Toby Pennycuff

I used to have the Pirelli spec sheets and information on these tires - optimal pressure and temperature readings, and damned if I can find them. Checked the JX2 site - Nada. Checked the Pirelli sites and could find only general information.

Anyone have Pirelli's specs on these tires and would you be willing to share? Thanks much!

Toby

Toby Pennycuff

Frisby Racing Tires' (IMSA tire supplier?) site suggests starting cold pressures at 24psi front and 26psi rear. Hot pressures are always supposed to be ABOVE 30psi front and32psi rear. Max hot temps are 230F with a 50F spread.

These starting pressures seem high. Thoughts?

kgorman

https://jx2pg.com/technical/

Toby Pennycuff

Thank you, sir. Could not find this info to save my life! Appreciate the pointer to this info.

Toby

kgorman

I bookmarked it after screwing up pressures my first time out

BBMGT3

pirelli DH we used to get pressure targets from pirelli at each weekend

bit higher than michelin.. 1.9-2bar usually

Viperbob1

Cold starting pressure = reduction in liability for tire company. at 24/26 you will make 2 laps and be in the pits to drop pressure. couple more, and in the pits. Start a race like that and 1/2 way through a Sprint you will be in the mid to upper 30s and ZERO grip.

Frank 993 C4S

Correct!

Toby Pennycuff

Exactly why I asked. Thanks for the info and keep it coming! BTW, certainly not trying to make off with anyone's hard-earned data here. Just looking for information to use as a starting point - again!

Toby

bgiere

What cold pressure do you typically start with Bob ? First time i used Pirelli's last summer at the IGT race I had the experience you described ! I started at 22/23....At the halfway point tires were way to slippery !

FLA997

That's actually hilarious...Bob nailed it.

Viperbob1

Depends on track, heat, sun, etc. Generally 20-22 lbs is a good start. Will allow for not too low pressure to be a still safe, give you a good practice session, then set when you come in. Should be close. depending on driver, car, track, heat, etc (and nitrogen vs straight air) you can see hot vs cold temps 10-16 psi on the rise over the course of the first session

Slakker

Strange. 22 and 24 lands me within a psi of 29 and 30 every time. 2700lbs 996 with driver.

Viperbob1

Caveat of driver, track etc. 6-7 lbs is stupid low for an increase...

bgiere

22/23 had me up to 35ish hot pressures after 3-4 laps at Mid-O in September. I evacuated the air and refilled with Nitrogen for the rest of the weekend to try and keep things easier to maintain.