Jim Fischer 
2003 BMW X5 SUV 3.0i AWD 4dr SUV (3.0L 6cyl 5M)
Fine tuning your X5 is an Art
 Ride quality with a 3.0 W/Sport. Bouncing of the ride is extremely annoying for the passengers and driver at factory settings. The tire air settings on the driver's side door do not represent the dynamics air pressure has on this vehichle at all. I have 255/55r/18" tires Michelin mxv M&S. Mileage was 13 mph to 18 at very best.  I looked on the sidewall of the tire and a pressure of 51 lbs. I put in 47 lbs of pressure on all 4 tires. Ride is incredibly smooth, over bumps smooth freeway. The extra pressure gives the SAV 20.8 mpg aggressive driving all day long. 26 MPG @ 60 MPH with cruise. Much faster, better cornering. The solution to bounce. Start at 51 go dn 37p