just got a set of Direzza Z1 to replace my 615 on my 18" WORK. i heard the side walls of the Z1 are a bit softer than the 615. if so what psi should i run for the streets and tracks? i have WORK 18x8F - 18x9R and 235/40F - 265/35R. THANKS in ADVANCE

 

I ran 35 psi all around at a track event late month it was 92 degrees and they felt great . Higher pressures the tires were a little loose I would say 35 psi hot is good fro street and track.

 

THANKS