule of thumb, and a good starting point will always be 38-40psi hot, especially for a street tire. R Compound tires like it a tad lower.

I find the stock tires pretty good actually out on track and aim to be around 38 front and 40 rear, I have a C4S and find I get a touch less understeer mid corner with those numbers.

But you do need to play around a bit to find what works best for you.

 

Understood. Just helpful to have a starting point from those of you with experience. Thank you.