jran76

I have some Sumimotto 235/40/18 Z rated tires, and am not sure what to inflate to. They say 51 PSI max on the side, my spare (a Khumo Escta 712 Z rated, same size) says 44 PSI max.

Any ideas (normal and track)?

bill99gxe

iTrader: (1)

Michelin's website has a convoluted method for obtaining a tire recommendation for Maximas with "Plus 1" 235/40 18s. They recommend 33 PSI front and back in that particular size.

As for track, I am clueless.

jran76

Good enough, thanks.....

xHypex

iTrader: (1)

Just for some real life data for you I run about 34 in mine You don't want to overinflate them, but the more pressure you run the more it evens out your ride. I usually err slightly on the high side in case I lose some pressure over time.
-hype

Uromax95

For normal driving I have found that 28 psi (front) and 26 psi (back) gives the best combination of softness without underinflation. I have Goodyear Ducaro F1 235-40-17Z which is about the same as yours in 17". I have tried from 26psi to 32psi in front and have settled at 27-28. For the track I would not know for sure but It would probably be higher to avoid understeer.