Hey I'm currently running 235/40/18 Pirelli P7000's, does anyone know whats the best psi I should inflate these to for overall performance?

 

32 psi

 

I say, play around with the pressures. But first! Get yourself a quality pressure gauge.

http://www.tirerack.com/accessories/airgauges/air5.jsp

 

http://son.pca.org/Technical_Article..._pressures.htm

 

according to the optimal formula: you that the rear require a tire to hold 53 psi ... I don't think there is a tire rated above 50 psi over than truck tires, class d rated ... nice math though !!

 

I currently have 37 front 31 rear on 235/40/18 18x7.5
I used to run 33 front but it seems too low and squishy around turns so I now have it 37 for both my old tires and my current ones for over 2 years now. rears I always keep around 30-33

 

Run what Nissan says to run, as long as the tire load rating is more or less what is stock.

However, one good way to guage correct pressure is to find a pressure where the tire wears evenly between the center vs. the edges of the tire. I have gone through a set of Bridgestone RE92 and Bridgesone Blizzak WS50s. I ran both at 32 psi. Both had excessive wear in the center, at least 2-3 /32.

Regularly measuring the tire depth will let you know if you are on track. A tire depth guage is a 5$ stocking stuffer that you will love. (only 246 days until XMAS)

 

I had better grip at 35/33psi with very little sidewall roll over, but currently I run 37/35 for pothole resistance on my 18s. And make sure your tire guage is accurate.