Just bought new tires, couldn't get the Faken Azenis in time(they are backordered)I've got a track event at Sebring on Friday. I picked up Pirelli 700z in a 205-50-15 and need to know from you guys running this size what pressure do you use? Appreciate fast feedback
Momo

 

Is this on a ITR?

 

[QUOTE]I run 39 cold on all track tires except the Hoosiers which I run at 42 cold -- you really have to dink around and see what works best for you.

The P700z is not a track tire.

 

last month when I ran at willow springs, I started w/ 32F & 33or 34R. After a couple of laps, they were at ~40 all the way around.

yoshi - who forgot to mention that this was on Azenis 205/50R15

 

With a race tire the ideal pressure is not the same as a street tire. The race tire is designed with a very stiff sidewall so pressure can be run lower as to not over inflate or "Balloon" the tire and reduce grip. ie: I run 37 psi frt and 35psi rear on my ITR with Hoosiers, On street tires you need the extra inflation to keep the sidewall from "rolling over" or flexing.

Start with a higher pressure, 40, 42, 44....and mark the edge of the tire with white shoe polish, take the car on the track........come in and inspect the shoe polish as a gauge. If your not even touching the shoe polish= to much air. If you are wearing the shoe polish away on the side wall= not enough air, and go from there. You can also make adjustments to allow the car to rotate more/less by changing air pressures. Any one that has ever autocrossed that is at the track should be able to help you out.

I have never like pirelli tires on the street, however we have a Porsche 996tt, with mods (520hp) that had several hard track days at Mid-Ohio on a set of pirelli p-zeros that just wouldn't wear or chunk. Really seem to last on the track.

Mattj





[Modified by Dropspeed, 3:35 PM 1/23/2002]

 

If I'm not sure about what pressure to use for a tire, I find it's best to start with the car manufacturer's recommended pressures - in the ITR, that's 35F, 33R - and then adjust as necessary if you encounter any handling problems or uneven tire wear.

BTW, with the stiff sidewalls found in modern high-performance tires, I find the shoe polish trick doesn't work all that well these days.

 

BTW, with the stiff sidewalls found in modern high-performance tires, I find the shoe polish trick doesn't work all that well these days.
[/QUOTE]

The p700z is an older tire and not nearly as stiff as a S-02, S-03..........I ran them, in the same size, 205/50-15 as an "street" autocross tire about 5 years ago and the shoe-polish trick works fine on them.

Mattj

 

while we are talking about tire pressures, can anyone recommend a good tire pressure guage? nothing comes up using the search. also i tried the shoe polish trick once at the track, but could not get the white spots to come off my tire after a couple days. what works to get that stuff off?

 

I ran the P700 1 session on Heartland Park brand new to break them in & know their limits (to use as my street tire). You'll probably gain 4-6 psi on the track. Autocrossing - you would want alot more pressure than is needed on the race track. Start about 35-37 & check your pressure after your first session. Adjust from there.

Note: You will slide all over the $#%@#$% place on p700's on the track. Expect at least 4 seconds slower than your stock RE010's.

jmho - since I've used them (I drive ~25,000 a year!) but enjoy every mile.

 

Try Napa & btw use chalk instead of poli will come off easier & does the same trick.

Note: Oh yea - my kid has a bunch in the garage - lol

 

Yes, one of these from the Tire Rack.

Or, you can go down to your local Radio Shack and see if they have this one or this one. The latter appears to be the same as the second one on the Tire Rack site, but at a lower price.



[Modified by nsxtcjr, 7:25 PM 1/23/2002]

 

I recommend the best. I use the Intercomp Deluxe Tire Pressure Gauge. It's accurate, rugged and never fails! (It is worth the price)

(www.bakerprecision.com/intcomp.htm)