We ran it the other week, and I am stumped on these new D06 slicks. I am thinking they like the higher air pressure of 12.0psi but it was inconsistent. 9psi seemed too low and unstable. What pressure should I be using?

Are they a radial slick ? Ron

Slicks.....

12.5 to 15.0 psi

You have to tailor the air pressure to each application. Tire design, static weight, transfer, suspension, shocks, "hit", etc. all play a part. If you're not getting a full-width footprint at higher pressures and it's unstable at lower pressures, it may help to go to a wider rim.

I have Hoosier's 9" lightweight radial slicks on 10" rims and found that 20 - 21 lbs works best, despite a little extra wear in the center. But it's contacting all the way across the tread. When the rubber off the tread was fraying over the edge towards the sidewall too much, I added air. Some Stock class guys run down to 14! (I swap the slicks from side to side after every race to help even up the wear. I've never had equal side-to-side wear if I didn't.)

A wider rim will allow more air pressure, which stabilizes the sidewall and prolongs its life in addition to helping the car on the top end.

The car in my sig wouldn't hook under 12 psi, best at 13-14

Well 13.0psi was not working 12.5 didn't work, 12.25psi and it hooked and I broke out. Seems to like 12.0-12.25 best. Been as low as 11.0 and it was unstable.