PSI for 20" wheels (275/315)?
 

(2005 4.4 X5) I'm running 20" wheels with 275 in the front and 315 in the rear. I've done some searching, but not sure what the right PSI would be.

I had 315's on the rear of a Camaro before and too much or too little air would wear the tires funny (solid axle rear, so no alignment issue).

I don't recall what factory inflation is (32 or 34 sounds familiar) but I run mine at 36psi as a matter of preference. No unusual tire wear except for the typical BMW negative camber wear which can be combatted by regular rotations.

You are aware there's a tire inflation guide on the driver door jamb, right?

I recall from memory that on the 4.6 on 20's it's 32/32 for a standard load.

More air for a fully loaded car, cant remember how much at the moment.

Ditto...its on the driver's door or door jamb...plus it's also in the owners manual. :)

The "recommended" inflation is dependent upon speed and number of passengers/cargo. If the recommendation doesn't suit your needs...then adjust accordingly in small increments: